Home About us Contact
|
Home About us Contact | ||
|
|
||
Genetic Differences (genetic + difference)
Kinds of Genetic Differences Selected AbstractsDensity-dependent polyphenism and geographic variation in size among two populations of lubber grasshoppers (Romalea microptera)ECOLOGICAL ENTOMOLOGY, Issue 5 2009JASON E. JANNOT Abstract. 1. Density-dependent phase polyphenism occurs when changes in density during the juvenile stages result in a developmental shift from one phenotype to another. Density-dependent phase polyphenism is common among locusts (Orthoptera: Acrididae). 2. Previously, we demonstrated a longitudinal geographic cline in adult body size (western populations = small adults; eastern populations = large adults) in the eastern lubber grasshopper (Romalea microptera) in south Florida. As lubbers are confamilial with locusts, we hypothesised that the longitudinal size cline was partly due to density-dependent phase polyphenism. 3. We tested the effect of density, population, and density×population interaction on life-history traits (pronotum length, mass, cumulative development time, growth rate) of, and proportion surviving to, each of the five instars and the adult stage in a 2 × 3 factorial laboratory experiment with two lubber populations, each reared from hatchling to adult at three different densities. 4. The effect of density on life history and survival was independent of the effects of population on life history and survival. Higher densities led to larger adult sizes (pronotum, mass) and lower survivorship. The western population had smaller adult masses, fewer cumulative days to the adult stage, and higher survivorship than the eastern population. 5. Our data suggest that lubber grasshoppers exhibit density-dependent phase polyphenism initiated by the physical presence of conspecifics. However, the plastic response of adult size to density observed in the laboratory is not consistent with the relationship between phenotypes and adult density in the field. Genetic differences between populations observed in the laboratory could contribute to size and life-history differences among lubber populations in the field. [source] Genetic differences in growth of an invasive tree speciesECOLOGY LETTERS, Issue 6 2001Evan Siemann Invasive plants are often more vigorous in their introduced ranges than in their native ranges. This may reflect an innate superiority of plants from some habitats or an escape from their enemies. Another hypothesis proposes that invasive plants evolve increased competitive ability in their introduced range. We present the results of a 14-year common garden experiment with the Chinese Tallow Tree (Sapium sebiferum) from its native range (Asia), place of introduction to North America (Georgia) and areas colonized a century later (Louisiana and Texas). Invasive genotypes, especially those from recently colonized areas, were larger than native genotypes and more likely to produce seeds but had lower quality, poorly defended leaves. Our results demonstrate significant post-invasion genetic differences in an invasive plant species. Post-introduction adaptation by introduced plants may contribute to their invasive success and make it difficult to predict problem species. [source] GEOGRAPHIC VARIATION OF GENETIC AND BEHAVIORAL TRAITS IN NORTHERN AND SOUTHERN TÚNGARA FROGSEVOLUTION, Issue 8 2006Heike Pröhl Abstract We use a combination of microsatellite marker analysis and mate-choice behavior experiments to assess patterns of reproductive isolation of the túngara frog Physalaemus pustulosus along a 550-km transect of 25 populations in Costa Rica and Panama. Earlier studies using allozymes and mitochondrial DNA defined two genetic groups of túngara frogs, one ranging from Mexico to northern Costa Rica (northern group), the second ranging from Panama to northern South America (southern group). Our more fine-scale survey also shows that the northern and southern túngara frogs are genetically different and geographically separated by a gap in the distribution in central Pacific Costa Rica. Genetic differences among populations are highly correlated with geographic distances. Temporal call parameters differed among populations as well as between genetic groups. Differences in calls were explained better by geographic distance than by genetic distance. Phonotaxis experiments showed that females preferred calls of males from their own populations over calls of males from other populations in about two-thirds to three-fourths of the contrasts tested. In mating experiments, females and males from the same group and females from the north with males from the south produced nests and tadpoles. In contrast, females from the south did not produce nests or tadpoles with males from the north. Thus, northern and southern túngara frogs have diverged both genetically and bioacoustically. There is evidence for some prezygotic isolation due to differences in mate recognition and fertilization success, but such isolation is hardly complete. Our results support the general observation that significant differences in sexual signals are often not correlated with strong genetic differentiation. [source] Genetic differences among the LPS biosynthetic loci of serovars of Leptospira interrogans and Leptospira borgpeterseniiFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 1 2001Alejandro de la Peńa-Moctezuma Abstract The gene organization in the lipopolysaccharide biosynthetic (rfb) locus was analyzed in seven Leptospira interrogans serovars within serogroup Icterohemorrhagiae, seven non-Icterohemorrhagiae serovars and one Leptospira borgpetersenii serovar. Two groups of loci were delineated based on DNA hybridization and sequence analysis. Group 1 contained the two Hardjo subtypes, Hardjoprajitno and Hardjobovis. Group 2 (containing Copenhageni, Pomona, Naam, Mwogolo, Smithi, Lai, Canicola, Autumnalis, Pyrogenes, Australis and Icterohemorrhagiae) differed from Group 1 in its organization upstream of orf11, where five ORFs (32, 33, 34, 35, 37) were identified that were not contained in the Group 1 loci. These ORFs encoded a putative epimerase (orf32), a glycosyltransferase (orf33), two integral membrane proteins (orfs 34 and 35), and a galactosyltransferase (orf37). Serovars Australis, Pomona and Autumnalis did not contain orf37. Serovar Bataviae was excluded from the grouping because of its unique genetic organization upstream of orf13. In the Group 2 loci, comparison of the genetic layout at the 5, end revealed differences which included mutations disrupting reading frames in either or both orf34 and orf35 and apparent allelic differences between orf33 homologs that may be sufficient to account for the genetic basis of serovar identity. [source] Genetic influences on behavioral inhibition and anxiety in juvenile rhesus macaquesGENES, BRAIN AND BEHAVIOR, Issue 4 2008J. Rogers In humans and other animals, behavioral responses to threatening stimuli are an important component of temperament. Among children, extreme behavioral inhibition elicited by novel situations or strangers predicts the subsequent development of anxiety disorders and depression. Genetic differences among children are known to affect risk of developing behavioral inhibition and anxiety, but a more detailed understanding of genetic influences on susceptibility is needed. Nonhuman primates provide valuable models for studying the mechanisms underlying human behavior. Individual differences in threat-induced behavioral inhibition (freezing behavior) in young rhesus monkeys are stable over time and reflect individual levels of anxiety. This study used the well-established human intruder paradigm to elicit threat-induced freezing behavior and other behavioral responses in 285 young pedigreed rhesus monkeys. We examined the overall influence of quantitative genetic variation and tested the specific effect of the serotonin transporter promoter repeat polymorphism. Quantitative genetic analyses indicated that the residual heritability of freezing duration (behavioral inhibition) is h2 = 0.384 (P = 0.012) and of ,orienting to the intruder' (vigilance) is h2 = 0.908 (P = 0.00001). Duration of locomotion and hostility and frequency of cooing were not significantly heritable. The serotonin transporter polymorphism showed no significant effect on either freezing or orienting to the intruder. Our results suggest that this species could be used for detailed studies of genetic mechanisms influencing extreme behavioral inhibition, including the identification of specific genes that are involved in predisposing individuals to such behavior. [source] Genetic basis for the psychostimulant effects of nicotine: a quantitative trait locus analysis in AcB/BcA recombinant congenic miceGENES, BRAIN AND BEHAVIOR, Issue 7 2005K. J. Gill Genetic differences in sensitivity to nicotine have been reported in both animals and humans. The present study utilized a novel methodology to map genes involved in regulating both the psychostimulant and depressant effects of nicotine in the AcB/BcA recombinant congenic strains (RCS) of mice. Locomotor activity was measured in a computerized open-field apparatus following subcutaneous administration of saline (days 1 and 2) or nicotine on day 3. The phenotypic measures obtained from this experimental design included total basal locomotor activity, as well as total nicotine activity, nicotine difference scores, nicotine percent change and nicotine regression residual scores. The results indicated that the C57BL/6J (B6) were insensitive to nicotine over the entire dose,response curve (0.1, 0.2, 0.4 and 0.8 mg/kg). However, the 0.8-mg/kg dose of nicotine produced a significant decrease in the locomotor activity in the A/J strain and a wide and continuous range of both locomotor excitation and depression among the AcB/BcA RCS. Single-locus association analysis in the AcB RCS identified quantitative trait loci (QTL) for the psychostimulant effects of nicotine on chromosomes 11, 12, 13, 14 and 17 and one QTL for nicotine-induced depression on chromosome 11. In the BcA RCS, nicotine-induced locomotor activation was associated with seven putative regions on chromosomes 2, 7, 8, 13, 14, 16 and 17. There were no overlapping QTL and no genetic correlations between saline- and nicotine-related phenotypes in the AcB/BcA RCS. A number of putative candidate genes were in proximity to regions identified with nicotine sensitivity, including the ,2 subunit of the nicotinic acetylcholine receptor and the dopamine D3 receptor. [source] The individuality of miceGENES, BRAIN AND BEHAVIOR, Issue 6 2004R. Lathe Mutant mice simulating human CNS disorders are used as models for therapeutic drug development. Drug evaluation requires a coherent correlation between behavioral phenotype and drug status. Variations in behavioral responses could mask such correlations, a problem highlighted by the three-site studies of Crabbe et al. (1999) and Wahlsten et al. (2003a). Factors contributing to variation are considered, focusing on differences between individual animals. Genetic differences due to minisatellite variation suggest that each mouse is genetically distinct. Effects during gestation, including maternal stress, influence later life behavior; while endocrine exchanges between fetus and parent, and between male and female fetuses dependent on intrauterine position, also contribute. Pre and perinatal nutrition and maternal attention also play a role. In adults, endocrine cyclicity in females is a recognized source of behavioral diversity. Notably, there is increasing recognition that groups of wild and laboratory mice have complex social structures, illustrated through consideration of Crowcroft (1966). Dominance status can markedly modify behavior in test paradigms addressing anxiety, locomotion and aggressiveness, to an extent comparable to mutation or drug status. Understanding how such effects amplify the behavioral spectrum displayed by otherwise identical animals will improve testing. [source] Varietal Differences in Development of Maize (Zea mays L.) Seedlings on Compacted SoilsJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 3 2001L. O. Soyelu Differences among open-pollinated tropical maize (Zea mays L.) varieties in seedling development and establishment on compacted soils were studied. Soil dry density was used as an index of compaction. Three soil compaction levels and 12 traits associated with development and establishment of maize seedlings were investigated. A control (without compaction) was also included. Varietal differences were observed for most traits measured. Genetic differences for seedling development on compacted soil were detected. Varietal differences contributed about three times the contribution of compaction to total variability in the traits. Better seedling development and performance were obtained in moderately compacted soil than in the control. Shoot length, shoot dry weight and per cent dry matter in roots were good indicators of the tolerance of maize seedlings to compaction. A physiological strategy for maize seedling establishment on compacted soil was proposed. The implications of the results for seed testing were also highlighted. It was concluded that consideration should be given to the genotype of maize destined for use in ecologies prone to high soil densities. All varieties of maize grown in an agroecological zone could be screened to identify genotypes tolerant of higher soil densities. The seeds could then be multiplied and distributed to farmers. Sortenunterschiede in der Entwicklung von Mais (Zea mays L.)-Sämlingen in verdichteten Böden Sortenunterschiede der Sämlingsentwicklung und des Aufwuchses wurden in verdichteten Böden bei fremdbestäubenden tropischen Mais (Zea mays L.)-Sorten untersucht. Die Bodentrockendichte wurde als Index für die Verdichtung verwendet. Drei Verdichtungsstärken und zwölf Behandlungen im Zusammenhang mit der Entwicklung und dem Anwuchs von Maissämlingen wurden untersucht. Eine Kontrolle (ohne Bodenverdichtung) wurde berücksichtigt. Sortenunterschiede wurden für die meisten Eigenschaften gemessen. Genetische Differenzen der Sämlingsentwicklung in verdichteten Böden konnten beobachtet werden. Sortendifferenzen trugen etwa dreifach im Vergleich zur Bodenverdichtung im Hinblick auf die Gesamtvariabilität der Eigenschaften bei. Bessere Sämlingentwicklung und Sämlingsleistung wurden an moderat verdichteten Böden im Vergleich zur Kontrolle beobachtet. Die Sprosslänge, das Sprosstrockengewicht und die Trockenmasse prozent in Wurzeln gaben gute Hinweise hinsichtlich der Toleranz der Maissämlinge gegenüber Bodenverdichtung. Eine physiologische Strategie für die Maissämlingsentwicklung in verdichteten Böden wird vorgeschlagen. Die Bedeutung der Ergebnisse für Samentestzwecke wurde betont. Es wird angenommen, dass Genotypen für den Anbau in ökologischen Bedingungen, die starke Bodenverdichtungen aufweisen, berücksichtigt werden sollten. Da viele Maissorten in agroökologischen Gebieten angebaut werden, sollten diese getestet werden, um Genotypen mit Toleranz gegenüber stärkerer Bodenverdichtung zu identifizieren. Diese Samen könnten dann vermehrt und an Landwirt abgegeben werden. [source] Genetic diversity measures of the bovine Alberes breed using microsatellites: variability among herds and types of coat colour,JOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 2 2004J. Casellas Summary The Alberes population is a native bovine breed of Catalonia with an unclear origin, which historically some authors have assumed as being composed of two different colour varieties (black and fawn). Sixteen microsatellite loci were analysed, all of them included in the AIRE2066 European Concerted Action list. Overall expected and observed heterozygosities reached values of 0.649 and 0.662, respectively. Genetic differences among black and fawn varieties were not significant (FST = 0.007), and therefore the population is a single variety with a great colour gradation. On the contrary, we detected significant genetic differences among herds (FST = 0.026; p < 0.001), showing a genetic heterogeneity over short geographical distances. The number of migrants per generation among pairs of herds oscillates between 1.46 (Roig and Freixe herds) and 5.62 (Castanyers and Roig herds). Moreover, inbreeding and bottleneck situations can be rejected. The Alberes breed has been grouped within the Cantabrian trunk, closely related to the Asturiana de la Montańa and Alistana breeds, although some other breeds may also have influenced the population along its history. Zusammenfassung Die Rasse Alberes ist eine einheimische Rinderrasse Kataloniens mit unklarer Herkunft, von der historisch einige Autoren vermuten, dass sie eine Zusammensetzung aus zwei verschiedenen Farbvarianten ist (schwarz und hellbraun). Es wurden sechzehn Mikrosatelliten, die alle aus der ,,AIRE2066 European Concerted Action list,, stammen, analysiert. Der gesamte erwartete und beobachtete Heterozygotiegrad erreichte Werte von 0,649 beziehungsweise 0,662. Die genetischen Unterschiede zwischen den schwarzen und hellbraunen Varianten waren nicht signifikant (Fst = 0,007), so dass die Rasse als eine einzige Variante mit einer großen Farbabstufung gilt, die wir erhalten müssen. Im Gegensatz dazu entdeckten wir signifikante genetische Unterschiede innerhalb der Herden (Fst = 0,026, p < 0,001), die eine genetische Heterogenität innerhalb kurzer geografischer Distanzen aufzeigten. Die Anzahl an Migranten pro Generation innerhalb der Herdpaare schwankt zwischen 1,46 (Roig - und Freixe -Herden) und 5,62 (Castanyers - und Roig -Herden). Darüberhinaus kann Inzucht und eine Flaschenhalssituation zurückgewiesen werden. Die Rasse Alberes wurde innerhalb eines Cantabrischen Astes gruppiert, in enger Verwandtschaft zu den Rassen Asturiana de la Montańa und Alistana, obwohl im Laufe der Geschichte auch einige andere Rassen die Population beeinflusst haben könnten. [source] Genetic differences in physiology, growth hormone levels and migratory behaviour of Atlantic salmon smoltsJOURNAL OF FISH BIOLOGY, Issue 1 2001C. Nielsen Out of five strains of Atlantic salmon Salmo salar of 1+ years released upstream of a fyke net in the River Gudenaa in 1996, three, Lagan, Ätran and Corrib, migrated immediately, 50% of the recaptured fish reaching the net in 3,6 days. Burrishoole and Conon fish migrated with a 15,19 day delay. Smolt development in 1997 at the hatchery showed a spring surge in gill Na+, K+ -ATPase activity in all strains which was correlated with increased seawater tolerance. Differences in the timing of gill enzyme development matched the observed migration pattern well. Lagan, Ätran and Corrib strains reached high enzyme activity earlier than the Burrishoole and Conon strains, and strains with delayed enzyme development and migration showed a delayed regression of seawater tolerance compared with the early strains. Inter-strain differences in plasma growth hormone profiles could not be related to the observed patterns of Na+, K+ -ATPase and seawater tolerance development. The study gives evidence of genetic influence on the timing and intensity of smolting and subsequent migration in Atlantic salmon. [source] Genetic differences in oxidative stress and inflammatory responses to diet-induced obesity do not alter liver fibrosis in miceLIVER INTERNATIONAL, Issue 8 2009Wing-Kin Syn Abstract Objective: To determine how genetic factors might influence the progression of nonalcoholic fatty liver disease (NAFLD). Design/Intervention: Beginning in adolescence, male C57BL6 (BL6) and 129/SVJ mice were fed control (n=15/group) or high-fat (HF) diets (n=30/group) for 6 months. Main Outcome Measures: Assessed were body weight, insulin resistance, hepatic production of free radicals, expression of cytokines and fibrosis-related genes and severity of hepatic steatosis, injury and fibrosis. Results: High-fat diets induced comparable obesity, hepatic steatosis and insulin resistance in the two strains. Compared with BL6 mice, 129/SVJ mice had impaired induction of antioxidant genes, generated three- to four-fold more free radicals and exhibited two-fold greater induction of profibrogenic cytokines (interleukin-4 and transforming growth factor-,1) and fibrosis-related genes (fibronectin and tissue inhibitor of metalloproteinase-1) (all P<0.05 for 129 vs BL6). Surprisingly, however, induction of collagen I ,1 mRNA and accumulation of Sirius red-stained fibrils and hepatic hydroxyproline were similar in BL6 and 129/SVJ mice, and although patchy sinusoidal fibrosis emerged in both strains, neither developed bridging fibrosis. Conclusions: Although BL6 and 129/SVJ mice with diet-induced obesity, insulin resistance and steatosis differed with respect to several factors that are thought to influence human NAFLD progression, they developed comparable liver fibrosis. Moreover, none of the risk factors for NAFLD-related cirrhosis in humans, including obesity, insulin resistance, chronic inflammatory and oxidant stress, steatohepatitis or activation of fibrogenic genes, proved to be sufficient to cause cirrhosis in these mice, even when exposure to one or more of these insults was very prolonged. [source] Genetic differences in omega-gliadins involved in two different immediate food hypersensitivities to wheatALLERGY, Issue 8 2007M. Lauričre Background:, Anti-gliadin IgE are expressed in patients with food allergy associated to skin immediate hypersensitivity to hydrolyzed wheat proteins (IHHWP). It is not known if they react with ,5-gliadins, the major allergens in wheat dependant exercise-induced food anaphylaxis (WDEIA), encoded on wheat chromosomes 1B. Methods:, Unmodified gliadins from 14 wheat varieties expressing most of the 1B ,-gliadin alleles, were immunoprobed after SDS-PAGE and blotting, with four sera from patients with IHHWP, and two with WDEIA. Gliadins reacting with IgE were visualized using chemiluminescence and identified according to their mobility and typical SDS-PAGE pattern. The resulting signal was also measured to compare their IgE reactivity. Results:, IHHWP and WDEIA sera exhibited distinct patterns of reactivity. IgE of patients with IHHWP reacted mainly with all ,-gliadins alleles and one ,-gliadin encoded respectively on chromosomes 1D and 1B, but not with any ,5-gliadins alleles as for WDEIA. A few other reactive alleles of ,-gliadins were encoded on chromosomes 1A. Unassigned additional bands of the whole gliadin pattern were also reactive. The four patients with IHHWP exhibited almost the same pattern of reactivity. Main differences concerned band reactivity which modulated the overall reactivity of each wheat variety. Conclusions:, The IgE epitopes involved in IHHWP and WDEIA are different. This suggests that the protein state and the route of exposure to very similar gluten structures, probably orientate the pattern of epitope reactivity and the wheat food allergy manifestations. [source] Genetic differences of rock glaciers and the discontinuous mountain permafrost zone in Kanchanjunga Himal, Eastern NepalPERMAFROST AND PERIGLACIAL PROCESSES, Issue 3 2001Mamoru Ishikawa Abstract A number of rock glaciers, including glacier-derived and talus-derived rock glaciers, were identified in Kanchanjunga Himal, easternmost Nepal. DC resistivity imagings were applied to representative rock glaciers of both types. The distribution of resistivity values in the subsurface within these rock glaciers was significantly different. A massive glacial ice body was found within the glacier-derived rock glacier, suggesting this rock glacier originated from glacial dead ice (ice-cored rock glacier). The lower limits of discontinuous mountain permafrost zone in Kanchanjunga Himal were inferred from the distribution of talus-derived rock glaciers (ice-cemented rock glaciers) and the estimated mean annual air temperature. The lower limit of the discontinuous mountain permafrost zone is 4800 m ASL on the north-facing slopes, while 5300 m ASL on the south- to east-facing slopes. These altitudes were considerably higher than those of the western Himalaya, which are under dry continental climatic conditions. Copyright © 2001 John Wiley & Sons, Ltd. RÉSUMÉ Plusieurs glaciers rocheux comprenant ŕ la fois des formes dérivéees de vrais glaciers et des formes provenant de la mise en mouvement de talus, ont été identifiés dans le Kanchanjunga Himal, dans le Népal le plus oriental. Des images par résistivité DC ont été obtenues pour des glaciers représentatifs des deux catégories. La distribution des valeurs de résistivité en profondeur dans ces glaciers rocheux a été significativement différente. Un corps de glace massif a été trouvé dans le glacier rocheux provenant d'un vrai glacier suggérant qu'il s'agissait de glace morte glaciaire (glacier rocheux ŕ noyau de glace). Les limites inférieures de la zone du pergélisol discontinu dans le Kanchanjungga Himal ont été déduites de la distribution des glaciers rocheux provenant de talus (glaciers rocheux avec de la glace ciment) et d'une estimation de la température moyenne annuelle de l'air. La limite inférieure de la zone du pergélisol discontinu de montagne est de 4800 m d'altitude sur les pentes exposées au nord, tandis que la limite est de 5300 m sur les pentes exposées au sud. Ces altitudes sont considérablement plus élevées que celles de l'ouest de l'Himalaya exposé ŕ des conditions climatiques continentales sčches. Copyright © 2001 John Wiley & Sons, Ltd. [source] Indels within promoter and intron 1 of bovine prion protein gene modulate the gene expression levels in the medulla oblongata of two Japanese cattle breedsANIMAL GENETICS, Issue 2 2010G. Msalya Summary Genetic differences which exist in the prion protein gene (PRNP) have been reported to influence susceptibility of humans, sheep and goats to prion diseases. In cattle, however, none of the known coding polymorphisms has a direct effect on bovine spongiform encephalopathy (BSE). It has been reported that 23-bp insertion/deletion (indel) polymorphisms within the promoter region have a tentative association to BSE susceptibility in German cattle, and a lower number of 24-bp repeat units in the open reading frame (ORF) was reported to reduce BSE susceptibility in transgenic mice. In this study, because of the hypothesis that bovine PRNP promoter polymorphisms cause changes in PRNP expression, we genotyped PRNP polymorphisms in the promoter and intron 1 using 218 genomic DNA samples from two Japanese cattle breeds. We also analysed the expression levels of prion in 40 animals by quantification of real-time PCR using mRNAs extracted from the medulla oblongata to study the relationship between PRNP genotypes and PRNP expression. We found a significant correlation between promoter indel polymorphisms and PRNP -mRNA expression (P0.0413) and therefore hypothesize that differences in polymorphisms could be one of the causes of differences in PRNP expression levels. We also report a novel difference in PRNP expression (P < 0.0001) between Japanese Black and Japanese Brown cattle breeds. There was no significant difference based on age and sex of the animals. [source] Osmotic adjustment of chickpea (Cicer arietinum) is not associated with changes in carbohydrate composition or leaf gas exchange under droughtANNALS OF APPLIED BIOLOGY, Issue 2 2007P.S. Basu Abstract Genetic differences in osmotic adjustment (OA) have been reported among chickpea (Cicer arietinum) cultivars. In this study eight advanced breeding lines (ABLs) derived from a cross between CTS 60543 (high OA) and Kaniva (low OA) and Tyson (medium OA) and Kaniva, along with the parents, were evaluated for OA, leaf carbohydrate composition and leaf gas exchange under dryland field conditions in India. The water potential (WP) decreased to lower values (less than ,2.5 MPa) in Tyson, M 110 and M 86 than in the other genotypes. With decrease in WP, OA increased by 0.5 MPa in Kaniva and CTS 60543 to 1.3 MPa in M 55. As the decrease in WP varied with genotype, when OA was regressed against WP M 39 and M 55 had greater increases in OA with decrease in WP than the remaining nine genotypes, including the parents. As WP decreased, leaf starch content decreased while total soluble sugars, hexoses and sucrose increased: the decrease in starch was much smaller in M 93 and M 129 than in Tyson and M 51, but genotypic differences could not be detected in the increase in total sugars, hexoses or sucrose. The rates of photosynthesis and transpiration decreased as the WP became more negative, but M 129 reached low rates of photosynthesis (2 ,mol m,2 s,1) and transpiration at a WP of ,1.7 MPa, whereas Tyson reached the same low rate at ,2.4 MPa. While OA varied among the chickpea genotypes, the differences were not associated with the changes in carbohydrate composition or the rates of gas exchange at low values of WP. Further, the degree of OA of the 11 genotypes was not the same as when they were selected for differences in OA under rainout shelter conditions in the field in Australia, suggesting that OA may show poor stability depending upon the stress level, location or physiological stage of the plant. This suggests that OA is not a valuable drought-resistance trait to select for in chickpea breeding programmes. [source] Genetic differences in growth among wild populations of the yabby, Cherax destructor (Clark)AQUACULTURE RESEARCH, Issue 12 2002D R Jerry Abstract Before commencing a breeding programme on a new aquaculture species, it is prudent to identify populations or strains with superior characteristics for commercial production. Information on the comparative performance of populations allows informed decisions to be made on the starting genetic base for the programme. As a precursor to a breeding programme in the decapod species, Cherax destructor (Clark), five geographically isolated populations were evaluated for the traits weight at age, abdomen length and abdomen width over a period of 9 months. Mean weight at age was found to vary among the populations by up to 42%, whereas mean abdomen length was similar among four out of the five populations. No differences were found in abdomen width. This study emphasizes that rapid genetic gains can be made simply by starting a breeding programme based on faster growing populations. [source] Ecological correlates of body size in relation to cell size and cell number: patterns in flies, fish, fruits and foliageBIOLOGICAL REVIEWS, Issue 2 2007Jeff Arendt Abstract Body size is important to most aspects of biology and is also one of the most labile traits. Despite its importance we know remarkably little about the proximate (developmental) factors that determine body size under different circumstances. Here, I review what is known about how cell size and number contribute to phenetic and genetic variation in body size in Drosophila melanogaster, several fish, and fruits and leaves of some angiosperms. Variation in resources influences size primarily through changes in cell number while temperature acts through cell size. The difference in cellular mechanism may also explain the differences in growth trajectories resulting from food and temperature manipulations. There is, however, a poorly recognized interaction between food and temperature effects that needs further study. In addition, flies show a sexual dimorphism in temperature effects with the larger sex responding by changes in cell size and the smaller sex showing changes in both cell size and number. Leaf size is more variable than other organs, but there appears to be a consistent difference between how shade-tolerant and shade-intolerant species respond to light level. The former have larger leaves via cell size under shade, the latter via cell number in light conditions. Genetic differences, primarily from comparisons of D. melanogaster, show similar variation. Direct selection on body size alters cell number only, while temperature selection results in increased cell size and decreased cell number. Population comparisons along latitudinal clines show that larger flies have both larger cells and more cells. Use of these proximate patterns can give clues as to how selection acts in the wild. For example, the latitudinal pattern in D. melanogaster is usually assumed to be due to temperature, but the cellular pattern does not match that seen in laboratory selection at different temperatures. [source] Autumnal moth , why autumnal?ECOLOGICAL ENTOMOLOGY, Issue 6 2001Toomas Tammaru Summary 1. As for some other spring-feeding moths, adult flight of Epirrita autumnata (Lepidoptera: Geometridae) occurs in late autumn. Late-season flight is a result of a prolonged pupal period. Potential evolutionary explanations for this phenological pattern are evaluated. 2. In a laboratory rearing, there was a weak correlation between pupation date and the time of adult emergence. A substantial genetic difference in pupal period was found between two geographic populations. Adaptive evolution of eclosion time can thus be expected. 3. Metabolic costs of a prolonged pupal period were found to be moderate but still of some ecological significance. Pupal mortality is likely to form the main cost of the prolonged pupal period. 4. Mortality rates of adults, exposed in the field, showed a declining temporal trend from late summer to normal eclosion time in autumn. Lower predation pressure on adults may constitute the decisive selective advantage of late-season flight. It is suggested that ants, not birds, were the main predators responsible for the temporal trend. 5. Egg mortality was estimated to be low; it is thus unlikely that the late adult period is selected for to reduce the time during which eggs are exposed to predators. 6. In a laboratory experiment, oviposition success was maximal at the time of actual flight peak of E. autumnata, however penalties resulting from sub-optimal timing of oviposition remained limited. [source] The genetic differences with whole genome linkage disequilibrium mapping between responder and non-responder in interferon-, and ribavirin combined therapy for chronic hepatitis C patientsINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 2 2008P.-J. Chen Summary Interferon-, and ribavirin combined therapy has been a mainstream treatment for hepatitis C infection. The efficacy of this combined treatment is around 30% to 60%, and the factors affecting the responsiveness are still poorly defined. Our study is intended to investigate the genetic differences between responder and non-responder patients. The genome-wide linkage disequilibrium screening for loci associated with genetic difference between two patient groups was conducted by using 382 autosomal short tandem repeat (STR) markers involving 92 patients. We have identified 19 STR markers displaying different allele frequencies between the two patient groups. In addition, based on their genomic location and biological function, we selected the CD81 and IL15 genes to perform single nucleotide polymorphism genotyping. In conclusion, this study may provide a new approach for identifying the associated polymorphisms and the susceptible loci for interferon-, and ribavirin combined therapy in patients with chronic hepatitis C. [source] Genetic diversity in pollen beetles (Meligethes aeneus) in Sweden: role of spatial, temporal and insecticide resistance factorsAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 4 2007Nadiya Kazachkova Abstract 1,Pollen beetles Meligethes aeneus are pests of oilseed Brassica crops that are subject to intensive chemical control. Resistance to pyrethroids has been reported. Although this insect is of great economic importance, little is known about its genetic properties and population structure. 2,Amplified fragment length polymorphism (AFLP) analysis with the restriction endonuclease combination EcoRI and PstI was performed on 133 samples of groups of three pollen beetles collected during 2001,04 from five different provinces of Sweden. Both susceptible and resistant insects were studied. Using one primer combination, more than 450 polymorphic DNA fragments were obtained and, in total, four primer combinations were used for analysis. A subsample of 59 single beetles was analysed using one primer combination. 3,AFLP profiles were analysed by similarity measures using the Nei and Li coefficient and Neighbour-joining dendrograms were generated. The dendrogram built using 133 samples showed three distinct groups, each containing beetles representing one generation. Statistical analysis using analysis of molecular variance of single beetle samples showed no evidence of significant genetic difference between resistant and susceptible beetles. Instead, a clear difference between samples, depending on time of collection and generation, was observed. 4,The expected regional population structure, although statistically significant, explained little of the variation. The levels of genetic variation within populations were very high. There appears to be a high rate of gene flow between pollen beetle populations. The implications of this in the context of insecticide resistance are discussed. [source] Population genetics of the endangered limpet Patella ferruginea (Gastropoda: Patellidae): taxonomic, conservation and evolutionary considerationsJOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 1 2006F. Espinosa Abstract The limpet Patella ferruginea is the most endangered marine invertebrate in the western Mediterranean rocky shores, whereas Patella caerulea is the most common Mediterranean limpet. From Pleistocene to historic age, P. ferruginea was distributed around the whole Mediterranean basin, since the shells of this species are a characteristic feature of Palaeolithic and Neolithic deposits in this area. However, its Mediterranean range has progressively contracted to a few restricted areas. The ancient origin of the species (18 Ma) and the present geographical isolation among relic populations could have led to a great genetic difference among populations, taking into account the supposedly low dispersal ability of the species. However, we have observed a few genetic differences among populations and a ,star phylogeny' of COI haplotypes from the 41 individuals of P. ferruginea analysed; a similar pattern has also been observed for the seven individuals of P. caerulea studied. Genetic evidences show a possible bottleneck event on late Pleistocene that affected the two species. The results have an important implication on the future management of this endangered species. Additionally, two different morphological types of P. ferruginea have been described by Payraudeau in 1826: lamarcki and rouxi forms. Clear morphological differences occur between these two types and some authors pointed out the hypothesis about the existence of two different species. The results of the present study conclude that the two different forms of P. ferruginea are ecotypes, rather than different species or subspecies, and intermediate steps are an ecological range instead of hybridization events among different species. Resumen Patella ferruginea es el invertebrado marino más amenazado de las costas del Mediterráneo occidental, mientras que Patella caerulea es una especie muy común. Desde el Pleistoceno hasta épocas históricas, P. ferruginea estuvo distribuída alrededor de toda la cuenca mediterránea, ya que su concha es característica de depósitos paleolíticos y neolíticos en esta área. Sin embargo, su rango de distribución se ha visto reducido a unas pocas áreas restringidas. Su orígen primitivo (18 Ma) y el presente aislamiento geográfico entre las poblaciones podría haber generado importantes diferencias genéticas inter-poblacionales, teniendo en cuenta la supuesta baja capacidad de dispersión de la especie. Sin embargo, se han observado pocas diferencias genéticas inter-poblacionales y una ,,filogenia en estrella'' de los haplotipos de la COI procedentes de los 41 individuos de P. ferruginea analizados, un patrón similar ha sido también observado para los 7 individuos de P. caerulea estudiados. Las evidencias genéticas sugieren un posible cuello de botella a finales del Pleistoceno que afectó a las dos especies. Estos resultados tienen gran importancia en la futura gestión de esta especie amenazada. Adicionalmente, Payraudeau en 1826 describió dos tipo morfológicos de P. ferruginea: formas rouxi y lamarcki. Importantes diferencias morfológicas aparecen entre las dos formas y algunos autores han seńalado la hipótesis de que podrían ser dos especies distintas. Los resultados del presente estudio concluyen que las dos formas de P. ferruginea son ecotipos en lugar de especies o subespecies distintas, y que las formas intermedias serían parte de un rango ecológico en lugar de ser fenómenos de hibridación entre especies diferentes. [source] Ecological, morphological and genetic divergence of sympatric North Atlantic killer whale populationsMOLECULAR ECOLOGY, Issue 24 2009ANDREW D. FOOTE Abstract Ecological divergence has a central role in speciation and is therefore an important source of biodiversity. Studying the micro-evolutionary processes of ecological diversification at its early stages provides an opportunity for investigating the causative mechanisms and ecological conditions promoting divergence. Here we use morphological traits, nitrogen stable isotope ratios and tooth wear to characterize two disparate types of North Atlantic killer whale. We find a highly specialist type, which reaches up to 8.5 m in length and a generalist type which reaches up to 6.6 m in length. There is a single fixed genetic difference in the mtDNA control region between these types, indicating integrity of groupings and a shallow divergence. Phylogenetic analysis indicates this divergence is independent of similar ecological divergences in the Pacific and Antarctic. Niche-width in the generalist type is more strongly influenced by between-individual variation rather than within-individual variation in the composition of the diet. This first step to divergent specialization on different ecological resources provides a rare example of the ecological conditions at the early stages of adaptive radiation. [source] Difference in physiogenomics between male and female infertilityANDROLOGIA, Issue 3 2008V. Wiwanitkit Summary Infertility is an important condition in reproductive medicine. According to this work, there is only one identified physiogenomic relationship on chromosome 5 (CAMK4) for male but there are four identified physiogenomic relationships on chromosome 12 (CD9), chromosome 19 (BSG), chromosome 2 (ADCY3) and chromosome 4 (AFP). Although it has been determined for a long time, there is no clear cut genetic difference between male and female infertility. Systemic approach on the pathophysiology and genomics might provide useful information to better understand the pathogenesis of infertility. In this work, physiogenomics analysis for infertility in male and female was performed. [source] Joining the Pillars of Hercules: mtDNA Sequences Show Multidirectional Gene Flow in the Western MediterraneanANNALS OF HUMAN GENETICS, Issue 4 2003S. Plaza Summary Phylogenetic analysis of mitochondrial DNA (mtDNA) performed in Western Mediterranean populations has shown that both shores share a common set of mtDNA haplogroups already found in Europe and the Middle East. Principal co-ordinates of genetic distances and principal components analyses based on the haplotype frequencies show that the main genetic difference is attributed to the higher frequency of sub-Saharan L haplogroups in NW Africa, showing some gene flow across the Sahara desert, with a major impact in the southern populations of NW Africa. The AMOVA demonstrates that SW European populations are highly homogeneous whereas NW African populations display a more heterogeneous genetic pattern, due to an east-west differentiation as a result of gene flow coming from the East. Despite the shared haplogroups found in both areas, the European V and the NW African U6 haplogroups reveal the traces of the Mediterranean Sea permeability to female migrations, and allowed for determination and quantification of the genetic contribution of both shores to the genetic landscape of the geographic area. Comparison of mtDNA data with autosomal markers and Y-chromosome lineages, analysed in the same populations, shows a congruent pattern, although female-mediated gene flow seems to have been more intense than male-mediated gene flow. [source] FRACTURES OF THE FEMORAL NECK IN AUSTRALIAN ABORIGINALS AND TORRES STRAIT ISLANDERSAUSTRALIAN JOURNAL OF RURAL HEALTH, Issue 3 2001David J. Macintosh ABSTRACT: The objective was to study patients of Aboriginal and Torres Strait Islander origin who were admitted to Cairns Base Hospital with the diagnosis of femoral neck fracture. An analysis of all 232 admissions with this diagnosis between November 1997 and July 2000 was carried out. Information was gathered from data accumulated on the Clinical Pathways database; other local data was also considered. Patients registered as being of Aboriginal and Torres Strait Islander origin have a lower incidence of these fractures than might be expected on an overall population basis, but similar rates on age-standardised data. The female age profile is substantially older than the female non-indigenous osteoporotic fracture group. Indigenous females develop osteoporotic type fractures of the femoral neck at a later age than do non-indigenous females. This may reflect a genetic difference in bone mineral density or a healthy lifestyle in earlier days. Further research is suggested. [source] Neutral markers mirror small-scale quantitative genetic differentiation in an avian island populationBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2009ERIK POSTMA We still know remarkably little about the extent to which neutral markers can provide a biologically relevant description of population structure. In the present study, we address this question, and quantify microsatellite differentiation among a small, structured island population of great tits (Parus major), and a large mainland population 150 km away. Although only a few kilometres apart, we found small but statistically significant levels of differentiation between the eastern and the western part of the island. On the other hand, there was no differentiation between the western part of the island and the mainland population, whereas the eastern part and the mainland did differ significantly. This initially counterintuitive result provides powerful support for the hypothesis that the large genetic difference in clutch size between both parts of the island found earlier is maintained by different levels of gene flow into both parts of the island, and illustrates the capacity of microsatellites to provide a meaningful description of population structure. Importantly, because the level of microsatellite differentiation is very low, we were unable to infer any population structure without grouping individuals a priori. Hence, these low levels of differentiation in neutral markers could easily remain undetected, or incorrectly be dismissed as biologically irrelevant. Thus, although microsatellites can provide a powerful tool to study genetic structure in wild populations, they should be used in conjunction with a range of other sources of information, rather than as a replacement. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 867,875. [source] Annexin VII as a Novel Marker for Invasive Phenotype of Malignant MelanomaCANCER SCIENCE, Issue 1 2000Tatsuki R. Kataoka Both F10 and BL6 sublines of B16 mouse melanoma cells are metastatic after intravenous injection, but only BL6 cells are metastatic after subcutaneous injection. While examining the genetic difference between the two sublines, we found a marked reduction of annexin VII expression in BL6 cells. In addition, fusion cell clones of both sublines, were as poorly metastatic as F10 cells after subcutaneous injection, and contained the annexin VII message as abundantly as F10 cells. Hence, we examined whether the annexin VII expression was correlated with the less malignant phenotype of clinical cases by immunohistochemistry. Immunoreactivities to anti-annexin VII antibody in melanoma cells were evaluated quantitatively by using skin mast cells as an internal positive control. Eighteen patients with malignant melanoma were divided into two groups: lymph node metastasis-negative and positive groups. The ratio of numbers of patients positive versus negative to the antibody was significantly larger in the former than in the latter group. These results not only indicated that annexin VII serves as a marker for less invasive phenotype of malignant melanoma, but also suggested a possible role of annexin VII in tumor suppression. [source] Gastrointestinal Bacterial Transmission among Humans, Mountain Gorillas, and Livestock in Bwindi Impenetrable National Park, UgandaCONSERVATION BIOLOGY, Issue 6 2008INNOCENT B. RWEGO ecología de enfermedades; Escherichia coli; primates; salud del ecosistema; zoonosis Abstract:,Habitat overlap can increase the risks of anthroponotic and zoonotic pathogen transmission between humans, livestock, and wild apes. We collected Escherichia coli bacteria from humans, livestock, and mountain gorillas (Gorilla gorilla beringei) in Bwindi Impenetrable National Park, Uganda, from May to August 2005 to examine whether habitat overlap influences rates and patterns of pathogen transmission between humans and apes and whether livestock might facilitate transmission. We genotyped 496 E. coli isolates with repetitive extragenic palindromic polymerase chain reaction fingerprinting and measured susceptibility to 11 antibiotics with the disc-diffusion method. We conducted population genetic analyses to examine genetic differences among populations of bacteria from different hosts and locations. Gorilla populations that overlapped in their use of habitat at high rates with people and livestock harbored E. coli that were genetically similar to E. coli from those people and livestock, whereas E. coli from gorillas that did not overlap in their use of habitats with people and livestock were more distantly related to human or livestock bacteria. Thirty-five percent of isolates from humans, 27% of isolates from livestock, and 17% of isolates from gorillas were clinically resistant to at least one antibiotic used by local people, and the proportion of individual gorillas harboring resistant isolates declined across populations in proportion to decreasing degrees of habitat overlap with humans. These patterns of genetic similarity and antibiotic resistance among E. coli from populations of apes, humans, and livestock indicate that habitat overlap between species affects the dynamics of gastrointestinal bacterial transmission, perhaps through domestic animal intermediates and the physical environment. Limiting such transmission would benefit human and domestic animal health and ape conservation. Resumen:,El traslape de hábitats puede incrementar los riesgos de transmisión de patógenos antroponótica y zoonótica entre humanos, ganado y simios silvestres. Recolectamos bacterias Escherichia coli de humanos, ganado y gorilas de montańa (Gorilla gorilla beringei) en el Parque Nacional Bwindi Impenetrable, Uganda, de mayo a agosto 2005 para examinar sí el traslape de hábitat influye en las tasas y patrones de transmisión de patógenos entre humanos y simios y sí el ganado facilita esa transmisión. Determinamos el genotipo de 496 aislados de E. coli con marcaje de reacción en cadena de polimerasa palindrómica extragénica (rep-PCR) y medimos la susceptibilidad a 11 antibióticos con el método de difusión de disco. Realizamos análisis de genética poblacional para examinar las diferencias genéticas entre poblaciones de bacterias de huéspedes y localidades diferentes. Las poblaciones de gorilas con alto grado de traslape en el uso de hábitat con humanos y ganado presentaron E. coli genéticamente similar a E. coli de humanos y ganado, mientras que E. coli de gorilas sin traslape en el uso hábitat con humanos y ganado tuvo relación lejana con las bacterias de humanos y ganado. Treinta y cinco porciento de los aislados de humanos, 27% de los aislados de ganado y 17% de los aislados de gorilas fueron clínicamente resistentes a por lo menos un antibiótico utilizado por habitantes locales, y la proporción de gorilas individuales con presencia de aislados resistentes declinó en las poblaciones proporcionalmente con la disminución en el grado de traslape con humanos. Estos de patrones de similitud genética y resistencia a antibióticos entre E. coli de poblaciones de simios, humanos y ganado indican que el traslape de hábitat entre especies afecta la dinámica de transmisión de bacterias gastrointestinales, probablemente a través de animales domésticos intermediarios y el ambiente físico. La limitación de esa transmisión beneficiaría a la salud de humanos y animales domésticos y a la conservación de simios. [source] Pharmacogenomics in Cardiovascular MedicineDRUG DEVELOPMENT RESEARCH, Issue 3 2004John F. Carlquist Abstract The completion of the Human Genome Project (HGP) holds promise for further insight into how genetic differences contribute to an individual's response to a medicine(s). Even before the completion of the HGP, cardiovascular medicine was thrust into the arena of pharmacogenomics by the observation that many drugs, cardiovascular and noncardiovascular, promote cardiac arrhythmias. It is now recognized that these adverse responses as well as beneficial responses to cardiovascular medicines can be influenced by alterations in the genes for metabolizing enzymes, drug transporters, and drug targets. To the present, much basic information regarding gene,drug interactions has accumulated, but translation to clinical care has been slow. It is anticipated that the pace of clinical cardiovascular pharmacogenomics will increase as the result of better-designed studies and technological advances. The final adoption of this area of investigation into clinical practice will also be influenced by financial, psychosocial, and legal factors. Drug Dev. Res. 62:180,190, 2004. © 2004 Wiley-Liss, Inc. [source] Population structure and migratory directions of Scandinavian bluethroats Luscinia svecica, a molecular, morphological and stable isotope analysisECOGRAPHY, Issue 1 2008Olof Hellgren Many species of birds show evidence of secondary contact zones and subspeciation in their Scandinavian distribution range, presumably resulting from different post-glacial recolonization routes. We investigated whether this is the case also in the Scandinavian bluethroat Luscinia svecica, a species that has been suggested to consist of two separate populations: one SW-migrating and long-winged (L. s. gaetkei) breeding in southern Norway, and one shorter-winged ESE-migrating (L. s. svecica) in northern Scandinavia. We sampled males at eleven breeding sites from southern Norway to northernmost Sweden. There were no morphological differences or latitudinal trends within the sample, neither were there any genetic differences or latitudinal trends as measured by variation in AFLP and microsatellite markers. Stable isotope ratios of throat feathers moulted on the wintering grounds showed no, or possibly marginal differences between birds from southern Norway and northern Sweden. We also re-measured old museum skins that in previous studies were classified as L. s.gaetkei, and found marginally longer wings in birds from the southern part of the Scandinavian breeding range. The difference, however, was much smaller than proposed in earlier studies. We conclude that there is no evidence of a genetic population structure among Scandinavian bluethroats that would suggest the presence of a zone of secondary contact. Finally we discuss whether the presumed subspecies gaetkei ever existed. [source] | |||||||||||||||||||||||||||||||||||||||||||