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Phenotypic Correlations (phenotypic + correlation)
Selected AbstractsConfirmation of Correlations and Common Quantitative Trait Loci Between Neurotensin Receptor Density and Hypnotic Sensitivity to EthanolALCOHOLISM, Issue 12 2001V. Gene Erwin Background: In previous studies, genetic correlations were observed between hypnotic sensitivity to ethanol and high-affinity neurotensin receptor (NTS1) binding. Provisional quantitative trait loci (QTLs) were identified for these traits, and some of these QTLs were found on common chromosomal regions. In continued efforts to examine the relationship between NTS1 binding capacity and hypnotic sensitivity to ethanol, studies were designed to confirm correlations between NTS1 densities in the brain, duration of ethanol-induced loss of righting reflex (LORR), and blood ethanol concentrations at regain of righting reflex (BECRR). Another purpose of the study was to confirm QTLs for these traits. Methods: ILS X ISS F 2 mice and HAS X LAS F 2 rats as well as the progenitors were tested for LORR, BECRR, and NTS1 densities. Phenotypic correlations were calculated between LORR and BECRR and between these measures and NTS1 densities in striatum from both mice and rats. The F 2 mice were genotyped by using polymorphic markers for five previously reported QTLs for LORR to confirm QTLs for BECRR and NTS1 densities in striatum, ventral midbrain, and frontal cortex. Results: Phenotypic correlations were found between LORR and BECRR (r=,0.66 to ,0.74, p < 10,9) and between these measures and NTS1 densities in striatum (r= 0.28,0.38, p < 10,2) from both mice and rats. QTLs for LORR and BECRR (lod score = 2,6) were found in common regions of chromosomes 1, 2, and 15. By using the combined results from a previous LSXSS RI study and the current results, a suggestive QTL (lod score = 3.1) for striatal NTS1 receptor densities was found on chromosome 15 at approximately 60 cM, in the same region as the chromosome 15 LORR/BECRR QTL. Conclusions: The results are in agreement with previously reported correlations and QTLs for NTS1 receptor densities and measures of hypnotic sensitivity to ethanol in mice and extend those correlations to another species, the rat. These findings support a role for NTS1 in genetically mediated differences in hypnotic sensitivity to ethanol. [source] Vascular gene expression and phenotypic correlation during differentiation of human embryonic stem cellsDEVELOPMENTAL DYNAMICS, Issue 2 2005Sharon Gerecht-Nir Abstract The study of the cascade of events of induction and sequential gene activation that takes place during human embryonic development is hindered by the unavailability of postimplantation embryos at different stages of development. Spontaneous differentiation of human embryonic stem cells (hESCs) can occur by means of the formation of embryoid bodies (EBs), which resemble certain aspects of early embryos to some extent. Embryonic vascular formation, vasculogenesis, is a sequential process that involves complex regulatory cascades. In this study, changes of gene expression along the development of human EBs for 4 weeks were studied by large-scale gene screening. Two main clusters were identified,one of down-regulated genes such as POU5, NANOG, TDGF1/Cripto (TDGF, teratocarcinoma-derived growth factor-1), LIN28, CD24, TERF1 (telomeric repeat binding factor-1), LEFTB (left,right determination, factor B), and a second of up-regulated genes such as TWIST, WNT5A, WT1, AFP, ALB, NCAM1. Focusing on the vascular system development, genes known to be involved in vasculogenesis and angiogenesis were explored. Up-regulated genes include vasculogenic growth factors such as VEGFA, VEGFC, FIGF (VEGFD), ANG1, ANG2, TGF,3, and PDGFB, as well as the related receptors FLT1, FLT4, PDGFRB, TGF,R2, and TGF,R3, other markers such as CD34, VCAM1, PECAM1, VE-CAD, and transcription factors TAL1, GATA2, and GATA3. The reproducibility of the array data was verified independently and illustrated that many genes known to be involved in vascular development are activated during the differentiation of hESCs in culture. Hence, the analysis of the vascular system can be extended to other differentiation pathways, allocating human EBs as an in vitro model to study early human development. Developmental Dynamics 232:487,497, 2005. © 2004 Wiley-Liss, Inc. [source] Leaf herbivory and nutrients increase nectar alkaloidsECOLOGY LETTERS, Issue 8 2006Lynn S. Adler Abstract Correlations between traits may constrain ecological and evolutionary responses to multispecies interactions. Many plants produce defensive compounds in nectar and leaves that could influence interactions with pollinators and herbivores, but the relationship between nectar and leaf defences is entirely unexplored. Correlations between leaf and nectar traits may be mediated by resources and prior damage. We determined the effect of nutrients and leaf herbivory by Manduca sexta on Nicotiana tabacum nectar and leaf alkaloids, floral traits and moth oviposition. We found a positive phenotypic correlation between nectar and leaf alkaloids. Herbivory induced alkaloids in nectar but not in leaves, while nutrients increased alkaloids in both tissues. Moths laid the most eggs on damaged, fertilized plants, suggesting a preference for high alkaloids. Induced nectar alkaloids via leaf herbivory indicate that species interactions involving leaf and floral tissues are linked and should not be treated as independent phenomena in plant ecology or evolution. [source] SEXUAL SELECTION AND IMMUNE FUNCTION IN DROSOPHILA MELANOGASTEREVOLUTION, Issue 2 2008Kurt A. McKean The evolution of immune function depends not only on variation in genes contributing directly to the immune response, but also on genetic variation in other traits indirectly affecting immunocompetence. In particular, sexual selection is predicted to trade-off with immunocompetence because the extra investment of resources needed to increase sexual competitiveness reduces investment in immune function. Additional possible immunological consequences of intensifying sexual selection include an exaggeration of immunological sexual dimorphism, and the reduction of condition-dependent immunological costs due to selection of ,good genes' (the immunocompetence handicap hypothesis, ICHH). We tested for these evolutionary possibilities by increasing sexual selection in laboratory populations of Drosophila melanogaster for 58 generations by reestablishing a male-biased sex ratio at the start of each generation. Sexually selected flies were larger, took longer to develop, and the males were more sexually competitive than males from control (equal sex ratio) lines. We found support for the trade-off hypothesis: sexually selected males were found to have reduced immune function compared to control males. However, we found no evidence that sexual selection promoted immunological sexual dimorphism because females showed a similar reduction in immune function. We found no evidence of evolutionary changes in the condition-dependent expression of immunocompetence contrary to the expectations of the ICHH. Lastly, we compared males from the unselected base population that were either successful (IS) or unsuccessful (IU) in a competitive mating experiment. IS males showed reduced immune function relative to IU males, suggesting that patterns of phenotypic correlation largely mirror patterns of genetic correlation revealed by the selection experiment. Our results suggest increased disease susceptibility could be an important cost limiting increases in sexual competitiveness in populations experiencing intense sexual selection. Such costs may be particularly important given the high intersex correlation, because this represents an apparent genetic conflict, preventing males from reaching their sexually selected optimum. [source] Bivariate association analyses for the mixture of continuous and binary traits with the use of extended generalized estimating equationsGENETIC EPIDEMIOLOGY, Issue 3 2009Jianfeng Liu Abstract Genome-wide association (GWA) study is becoming a powerful tool in deciphering genetic basis of complex human diseases/traits. Currently, the univariate analysis is the most commonly used method to identify genes associated with a certain disease/phenotype under study. A major limitation with the univariate analysis is that it may not make use of the information of multiple correlated phenotypes, which are usually measured and collected in practical studies. The multivariate analysis has proven to be a powerful approach in linkage studies of complex diseases/traits, but it has received little attention in GWA. In this study, we aim to develop a bivariate analytical method for GWA study, which can be used for a complex situation in which continuous trait and a binary trait are measured under study. Based on the modified extended generalized estimating equation (EGEE) method we proposed herein, we assessed the performance of our bivariate analyses through extensive simulations as well as real data analyses. In the study, to develop an EGEE approach for bivariate genetic analyses, we combined two different generalized linear models corresponding to phenotypic variables using a seemingly unrelated regression model. The simulation results demonstrated that our EGEE-based bivariate analytical method outperforms univariate analyses in increasing statistical power under a variety of simulation scenarios. Notably, EGEE-based bivariate analyses have consistent advantages over univariate analyses whether or not there exists a phenotypic correlation between the two traits. Our study has practical importance, as one can always use multivariate analyses as a screening tool when multiple phenotypes are available, without extra costs of statistical power and false-positive rate. Analyses on empirical GWA data further affirm the advantages of our bivariate analytical method. Genet. Epidemiol. 2009. © 2008 Wiley-Liss, Inc. [source] Heritability of human cranial dimensions: comparing the evolvability of different cranial regionsJOURNAL OF ANATOMY, Issue 1 2009Neus Martínez-Abadías Abstract Quantitative craniometrical traits have been successfully incorporated into population genetic methods to provide insight into human population structure. However, little is known about the degree of genetic and non-genetic influences on the phenotypic expression of functionally based traits. Many studies have assessed the heritability of craniofacial traits, but complex patterns of correlation among traits have been disregarded. This is a pitfall as the human skull is strongly integrated. Here we reconsider the evolutionary potential of craniometric traits by assessing their heritability values as well as their patterns of genetic and phenotypic correlation using a large pedigree-structured skull series from Hallstatt (Austria). The sample includes 355 complete adult skulls that have been analysed using 3D geometric morphometric techniques. Heritability estimates for 58 cranial linear distances were computed using maximum likelihood methods. These distances were assigned to the main functional and developmental regions of the skull. Results showed that the human skull has substantial amounts of genetic variation, and a t -test showed that there are no statistically significant differences among the heritabilities of facial, neurocranial and basal dimensions. However, skull evolvability is limited by complex patterns of genetic correlation. Phenotypic and genetic patterns of correlation are consistent but do not support traditional hypotheses of integration of the human shape, showing that the classification between brachy- and dolicephalic skulls is not grounded on the genetic level. Here we support previous findings in the mouse cranium and provide empirical evidence that covariation between the maximum widths of the main developmental regions of the skull is the dominant factor of integration in the human skull. [source] Phenotypic and genetic variation in emergence and development time of a trimorphic damselflyJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2005J. ABBOTT Abstract Although colour polymorphisms in adult organisms of many taxa are often adaptive in the context of sexual selection or predation, genetic correlations between colour and other phenotypic traits expressed early in ontogeny could also play an important role in polymorphic systems. We studied phenotypic and genetic variation in development time among female colour morphs in the polymorphic damselfly Ischnura elegans in the field and by raising larvae in a common laboratory environment. In the field, the three different female morphs emerged at different times. Among laboratory-raised families, we found evidence of a significant correlation between maternal morph and larval development time in both sexes. This suggests that the phenotypic correlation between morph and emergence time in the field has a parallel in a genetic correlation between maternal colour and offspring development time. Maternal colour morph frequencies could thus potentially change as correlated responses to selection on larval emergence dates. The similar genetic correlation in male offspring suggests that sex-limitation in this system is incomplete, which may lead to an ontogenetic sexual conflict between selection for early male emergence (protandry) and emergence times associated with maternal morph. [source] Relationship between obesity, adipocytokines, and blood pressure: Possible common genetic and environmental factorsAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 1 2009Ia Pantsulaia Adipokines may link adipose tissue to the inflammatory, metabolic, and immune dysregulation. The variation of adipokine levels within individuals, intercorrelations, and relationships to well-established measures of adiposity are incompletely defined. The main goal of the present study was quantitative evaluation of the genetic interrelationships between obesity and adipokines in normal human population. The study sample comprised 272 families of various sizes, including 530 men and 531 women aged 18,80 years, randomly recruited in rural population living in Russia. Various fatness and fat distribution measures (OB), blood pressure (BP), and plasma levels of several adipokines (AC), such as adiponectin, leptin, resistin, and IGFBP-1, have been measured. The likelihood ratio tests clearly revealed that genetic effect for all studied phenotypes was highly significant (P < 0.001) and accounted for 45.9% ± 8.1%, 33.7% ± 7.9%, 35.7% ± 9.8% of variation for AC, OB, and BP, respectively. The pairwise bivariate analyses showed that strong phenotypic correlation between the obesity (OB) and adipocytokines (AC) was caused by both common genetic and environmental factors (rG = 0.597 ± 0.116, rE = 0.671 ± 0.051). The phenotypic correlation between BP and OB is explained by shared genetic factors only (rG = 0.532 ± 0.109), whereas the phenotypic correlation between BP and AC has only common environment basis (rE = ,0.212 ± 0.081) and was mostly due to the correlation observed in females. Our results suggest that genetic factors play a significant role in regulation of variation of the examined traits. The variation of OB traits is almost fully due to genes influencing variation of AC, whereas the correlation between BP and AC is only marginally significant and caused only by shared environment. Am. J. Hum. Biol., 2009. © 2008 Wiley-Liss, Inc. [source] Artificial spawning of European catfish Silurus glanis L.: differences between propagation results after stimulation of ovulation with carp pituitary and OvopelAQUACULTURE RESEARCH, Issue 1 2001E Brzuska Abstract The effect of spawning on European catfish females with an average body weight of 5.6 kg and 11.2 kg was investigated, with carp pituitary and Ovopel being used as ovulation stimulators. Ovopel induced ovulation in a higher percentage of females of both smaller and larger body weight. The applied ovulation stimulators did not significantly affect the weight of the obtained eggs. On the other hand, the effect of the stimulators was highly significant (P,,0.01) with respect to the percentage of live embryos after 24-, 48- and 56-h incubation. The fish of greater body weight yielded eggs of a significantly (P,,0.05) greater weight, although of poorer quality. The interaction between the ovulation stimulator and female body weight was statistically significant (P,,0.05) for the weight of the obtained eggs and highly significant (P,,0.01) for the percentage of live embryos after 48-h incubation. For the percentage of live embryos after 24- and 56-h incubation, the statistical significance (P,,0.05) of this interaction was determined. In the case of females of smaller body weight, a statistically significant (P,,0.05) phenotypic correlation was found between the percentage of live embryos after 24-h incubation and that after 48-h incubation, and also between the percentage of live embryos after 24- and 56-h incubation. [source] Lamotrigine Therapy of Epilepsy in Tuberous SclerosisEPILEPSIA, Issue 7 2001David Neal Franz Summary: ,Purpose: Lamotrigine (LTG), a newer antiepileptic drug (AED), has activity against both partial-onset and generalized seizures. Its reported benefits for behavior, and its effectiveness in Lennox,Gastaut syndrome and other forms of refractory epilepsy, make it a logical choice for treatment of epilepsy in tuberous sclerosis complex (TSC). We present our experience with LTG therapy of epilepsy in 57 patients with TSC. Methods: Patients fulfilled the diagnostic criteria for clinically definite TSC. LTG was initiated and increased until improvement in seizure frequency was noted, intolerable side effects occurred, or maximal doses were reached. Seizure frequency and behavioral changes were recorded during LTG therapy and compared with those prior to the introduction of LTG. Results: Twenty-four (42%) were seizure free, and 21 (37%) had a >50% reduction in seizure frequency. Eighteen (32%) had subjectively improved behavior and/or alertness with daily activities. Thirty-eight (67%) had no change in this regard, whereas one (2%) became worse. Responders were more likely to not have a history of infantile spasms, and to have experienced only partial seizures (p < 0.05). Otherwise no phenotypic correlations with response were apparent. Conclusions: Among patients with TSC and epilepsy, LTG was effective and well tolerated, including as initial monotherapy. Improved alertness and behavior were apparent in many patients. The incidence of side effects is similar to that reported for other pediatric populations with symptomatic partial epilepsy. The usefulness of LTG in TSC may relate to an underlying defect of glutamatergic neurotransmission in partial epilepsy. [source] Sex differences in genetic and environmental determinants of pulse pressureGENETIC EPIDEMIOLOGY, Issue 5 2006Katrina J. Scurrah Abstract Pulse pressure (PP) is an independent risk factor for cardiovascular disease. PP rises with age, more so in women. We examined sex differences in the correlations and variance components of PP in adult subjects from 767 nuclear families, enriched with those containing twins, from the Victorian Family Heart Study. After adjusting for age, we found no significant differences in the means or variances of PP in males and females. Under the assumption of no sex differences, the proportions of variance due to shared genes, shared environment, and individual-specific environment were 20%, 23% and 57%, respectively. However, same-sex relative pairs had significantly higher correlations than opposite-sex pairs (P=0.005), implying the existence of sex-dependent effects. Extensions to the simple variance components model suggested three possible explanations for these differences: smaller genetic correlation between opposite-sex pairs (,G,MF=0.45, P=0.007); smaller environmental correlation between opposite-sex pairs (P=0.0003); or different environmental and genetic correlations obtained by estimating genetic, environmental, and individual variance components separately for males and females (not nested, Akaike's Information Criterion (AIC) smaller by 6.69). Under the last model, the genetic component of PP variance is greater for males (1.62 vs 0.33) while the environmental component is greater for females (1.84 vs 0), which would have implications for the planning of gene discovery studies, since heritability would be higher in males. However, the second (environmental) approach best fits the data according to the AIC. Genetic explanations for sex differences in phenotypic correlations may be misleading unless shared environmental factors are also considered. PP illustrates a phenotype in which sex dependency represents an important component of phenotypic determination that can be revealed by detailed variance components modelling. Genet. Epidemiol. 2006. © 2006 Wiley-Liss, Inc. [source] Relevance of the genes for bone mass variation to susceptibility to osteoporotic fractures and its implications to gene search for complex human diseasesGENETIC EPIDEMIOLOGY, Issue 1 2002Hong-Wen Deng Abstract We investigate the relevance of the genetic determination of bone mineral density (BMD) variation to that of differential risk to osteoporotic fractures (OF). The high heritability (h2) of BMD and the significant phenotypic correlations between high BMD and low risk to OF are well known. Little is reported on h2 for OF. Extensive molecular genetic studies aimed at uncovering genes for differential risks to OF have focussed on BMD as a surrogate phenotype. However, the relevance of the genetic determination of BMD to that of OF is unknown. This relevance can be characterized by genetic correlation between BMD and OF. For 50 Caucasian pedigrees, we estimated that h2 at the hip is 0.65 (P < 0.0001) for BMD and 0.53 (P < 0.05) for OF; however, the genetic correlation between BMD and OF is nonsignificant (P > 0.45) and less than 1% of additive genetic variance is shared between them. Hence, most genes found important for BMD may not be relevant to OF at the hip. The phenotypic correlation between high BMD and low risk to OF at the hip (approximately ,0.30) is largely due to an environmental correlation (,E = ,0.73, P < 0.0001). The search for genes for OF should start with a significant h2 for OF and should include risk factors (besides BMD) that are genetically correlated with OF. All genes found important for various risk factors must be tested for their relevance to OF. Ideally, employing OF per se as a direct phenotype for gene hunting and testing can ensure the importance and direct relevance of the genes found for the risk of OF. This study may have significant implications for the common practice of gene search for complex diseases through underlying risk factors (usually quantitative traits). Genet. Epidemiol. 22:12,25, 2002. © 2002 Wiley-Liss, Inc. [source] Application of REML procedure to estimate the genetic parameters of weekly liveweights in one-to-one sire and dam pedigree recorded Japanese quailJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 1 2003M. Saatci Summary Residual maximum likelihood procedure was applied to analyse data from a one-to-one pedigreed Japanese quail population, using an animal model to estimate the genetic parameters of weekly liveweights. Records of 1108 animals from 113 sires and 152 dams were analysed. An individual animal model was used. The heritabilities of weights for hatching (HW) with their standard errors (SE), week 1 (W1), week 2 (W2), week 3 (W3), week 4 (W4), week 5 (W5) and week 6 (W6) were 0.51 ± 0.05, 0.32 ± 0.06, 0.20 ± 0.05, 0.21 ± 0.06, 0.20 ± 0.05, 0.15 ± 0.04 and 0.14 ± 0.04, respectively. The strongest genetic correlations were found between W1 and W3 (0.98 ± 0.11). Generally, genetic correlations were higher than the phenotypic correlations. The highest phenotypic correlation (0.85) was between the W4 and W5 weights. Strong genetic correlations among the weekly weights suggest that selection for W5 or W6 weight may be based on weights recorded earlier. Zusammenfassung Die Anwendung der REML-Methode zur Schätzung von genetischen Parametern für Wochengewichte bei japanischen Wachteln mit Abstammungsinformationen Die REML-Methode zur Varianzkomponentenschätzung mittels eines Tiermodells wurde für eine Population von japanischen Wachteln mit Abstammungsinformationen für Wochengewichte angewandt. Daten von 1108 Tieren von 113 Vätern und 152 Müttern wurden mit einem Tiermodell analysiert. Folgende Heritabilitäten wurden geschätzt: 0,51 ± 0,05 für Schlupfgewicht (HW), 0,32 ± 0,06 für Gewicht 1. Woche (W1), 0,20 ± 0,05 für Gewicht 2. Woche (W2), 0,21 ± 0,06 für Gewicht 3. Woche (W3), 0,20 ± 0,05 für Gewicht 4. Woche (W4), 0,15 ± 0,04 für Gewicht 5. Woche (W5) und 0,14 ± 0,04 für Gewicht 6. Woche (W6). Die höchste genetischen Korrelation wurde zwischen W1 und W3 gefunden (0,98 ± 0,11). Generell waren die genetischen Korrelationen höher als die phänotypischen. Die höchste phänotypische Korrelation (0,85) wurde zwischen den Gewichten in der 4. und 5. Woche beobachtet. Die hohen genetischen Korrelationen führen zu der Konsequenz, dass auf die Gewichte der 5. und 6. Woche selektiert werden kann unter Nutzung der früheren Wochengewichte. [source] Estimation of genetic parameters of type traits in Asturiana de los Valles beef cattle breedJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 2 2002J. P. GUTIÉRREZ Ten type traits and a final score were analysed in 5868 records of the Asturiana de los Valles beef cattle breed. Traits were grouped into two classes: (i) traits scoring skeletal and muscular development and (ii) traits scoring adjustment to the breed standard. Heritabilities were moderate to low, ranging from 0.04 to 0.26. Genetic correlations among traits were, in general, in the same direction as, but higher than, phenotypic correlations. The genetic variability shown, in general, for the analysed traits would justify the inclusion of morphological assessment in the Asturiana de los Valles beef cattle breed sire selection programme. Main characteristics of the current type classification system are criticized. The knowledge of (co)variances among type and economically important productive and reproductive traits is recommended before revision of the classification methodology. Schätzung genetischer Parameter für Exterieurmerkmale in der Asturiana de los Valles Fleischrinderrasse 5868 registrierte Asturiana de los Valles Tiere wurden bezüglich 10 Exterieurmerkmalen und eines Gesamtwertes auf der Basis einer gewichteten Berücksichtigung dieser Einzelmerkmale untersucht. Die Merkmale wurden in zwei Klassen unterteilt: (i) Merkmale, die Skelett- und Muskelentwicklung betreffen und (ii) rassespezifische Merkmale. Die Heritabilitäten lagen zwischen 0,04 und 0,26. Genetische Korrelationen zwischen den Merkmalen waren allgemein mit den phänotypischen Korrelationen gleichgerichtet, aber mit höheren Werten. Die aufgezeigte genetische Variabilität der untersuchten Merkmale würde deren Eingliederung in die morphologische Bewertung im Rahmen des Asturiana de los Valles Fleischrinder Selektionsprogrammes für Bullen rechtfertigen. Wichtige Charakteristika der gegenwärtigen Exterieurbeurteilung werden kritisiert. Es wird empfohlen erst (Ko-)varianzen zwischen Exterieur und ökonomisch wichtigen Produktions- und Reproduktionsmerkmalen zu ermitteln, bevor die Bewertungsmethodik überarbeitet wird. [source] Apparent inferiority of first-time breeders in the kittiwake: the role of heterogeneity among age classesJOURNAL OF ANIMAL ECOLOGY, Issue 3 2000Emmanuelle Cam Summary 1.,Many studies have provided evidence that first-time breeders have a lower survival, a lower probability of success, or of breeding, in the following year. Hypotheses based on reproductive costs have often been proposed to explain this. However, because of the intrinsic relationship between age and experience, the apparent inferiority of first-time breeders at the population level may result from selection, and experience may not influence performance within each individual. In this paper we address the question of phenotypic correlations between fitness components. This addresses differences in individual quality, a prerequisite for a selection process to occur. We also test the hypothesis of an influence of experience on these components while taking age and reproductive success into account: two factors likely to play a key role in a selection process. 2.,Using data from a long-term study on the kittiwake, we found that first-time breeders have a lower probability of success, a lower survival and a lower probability of breeding in the next year than experienced breeders. However, neither experienced nor inexperienced breeders have a lower survival or a lower probability of breeding in the following year than birds that skipped a breeding opportunity. This suggests heterogeneity in quality among individuals. 3.,Failed birds have a lower survival and a lower probability of breeding in the following year regardless of experience. This can be interpreted in the light of the selection hypothesis. The inferiority of inexperienced breeders may be linked to a higher proportion of lower-quality individuals in younger age classes. When age and breeding success are controlled for, there is no evidence of an influence of experience on survival or future breeding probability. 4.,Using data from individuals whose reproductive life lasted the same number of years, we investigated the influence of experience on reproductive performance within individuals. There is no strong evidence that a process operating within individuals explains the improvement in performance observed at the population level. [source] Normal and Abnormal Personality Traits: Evidence for Genetic and Environmental Relationships in the Minnesota Study of Twins Reared ApartJOURNAL OF PERSONALITY, Issue 5 2002Kristian E. Markon ABSTRACT Recent studies have demonstrated substantial correlations between normal and abnormal personality traits. Yet little is known about how these correlations are mediated genetically and environmentally: Do normal and abnormal personality traits stem from the same underlying genes and environments? We addressed this question using data from 128 monozygotic and dizygotic twin pairs in the Minnesota Study of Twins Reared Apart (MISTRA). Additive genetic and nonshared environmental correlations between scales of the Minnesota Multiphasic Personality Inventory (MMPI),an index of abnormal personality,and the Multidimensional Personality Questionnaire (MPQ),an index of normal personality,were estimated. Results indicated that phenotypic correlations between normal and abnormal personality were mediated by genetic as well as environmental factors, although the magnitude of genetic mediation tended to be larger overall. Moreover, the patterns of phenotypic, genetic, and environmental relationships among the scales were similar, suggesting that influences on normal and abnormal personality act through systems common to both. It is suggested that future research focus on the neurogenetic substrates of these shared systems and how dysfunction in these systems influences development of disordered personality. [source] Identification of QTLs affecting adaptive traits in Castanea sativa MillPLANT CELL & ENVIRONMENT, Issue 9 2004M CASASOLI ABSTRACT A QTL analysis for three different adaptive traits was performed in an F1 progeny of Castanea sativa Mill. The female and male parents originated from two Turkish chestnut populations adapted to a drought and humid environment, respectively. QTLs for bud flush, growth and carbon isotope discrimination were detected over a 3-year period. Bud set was also recorded in the last year of measurement. Thirty-five individual QTLs were detected for phenology, 28 for growth and 17 for carbon isotope discrimination, most of them explaining a low to moderate proportion of the total phenotypic variance. QTLs were distributed throughout the whole genome. Temporally stable QTLs were identified for all the traits analysed, with phenology showing the higher proportion of stable QTLs. Interesting phenotypic correlations and co-localizations among QTLs for different adaptive traits were observed, allowing the formulation of an hypothesis about the genetic adaptation of the female parent to drought. [source] Genetic dissection of cotton physiological responses to arid conditions and their inter-relationships with productivityPLANT CELL & ENVIRONMENT, Issue 3 2004Y. SARANGA ABSTRACT Testing of the extent to which different complex traits share common genetic control provides a means to distinguish associations that are truly diagnostic of genetic potential for improved adaptation to abiotic stress, from incidental phenotypic correlations. In two generations of progeny from a cross between Gossypium hirsutum and Gossypium barbadense, quantitative trait loci (QTL) mapping was used to evaluate correspondence in genetic control of selected physiological measures and productivity under water-limited and well-watered environments, respectively. A total of 33 QTLs were detected for five physiological variables [osmotic potential (OP), carbon isotope ratio (,13C; indicator of water use efficiency), canopy temperature, chlorophyll a and b], and 46 QTLs for five measures of crop productivity [dry matter, seed cotton yield (SC), harvest index, boll weight, and boll number]. QTL likelihood intervals for high SC and low OP corresponded in three genomic regions, two of which mapped to homoeologous locations on the two subgenomes of tetraploid cotton. QTLs for ,13C showed only incidental association with productivity, indicating that high water use efficiency can be associated with either high or low productivity. Different cotton species have evolved different alleles related to physiological responses and productivity under water deficit, which may permit the development of genotypes that are better-adapted to arid conditions. [source] Genetic covariation in production traits of sub-adult black bream Acanthopagrus butcheri after grow-outAQUACULTURE RESEARCH, Issue 11 2005Robert G Doupé Abstract Predicting the suitability and reliability of traits associated with juvenile growth as indirect selection criteria for choosing future broodstock requires accurate and repeatable estimates of genetic (co)variation for growth traits at different ages. We compared juvenile wet weight of black bream Acanthopagrus butcheri (Munro) at 6 months of age with wet weight, dressed weight, fillet yield and gonad weight in tagged individuals at 18 months of age, following 12 months of farm grow-out. Fish survival and tag retention was high, and there was significant among-family variation for all traits. The phenotypic correlations among wet weight, dressed weight and fillet yield at 18 months of age were very high (0.93,0.97) and similar to their genetic correlations (0.96). Importantly, the phenotypic correlations between wet weight at 6 months and wet weight, dressed weight and fillet yield at 18 months were high (0.63,0.65), and so too were their genetic correlations (0.66,0.73), indicating the potential for using wet weight in the hatchery as a selection criterion for improved weight and meat yield of fish at harvest. Gonad weight shared little or no phenotypic or genetic correlation with these other traits, suggesting that selection for faster growing fish will not affect fecundity or sexual maturation rate. It appears, however, that cultured black bream do become sexually mature more rapidly than wild fish, as 78% of all fish harvested in this study had developing or mature gonads, whereas less than 50% of fish in wild populations are reproductively mature by the same age. Precocious sexual development may lead to uncontrolled spawning in grow-out ponds and a potential loss of selection gains. [source] | |||||||||||||