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Same Trait (same + trait)
Selected AbstractsA comparison between multivariate Slash, Student's t and probit threshold models for analysis of clinical mastitis in first lactation cowsJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 5 2006Y-M. Chang Summary Robust threshold models with multivariate Student's t or multivariate Slash link functions were employed to infer genetic parameters of clinical mastitis at different stages of lactation, with each cow defining a cluster of records. The robust fits were compared with that from a multivariate probit model via a pseudo-Bayes factor and an analysis of residuals. Clinical mastitis records on 36 178 first-lactation Norwegian Red cows from 5286 herds, daughters of 245 sires, were analysed. The opportunity for infection interval, going from 30 days pre-calving to 300 days postpartum, was divided into four periods: (i) ,30 to 0 days pre-calving; (ii) 1,30 days; (iii) 31,120 days; and (iv) 121,300 days of lactation. Within each period, absence or presence of clinical mastitis was scored as 0 or 1 respectively. Markov chain Monte Carlo methods were used to draw samples from posterior distributions of interest. Pseudo-Bayes factors strongly favoured the multivariate Slash and Student's t models over the probit model. The posterior mean of the degrees of freedom parameter for the Slash model was 2.2, indicating heavy tails of the liability distribution. The posterior mean of the degrees of freedom for the Student's t model was 8.5, also pointing away from a normal liability for clinical mastitis. A residual was the observed phenotype (0 or 1) minus the posterior mean of the probability of mastitis. The Slash and Student's t models tended to have smaller residuals than the probit model in cows that contracted mastitis. Heritability of liability to clinical mastitis was 0.13,0.14 before calving, and ranged from 0.05 to 0.08 after calving in the robust models. Genetic correlations were between 0.50 and 0.73, suggesting that clinical mastitis resistance is not the same trait across periods, corroborating earlier findings with probit models. [source] Male,male competition, female mate choice and their interaction: determining total sexual selectionJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2009JOHN HUNT Abstract Empirical studies of sexual selection typically focus on one of the two mechanisms of sexual selection without integrating these into a description of total sexual selection, or study total sexual selection without quantifying the contributions of all of the mechanisms of sexual selection. However, this can provide an incomplete or misleading view of how sexually selected traits evolve if the mechanisms of sexual selection are opposing or differ in form. Here, we take a two-fold approach to advocate a direction for future studies of sexual selection. We first show how a quantitative partitioning and examination of sexual selection mechanisms can inform by identifying illustrative studies that describe both male,male competition and female mate choice acting on the same trait. In our sample, the most common trait where this occurred was body size, and selection was typically linear. We found that male,male competition and female mate choice can be reinforcing or opposing, although the former is most common in the literature. The mechanisms of sexual selection can occur simultaneously or sequentially, and we found they were more likely to be opposing when the mechanisms operated sequentially. The degree and timing that these mechanisms interact have important implications for the operation of sexual selection and needs to be considered in designing studies. Our examples highlight where empirical data are needed. We especially lack standardized measures of the form and strength of selection imposed by each mechanism of sexual selection and how they combine to determine total sexual selection. Secondly, using quantitative genetic principles, we outline how the selection imposed by individual mechanisms can be measured and combined to estimate the total strength and form of sexual selection. We discuss the evolutionary consequences of combining the mechanisms of sexual selection and interpreting total sexual selection. We suggest how this approach may result in empirical progress in the field of sexual selection. [source] Quantitative Trait Loci for Panicle Layer Uniformity Identified in Doubled Haploid Lines of Rice in Two EnvironmentsJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 9 2009Liangyong Ma Abstract Uniformity of stem height in rice directly affects crop yield potential and appearance, and has become a vital index for rice improvement. In the present study, a doubled haploid (DH) population, derived from a cross between japonica rice Chunjiang 06 and indica rice TN1 was used to analyze the quantitative trait locus (QTL) for three related traits of panicle-layer-uniformity; that is, the tallest panicle height, the lowest panicle height and panicle layer disuniformity in two locations: Hangzhou (HZ) and Hainan (HN). A total of 16 QTLs for three traits distributed on eight chromosomes were detected in two different environments. Two QTLs, qTPH -4 and qTPH -8 were co-located with the QTLs for qLPH -4 and qLPH -8, which were only significant in the HZ environment, whereas the qTPH -6 and qLPH -6 located at the same interval were only significant in the HN environment. Two QTLs, qPLD -10-1 and qPLD -10-2, were closely linked to qTPH-10, and they might have been at the same locus. One QTL, qPLD -3, was detected in both environments, explaining more than 23% of the phenotypic variations. The CJ06 allele of qPLD -3 could increase the panicle layer disuniformity by 9.23 and 4.74 cm in the HZ and HN environments. Except for qPLD -3, almost all other QTLs for the same trait were detected only in one environment, indicating that these three traits were dramatically affected by environmental factors. The results may be useful for elucidation of the molecular mechanism of panicle-layer-uniformity and marker assisted breeding for super-rice. [source] Relationship Quality, Trait Similarity, and Self-Other Agreement on Personality Ratings in College RoommatesJOURNAL OF PERSONALITY, Issue 1 2003John E. Kurtz Previous research has shown that the level of self-other agreement for personality trait ratings increases with the length of acquaintanceship between the target and the informant. These findings emerge exclusively from studies of well-acquainted pairs in natural relationships and relative strangers interacting in laboratory and classroom settings. The present study examines self-other correlations for trait ratings using the NEO Five Factor Inventory (NEO-FFI; Costa & McCrae, 1992) with 103 pairs of previously unacquainted female college roommates. Assessments were obtained at approximately 2 weeks and again at approximately 15 weeks subsequent to the roommates' initial introduction. Self-other correlations increased for all five NEO-FFI scores and agreement correlations for Conscientiousness were significantly higher than for Extraversion at both occasions. Differences in relationship quality did not moderate self-other agreement for any of the traits. However, better relationship quality was associated with higher other-ratings of Extraversion, Agreeableness, and Conscientiousness and lower other-ratings of Neuroticism after controlling for self-ratings on the same trait. Higher similarity in self-ratings of Neuroticism and Openness was associated with higher self-other agreement for these ratings, and similarity in Conscientiousness was associated with higher relationship quality. These results are considered in light of existing theories of differential trait observability and the effects of unique contexts on trait perception. [source] Pleiotropic effects of environment-specific adaptation in Arabidopsis thalianaNEW PHYTOLOGIST, Issue 3 2009P. X. Kover Summary ,,Local adaptation may be important for the preservation of genetic diversity and the promotion of speciation. However, local adaptation may also constrain establishment in different environments. The consequences of local adaptation depend strongly on the pleiotropic effects of the genes involved in adaptation. ,,Here, we investigated the pleiotropic effects of the genetic response to selection in outbred lines of Arabidopsis artificially selected to flower earlier under both winter- and spring-annual simulated conditions. The consequences of adaptation were evaluated by reciprocally transplanting selected and control lines between the two conditions. ,,Selected lines always flower earlier than their controls, independent of growing conditions. However, selected lines, growing in the same condition in which they were selected, flower earlier than plants selected in the alternative environment. Plants selected to flower earlier in spring produce more fruits than controls when growing in the spring, and less fruits when growing in the winter; indicating that local adaptation has negative pleiotropic effects in another environment. ,,Our results indicate that local adaptation can arise even when selection targets the same trait in the same direction. Furthermore, it suggests that adaptation under the two different environments can generate fitness trade-offs that can maintain genetic variation for flowering time. [source] Genomic dissection of drought resistance in durum wheat × wild emmer wheat recombinant inbreed line populationPLANT CELL & ENVIRONMENT, Issue 7 2009ZVI PELEG ABSTRACT Drought is the major factor limiting wheat productivity worldwide. The gene pool of wild emmer wheat, Triticum turgidum ssp. dicoccoides, harbours a rich allelic repertoire for morpho-physiological traits conferring drought resistance. The genetic and physiological bases of drought responses were studied here in a tetraploid wheat population of 152 recombinant inbreed lines (RILs), derived from a cross between durum wheat (cv. Langdon) and wild emmer (acc# G18-16), under contrasting water availabilities. Wide genetic variation was found among RILs for all studied traits. A total of 110 quantitative trait loci (QTLs) were mapped for 11 traits, with LOD score range of 3.0,35.4. Several QTLs showed environmental specificity, accounting for productivity and related traits under water-limited (20 QTLs) or well-watered conditions (15 QTLs), and in terms of drought susceptibility index (22 QTLs). Major genomic regions controlling productivity and related traits were identified on chromosomes 2B, 4A, 5A and 7B. QTLs for productivity were associated with QTLs for drought-adaptive traits, suggesting the involvement of several strategies in wheat adaptation to drought stress. Fifteen pairs of QTLs for the same trait were mapped to seemingly homoeologous positions, reflecting synteny between the A and B genomes. The identified QTLs may facilitate the use of wild alleles for improvement of drought resistance in elite wheat cultivars. [source] Temperament assessments of lactating cows in three contexts and their applicability as management traitsANIMAL SCIENCE JOURNAL, Issue 6 2004Katsuji UETAKE ABSTRACT The applicability of three behavioral assessments of lactating cows as management traits was verified. Flight responses to an approaching human (flight starting and walking distances, and flight walking speed) at pasture, entrance order into the milking parlour and step-kick behavior to cup attachment were observed for 713 subject cows in six Australasian dairy farms. On all farms, cows were kept at pasture without any barn housing. Flight responses were measured once, and other assessments were recorded repeatedly for each subject cow. A principal component analysis was performed to verify whether these assessments appear to measure the same trait. A two-way anova and correlation analyses were then used to test whether obtained principal components were affected by farm, age and milking stage of cows. Australian and some Japanese herd management systems were compared for flight distance using a one-way anova and a multiple comparison test. Three behavioral assessments clustered in different principal components, indicating that these assessments did not appear to measure the same trait. Factor scores of four principal components were affected by farm (all, P < 0.01), and the scores of principal component 1, interpreted as fear of humans (r = ,0.16, P < 0.01), and component 2, interpreted as aversion to cup attachment (r = ,0.28, P < 0.01), were moderately correlated with age. These results emphasize the necessity of data standardization to reduce the non-genetic variation resulting from these two affectors. The flight distance at pasture of herds in Australia (6.06 ± 2.85 m) was significantly (P < 0.05) different from the flight distances measured in paddocks (1.50 ± 0.82 m) and free-stall barns (1.22 ± 1.09 m) in Japan. However, mean distances were not different between the Australian herds at pasture and the Japanese herds at pasture in tie-stall barns (3.96 ± 2.16 m) or in a free-stall barn (4.03 ± 1.79 m). This difference could be a result of the fact that only a single measurement was made, so that repeated measurement might improve the usefulness of flight distance as a management trait. In conclusion, it was verified that step-kick behavior to cup attachment and flight responses to human approach were, although they have some affectors, applicable as objective management traits in lactating cows. [source] A new HpaII PCR-RFLP within the porcine prolactin receptor (PRLR) gene and study of its effect on litter size and number of teatsJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 1 2002L. PUTNOVÁ DNA polymorphism of the porcine prolactin receptor gene (PRLR) was investigated and used to study its effect on litter size and number of teats in pigs. By means of PRLR gene sequence homology in pig, human and other species, primers were designed for PCR amplification within 5, unknown (to date) part of the prolactin receptor gene in pigs. In this part of the gene, a new polymorphism with HpaII restriction endonuclease was detected. AluI polymorphism described before and our new HpaII polymorphism were used to study the associations with reproduction traits. The PCR restriction fragment length polymorphism (PCR-RFLP) method was used to genotype AluI and HpaII loci of the PRLR gene in line A with 83 sows of Landrace breed and in two lines (B and C) with 75 and 86 Large White sows, respectively. Statistical analysis of 1020 litters showed that AluI locus was associated with litter size mainly in Landrace and affected the first parities, while HpaII locus of the gene was associated with the same traits in Landrace and Large White pigs and mainly affected numbers of weaned of pigs. The magnitude of the effect varied by population with the effects exceeding two pigs per litter in Landrace line and 1 pig per litter in Large White populations. Ein neuer HpaII PCR-RFLP innerhalb des porcinen Prolaktionrezeptorgens (PRLR), und Zusammenhänge zur Wurfgröße und Zitzenzahl DNA-Polymorphismen im porcinen Prolaktionrezeptorgen (PRLR) wurden untersucht und für die Analyse von Einflüssen auf Wurfgröße und Zitzenzahl bei Schweinen verwendet. Auf der Basis der PRLR -Gensequenzhomologie zwischen Schwein, Mensch und anderen Spezies wurden Primer für die PCR-Amplifikation aus dem 5, Bereich des Prolaktionrezeptorgens abgeleitet, der bisher beim Schwein noch unbekannt ist. In diesem Teil des Gens wurde mittels HpaII-Restriktionsendonuklease ein neuer Polymorphismus dargestellt. AluI Polymorphismus und der neue HpaII Polymorphismus wurden für Assoziationsstudien in Bezug auf Reproduktionsmerkmale verwendet. Mittels PCR-RFLP wurden in Linie A 83 Sauen der Landrasse und die Linien B und C mit 75 bzw. 86 Large White Sauen unter Verwendung von AluI und HpaII am PRLR -Gen genotypisiert. Die statistische Analyse von 1.020 Würfen zeigte, dass der AluI-Polymorphismus insbesondere in der Landrasse mit der Wurfgröße assoziiert ist, sowie die ersten Trächtigkeiten beeinflusst, während der HpaII Polymorphismus die gleichen Merkmale in der Landrasse und Large White Schweinen und insbesondere die Zahl an abgesetzten Ferkeln beeinflusste. Die Auswirkungen des Effekts variierten innerhalb Population, wobei der Effekt 2 Ferkel je Wurf in der Landrasse-Linie und 1 Ferkel je Wurf in der Large White Populationen überstieg. [source] Evidence for a combination of pre-adapted traits and rapid adaptive change in the invasive plant Centaurea stoebeJOURNAL OF ECOLOGY, Issue 4 2010Martin L. Henery Summary 1. Introduced plants have the potential to rapidly evolve traits of ecological importance that may add to their innate potential to become invasive. During invasions, selection may favour genotypes that are already pre-adapted to conditions in the new habitat and, over time, alter the characteristics of subsequent generations. 2. Spotted knapweed (Centaurea stoebe) occurs in two predominantly spatially separated cytotypes in its native range (Europe,Western Asia), but currently only the tetraploid form has been confirmed in the introduced range (North America), where it is invasive. We used several common garden experiments to examine, across multiple populations, whether tetraploids and diploids from the native range differ in life cycle, leaf traits and reproductive capacity and if such differences would explain the predominance of tetraploids and their advance into new habitats in the introduced range. We also compared the same traits in tetraploids from the native and introduced range to determine whether any rapid adaptive changes had occurred since introduction that may have enhanced invasive potential of the species in North America. 3. We found tetraploids had lower specific leaf area, less lamina dissection and fewer, narrower leaves than diploids. Diploids exhibited a monocarpic life cycle and produced few if any accessory rosettes. Diploids produced significantly more seeds per capitulum and had more capitula per plant than tetraploids. In contrast, the vast majority of European tetraploids continued to flower in both seasons by regenerating from multiple secondary rosettes, demonstrating a predominantly polycarpic life cycle. 4. During early growth tetraploids from North America achieved greater biomass than both tetraploids and diploids from the native range but this did not manifest as larger above-ground biomass at maturity. In North American tetraploids there was also evidence of a shift towards a more strictly polycarpic life cycle, less leaf dissection, greater carbon investment per leaf, and greater seed production per capitulum. 5.,Synthesis. Our results suggest that the characteristics of tetraploid C. stoebe pre-adapted them (compared to diploid conspecifics) for spread and persistence of the species into habitats in North America characterized by a more continental climate. After the species' introduction, small but potentially important shifts in tetraploid biology have occurred that may have contributed significantly to successful invasion. [source] Functional traits of woody plants: correspondence of species rankings between field adults and laboratory-grown seedlings?JOURNAL OF VEGETATION SCIENCE, Issue 3 2003J.H.C. Cornelissen Castroviejo et al. (1986,2000); Stace (1991) Abstract. Research into interspecific variation in functional traits is important for our understanding of trade-offs in plant design and function, for plant functional type classifications and for understanding ecosystem responses to shifts in species composition. Interspecific rankings of functional traits are a function of, among other factors, ontogenetic or allometric development and environmental effects on phenotypes. For woody plants, which attain large size and long lives, these factors might have strong effects on interspecific trait rankings. This paper is the first to test and compare the correspondence of interspecific rankings between laboratory grown seedlings and field grown adult plants for a wide range of functional leaf and stem traits. It employs data for 90 diverse woody and semiwoody species in a temperate British and a (sub)Mediterranean Spanish flora, all collected according to a strict protocol. For 12 out of 14 leaf and stem traits we found significant correlations between the species ranking in laboratory seedlings and field adults. For leaf size and maximum stem vessel diameter > 50 % of variation in field adults was explained by that in laboratory seedlings. Two important determinants of plant and ecosystem functioning, specific leaf area and leaf N content, had only 27 to 36 and 17 to 31 % of variation, respectively, in field adults explained by laboratory seedlings, owing to subsets of species with particular ecologies deviating from the general trend. In contrast, interspecific rankings for the same traits were strongly correlated between populations of field adults on different geological substrata. Extrapolation of interspecific trait rankings from laboratory seedlings to adult plants in the field, or vice versa, should be done with great caution. [source] Heterosis performance of yield and fibre quality in F1 and F2 hybrids in upland cottonPLANT BREEDING, Issue 3 2004Y. T. Wu Abstract Because of the difficulty of producing F1 hybrid seeds by hand emasculation and pollination, wide use of heterosis in cotton production has been limited in China. The objective of this study was to evaluate the potential of F2 hybrids for yield and fibre quality. A half diallel involving eight parents and their F1 and F2 hybrids was grown in replicated studies at Linqing and Nanjing in 1999 and Nanjing in 2000. Yield and fibre quality was determined for all 64 entries. Fibre quality was also determined for parents and F1s, but only for Zhongmiansuo 28 (ZMS28), Xiangzamian 2 (XZM2) and Wanmian 13 (WM13) F2s. These three F2 hybrids are extensively planted in China and provide experimental controls with which to compare the performance of new hybrids. Average yield heterosis for F1s and F2s was 15.9 and 9.2%, respectively. Inbreeding depression for yield varied but some F2s greatly out-yielded the best variety. Average F1 heterosis was 6.7, 6.2 and 2.9%, respectively for number of bolls per unit area, boll weight, and lint percentage. The average F2 heterosis for the same traits was 4.4, 3.3 and 1.6%, respectively. F1 heterosis for fibre traits was low. In general, parental average was a good indicator of the yield and fibre quality of F1 hybrids. These encouraging results suggest there is sufficient heterosis for yield to use F2s in China. [source] Sperm-limited fecundity and polyandry-induced mortality in female nematodes Caenorhabditis remaneiBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2010S. ANAID DIAZ In many sexually reproducing species, females are sperm limited and actively mate more than once which can lead to sperm competition between males. However, the costs and benefits of multiple matings may differ for males and females leading to different optimal mating frequencies and consequent sexual conflict. Under these circumstances, male traits that reduce females' re-mating rates are likely to evolve. However, the same traits can also reduce, directly or indirectly, female survival and/or manipulate female fecundity. Evidence of this sexual conflict is common across several taxa. Here, we examine the evidence for this form of conflict in the free-living nematodes of the Caenorhabditis genus. Members of this group are extensively used to describe developmental and physiological processes. Despite this, we understand little about the evolution of selfing, maintenance of males and sexual conflict in these species, particularly those with gonochoristic mating strategies. In this study, we demonstrate experimentally sexual conflict in the gonochoristic of C. remanei cultured under laboratory conditions. In our first experiment, we found that female fecundity increased with the number of males present which suggests that females' reproduction may be sperm limited. However, increasing the number of males present also reduced female survival. A second experiment ruled out the alternative explanation of density-dependent reduction in female survival when more males were present as increasing female density correspondingly did not affect female survival. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99, 362,369. [source] | ||||||||||||||||||||||