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Non-additive Genetic Effects (non-additive + genetic_effects)
Selected AbstractsAdditive genetic and other sources of variation in growth traits of juvenile black bream Acanthopagrus butcheriAQUACULTURE RESEARCH, Issue 7 2005Robert G Doupé Abstract We used a factorial mating design to estimate the contribution of additive genetic, non-additive genetic and maternal effects to variation in growth traits of black bream Acanthopagrus butcheri (Munro) at 75, 130 and 180 days of age in the hatchery. Maternal genetic and environmental effects were greatest at 75 days of age, accounting for 9.1% of total phenotypic variance in wet weight, 11.4% of variance in standard length and 8.8% of variance in total length. At later ages maternal effects were much reduced, explaining 0.8,3.7% of phenotypic variance in growth traits. Additive genetic effects were greatest at 130 days of age, when they accounted for 17.4% of total phenotypic variance in wet weight, 21.4% of variance in standard length and 18.7% of variance in total length. Additive genetic effects were negligible (<1%) at 75 days of age and 4.8,5.5% of total phenotypic variance in growth traits at 180 days of age. Non-additive genetic effects (which also included common environmental effects because of families being raised in the same tank) explained 5.8,7.3% of total phenotypic variance in growth traits at 75 days of age, but were much smaller at later ages. Variable stocking densities among tanks up to 75 days significantly affected all growth trait measurements below 180 days of age. [source] Mate Choice for Genetic Benefits: Time to Put the Pieces TogetherETHOLOGY, Issue 1 2010Attila Hettyey It is thought that mate choice allows individuals to obtain genetic benefits for their offspring, and although many studies have found some support for this hypothesis, several critical questions remain unresolved. One main problem is that empirical studies on mate choice and genetic benefits have been rather piecemeal. Some studies (1) aimed to test how mate choice affects offspring fitness, but have not examined whether the benefits are because of genetic effects. Other studies tested whether mate choice provides (2) additive or (3) non-additive genetic benefits and only a few studies (4) considered these genetic effects together. Finally, some studies (5) examined whether the potential benefits that might be gained from mate choice are due to additive genetic effects vs. non-additive effects, and although they found evidence for both, they did not examine whether mate choice is relevant. Furthermore, previous studies have usually not controlled for non-genetic sources of variation in offspring fitness. Thus, there remain gaping holes in our understanding, and it is the connections among the research approaches that now need more attention. We suggest that studies are needed that measure non-genetic effects, the potential benefits from both additive and non-additive genetic effects, and also determine whether mate choice exploits these potential benefits. Such integrative studies are necessary to put the pieces together and clarify the role of genetic benefits in the evolution of mate choice. [source] Computing simplifications for non-additive genetic modelsJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 6 2003L. R. Schaeffer Summary A limiting factor in the analysis of non-additive genetic models has been the ability to compute the inverses of non-additive genetic covariance matrices for large populations. Also, the order of the equations was equal to the number of animals times the number of non-additive genetic effects that were included in the model. This paper describes a computing algorithm that avoids the inverses of the non-additive genetic covariance matrices and keeps the size of the equations to be the same as any animal model with only additive genetic effects. Quadratic forms for the non-additive genetic variances could also be computed without the inverses of the non-additive genetic covariance matrices. Zusammenfassung In der Analyse von nicht additiven genetischen Modellen war der limitierende Faktor die Fähigkeit Inversen der Matrizen nicht additiver genetischer Kovarianzen in großen Populationen zu berechnen. Auch die Reihenfolge der Gleichungen war gleich zu der Anzahl der Tiere mal der Anzahl der nicht additiven genetischen Effekte, die im Model berücksichtigt wurden. Diese Veröffentlichung beschreibt einen Berechnungsalgorithmus, der die Umkehrung der Matrizen nicht additiver genetischer Kovarianzen umgeht und die Gleichungen auf der selben Größe hält wie ein Tiermodel mit additiven genetischen Effekten. Auch quadratische Formen für nicht additive genetische Kovarianzen können ohne die Umkehrung der Matrizen nicht additiver genetischer Kovarianzen berechnet werden. [source] Heterotic effects for yield and tuber solids and type of gene action for five traits in 4x potato families derived from interploid (4x-2x) crossesPLANT BREEDING, Issue 2 2000J. A. Buso Abstract The degree of heterosis for total tuber yield (TTY) and total solids (TS) in 4x-2x crosses was estimated by comparing the performance of 12 families with their respective parents in two locations in Wisconsin (USA). The parental 2x clones were Phureja-haploid Tuberosum hybrids with 2n -pollen production by first-division restitution. The general combining ability (GCA) and specific combining ability (SCA) were estimated for TTY, TS, vine maturity (VM), length of tuber sprout dormancy (LD), and tuber eye depth (ED). Family performance for TTY ranged from 74 to 146% at Hancock (E#1) and from 77 to 287 at Rhinelander (E#2) when compared with that of the 4x parent group. For VM, the families were late maturing, but a few precocious ones were identified. For TS, the families had heterosis of 5.1% over the 4x parent group. The families had slightly higher ED values than the 4x parents, but families with values within the commercial range were identified. The family average for LD (54 days) was closer to the 2x group (51 days) than to the 4x group (88 days). The direction and magnitude of the parent-family relationships were variable. The 4x parent TTY was correlated with progeny in E#1 but not E#2. The 2x parent VM had correlation with the offspring at E#2 but not at E#1. The type of gene action had a trait-specific expression. Significant SCA and GCA variances were observed, suggesting that additive as well as non-additive genetic effects were operating. The 4x-2x crosses were able to generate heterotic families for TTY and TS in combination with other useful traits. However, no promising results were found for LD because of the apparent dominance of the short-dormancy phenotype. This result indicates the need of additional selection and breeding efforts for some specific traits when using S. phureja -derived germplasm. [source] | ||||||||||