Genetic responses in the early years of selection programmes using genetic differences between generations

Hopkins, I. R.; James, J. W.

doi:10.1017/s0003356100023060

Cited by 14 publications

(7 citation statements)

References 6 publications

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“…Hopkins and James [3] studied rates of genetic gain based on contributions of parental age groups to selected offspring in the next cohort. However, true asymptotic proportions of genes are not only affected by selection among the offspring, but also by subsequent rounds of selection [1,6].…”

Section: This Equation Is Identical To the Well-known Results Of Rendementioning

confidence: 99%

“…Therefore, asymptotic proportions of genes that can be calculated using methods in [3] will deviate systematically from true asymptotic proportions. The predicted ∆G of [3] however is valid, as shown by James [4].…”

Section: This Equation Is Identical To the Well-known Results Of Rendementioning

confidence: 99%

“…The product of the long term genetic contribution and the Mendelian sampling term quantifies the impact of an individual on the population mean in the long term. Contrary to equation (1), genetic gain originating from a specific individual or group accumulates over generations in equation (3). The convergence of genetic contributions to their equilibrium values takes several cycles of selection.…”

Section: Another Approachmentioning

confidence: 99%

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On the relation between gene flow theory and genetic gain

Bijma

Woolliams

2000

Genet Sel Evol

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-In conventional gene flow theory the rate of genetic gain is calculated as the summed products of genetic selection differential and asymptotic proportion of genes deriving from sex-age groups. Recent studies have shown that asymptotic proportions of genes predicted from conventional gene flow theory may deviate considerably from true proportions. However, the rate of genetic gain predicted from conventional gene flow theory was accurate. The current note shows that the connection between asymptotic proportions of genes and rate of genetic gain that is embodied in conventional gene flow theory is invalid, even though genetic gain may be predicted correctly from it. Dans la méthode classique de calcul de la transmission des gènes, le taux de progrès génétique est calculé comme la somme des produits de la différentielle de sélection génétique et de la proportion asymptotique des gènes provenant des groupesâge-sexe. Desétudes récentes ont montré que les proportions asymptotiques de gènes préditesà partir de la méthode classique de calcul des flux de gènes peuvent dévier considérablement des proportions réelles. Par contre, le progrès génétique est prédità partir de cette même méthode avec une bonne précision. La présente note montre que le lien entre le flux des gènes et le progrès génétique, tel qu'il apparaît dans la méthode classique de calcul des flux des gènes n'est donc pas correct, même si le progrès génétique peutêtre correctement prédità partir de ladite méthode.progrès génétique / flux de gènes / génération chevauchante / réponseà la sélection

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Section: This Equation Is Identical To the Well-known Results Of Rendementioning

confidence: 99%

Section: This Equation Is Identical To the Well-known Results Of Rendementioning

confidence: 99%

Section: Another Approachmentioning

confidence: 99%

See 1 more Smart Citation

On the relation between gene flow theory and genetic gain

Bijma

Woolliams

2000

Genet Sel Evol

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“…The build-up of genetic gain over time will therefore not be linear in the early years, particularly for the expression of net reproduction, which is sex-limited (Hi\11974; Hopkins & James 1979).…”

Section: Discussionmentioning

confidence: 99%

Some benefits and costs of genetic improvement in New Zealand's sheep and beef cattle industry

Morris

1980

New Zealand Journal of Experimental Agriculture

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“…where S is the weighted mean selection differential for animals in subpopulation A from sires in A and sires in B (Hopkins and James, 1979).…”

Section: Cumulative Response To Phenotypic Selection With Discrete Gementioning

confidence: 99%

Gene flow and potential selection response in age-structured subpopulations having a common male pool

Rönnegård¹,

Danell²

2001

Anim. Sci.

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In extensive pastoral systems, where mating cannot be controlled, the breeding strategies of intermingling owner flocks interact. We present a method to evaluate a breeding programme in extensive reindeer (Rangifer tarandus) management which can also be applied to other pastoral production systems. Our main objective was to evaluate the method by applying sensitivity analyses. The method included a gene flow model with maternal effects. The potential response Rp was defined as the response that could be achieved in a closed nucleus with a given selection procedure. The value of Rp was derived from the gene flow from dams to daughters, selection differentials, and the realized difference between subpopulations. We studied a population structure having two subpopulations, only one of which had been subjected to selection. Random mating between subpopulations and a common male pool were assumed. A reference case was defined using reindeer data from the literature. After 9 years of continued selection among progeny the estimate of Rp was 7·0 times higher than the realized subpopulation difference. We analysed deviations of Rp from the reference case caused by different female age structures between subpopulations. We also analysed the sensitivity of maternal effects. The method proved insensitive to differences in female age structure between subpopulations but was sensitive to the relative contribution of maternal effects to progeny performance.

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Genetic responses in the early years of selection programmes using genetic differences between generations

Cited by 14 publications

References 6 publications

On the relation between gene flow theory and genetic gain

On the relation between gene flow theory and genetic gain

Some benefits and costs of genetic improvement in New Zealand's sheep and beef cattle industry

Gene flow and potential selection response in age-structured subpopulations having a common male pool

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