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Genetic variation within and among animal populations

Published online by Cambridge University Press:  27 February 2018

W.G. Hill
Affiliation:
Institute of Cell, Animal and Population Biology, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JT, UK
X.-S. Zhang
Affiliation:
Institute of Cell, Animal and Population Biology, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JT, UK
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Abstract

Factors that influence variability between and within populations at levels ranging from the molecular to quantitative traits are reviewed. For quantitative traits, models of how levels of variation are determined and how they change have to be based on simplifying assumptions. At its simplest, variation is maintained by a balance between gain by mutation and loss by sampling due to finite population size. Rates of response in commercial breeding programmes and long-term selection experiments are reviewed. It is seen that rates of progress continue to be high in farmed livestock, but not in race horses, and that continuing responses have been maintained for 100 generations in laboratory experiments. Hence variability can be maintained over long periods despite intense selection in populations of limited size. The potential role of conserved populations is reviewed, and it is suggested that their role is unlikely to be as a useful source of variation in commercial populations but mainly to preserve our culture and to fill particular niches.

Type
Section 2: Quantitative and molecular genetic basis for conservation
Copyright
Copyright © British Society of Animal Science 2004

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