Genetic basis of response to 50 generations of selection on body weight in inbred mice.
A long-established inbred strain of mice was divergently selected for body weight for 50 generations. Selection of new mutations affecting the trait eventually led to a divergence of approximately three phenotypic standard deviations between the high and low lines. Heritability for body weight increased at a rate between 0.23% and 0.57% per generation from new mutations, depending on the genetic model assumed. About two-thirds of the selection response was in the upward direction. The response was episodic, suggesting a substantial contribution from the selection of mutations with large effects on the trait. A maximum likelihood procedure was used to estimate the number of factors contributing to the response using data from line crosses, with models of n equivalent gene effects (i.e., to estimate the Wright-Castle index), or n genes with variable effects. The results of the analysis of data from a cross between the selected high line and an unselected control line indicated that two major factors were involved, with the suggestion of an additional minor factor.
Keightley
P D
PD
Institute of Cell, Animal and Population Biology, University of Edinburgh, Scotland. p.keightley@edinburgh.ac.uk
D000367:Age Factors; D000818:Animals; D001835:Body Weight / Q000235:genetics*; D005260:Female; D007178:Inbreeding; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D009154:Mutation; D012641:Selection, Genetic