Comparative losses of quantitative and molecular genetic variation in finite populations of Drosophila melanogaster

Dean M. Gilligan, David A. Briscoe, Richard Frankham*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

49 Citations (Scopus)
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Quantitative genetic variation, the main determinant of the ability to evolve, is expected to be lost in small populations, but there are limited data on the effect, and controversy as to whether it is similar to that for near neutral molecular variation. Genetic variation for abdominal and sternopleural bristle numbers and allozyme heterozygosity were estimated in 23 populations of Drosophila melanogaster maintained at effective population sizes of 25, 50, 100, 250 or 500 for 50 generations, as well as in 19 highly inbred populations and the wild outbred base population. Highly significant negative regressions of proportion of initial genetic variation retained on inbreeding due to finite population size were observed for both quantitative characters (b=-0.67±0.14 and -0.58±0.11) and allozyme heterozygosity (b=-0.79±0.10), and the regression coefficients did not differ significantly. Thus, quantitative genetic variation is being lost at a similar rate to molecular genetic variation. However, genetic variation for all traits was lost at rates significantly slower than predicted by neutral theory, most likely due to associative overdominance. Positive, but relatively low correlations were found among the different measures of genetic variation, but their low magnitudes were attributed to large sampling errors, rather than differences in the underlying processes of loss.

Original languageEnglish
Pages (from-to)47-55
Number of pages9
JournalGenetical Research
Issue number1
Publication statusPublished - Feb 2005

Bibliographical note

Copyright 2005 Cambridge University Press. Article originally published in Genetical research, vol. 85, iss. 1, pp. 47-55. The original article can be found at

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