Natural selection and quantitative genetics of life-history traits in Western women: A twin study

Kirk, K. M., Blomberg, S. P., Duffy, D. L., Heath, A. C., Owens, I. P. and Martin, N. G. (2001) Natural selection and quantitative genetics of life-history traits in Western women: A twin study. Evolution, 55 2: 423-435. doi:10.1554/0014-3820(2001)055[0423:NSAQGO]2.0.CO;2

Author Kirk, K. M.
Blomberg, S. P.
Duffy, D. L.
Heath, A. C.
Owens, I. P.
Martin, N. G.
Title Natural selection and quantitative genetics of life-history traits in Western women: A twin study
Journal name Evolution   Check publisher's open access policy
ISSN 0014-3820
Publication date 2001-02-01
Sub-type Article (original research)
DOI 10.1554/0014-3820(2001)055[0423:NSAQGO]2.0.CO;2
Volume 55
Issue 2
Start page 423
End page 435
Total pages 13
Place of publication Lawrence, Kansas, USA
Publisher Society for the Study of Evolution
Language eng
Subject C1
321011 Medical Genetics
730107 Inherited diseases (incl. gene therapy)
Abstract Whether contemporary human populations are still evolving as a result of natural selection has been hotly debated. For natural selection to cause evolutionary change in a trait, variation in the trait must be correlated with fitness and be genetically heritable and there must be no genetic constraints to evolution. These conditions have rarely been tested in human populations. In this study, data from a large twin cohort were used to assess whether selection Will cause a change among women in contemporary Western population for three life-history traits: age at menarche, age at first reproduction, and age at menopause. We control for temporal variation in fecundity (the baby boom phenomenon) and differences between women in educational background and religious affiliation. University-educated women have 35% lower fitness than those with less than seven years education, and Roman Catholic women have about 20% higher fitness than those of other religions. Although these differences were significant, education and religion only accounted for 2% and 1% of variance in fitness, respectively. Using structural equation modeling, we reveal significant genetic influences for all three life-history traits, with heritability estimates of 0.50, 0.23, and 0.45, respectively. However, strong genetic covariation with reproductive fitness could only be demonstrated for age at first reproduction, with much weaker covariation for age at menopause and no significant covariation for age at menarche. Selection may, therefore, lead to the evolution of earlier age at first reproduction in this population. We also estimate substantial heritable variation in fitness itself, with approximately 39% of the variance attributable to additive genetic effects, the remainder consisting of unique environmental effects and small effects from education and religion. We discuss mechanisms that could be maintaining such a high heritability for fitness. Most likely is that selection is now acting on different traits from which it did in pre-industrial human populations.
Keyword Ecology
Evolutionary Biology
Genetics & Heredity
Genetic Correlation
Life Histories
Natural Selection
Reproductive Success
Fundamental Theorem
Sexual Selection
Lek Paradox
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
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School of Psychology Publications
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Created: Wed, 15 Aug 2007, 01:11:36 EST