Perfect genetic correlation between number of offspring and grandoffspring in an industrialized human population

Zietsch, Brendan P., Kuja-Halkola, Ralf, Wallum, Hasse and Verweij, Karin J. H. (2014) Perfect genetic correlation between number of offspring and grandoffspring in an industrialized human population. Proceedings of the National Academy of Sciences, 111 3: 1032-1036. doi:10.1073/pnas.1310058111


Author Zietsch, Brendan P.
Kuja-Halkola, Ralf
Wallum, Hasse
Verweij, Karin J. H.
Title Perfect genetic correlation between number of offspring and grandoffspring in an industrialized human population
Journal name Proceedings of the National Academy of Sciences   Check publisher's open access policy
ISSN 0027-8424
1091-6490
Publication date 2014-01-21
Sub-type Article (original research)
DOI 10.1073/pnas.1310058111
Open Access Status DOI
Volume 111
Issue 3
Start page 1032
End page 1036
Total pages 5
Place of publication Washington, DC, United States
Publisher National Academy of Sciences
Language eng
Formatted abstract
Reproductive success is widely used as a measure of fitness. However, offspring quantity may not reflect the genetic contribution to subsequent generations if there is nonrandom variation in offspring quality. Offspring quality is likely to be an important component of human fitness, and tradeoffs between offspring quantity and quality have been reported. As such, studies using offspring quantity as a proxy for fitness may yield erroneous projections of evolutionary change, for example if there is little or no genetic variance in number of grandoffspring or if its genetic variance is to some extent independent of the genetic variance in number of offspring. To address this, we performed a quantitative genetic analysis on the reproductive history of 16,268 Swedish twins born between 1915 and 1929 and their offspring. There was significant sex limitation in the sources of familial variation, but the magnitudes of the genetic and environmental effects were the same in males and females. We found significant genetic variation in number of offspring and grandoffspring (heritability = 24% and 16%, respectively), and genetic variation in the two variables completely overlapped—i.e., there was a perfect genetic correlation between number of offspring and grandoffspring. Shared environment played a smaller but significant role in number of offspring and grandoffspring; again, there was a perfect shared environmental correlation between the two variables. These findings support the use of lifetime reproductive success as a proxy for fitness in populations like the one used here, but we caution against generalizing this conclusion to other kinds of human societies.

Significance Reproductive success (offspring quantity) is widely used as a measure of fitness (genetic contribution to future generations). Accurate predictions of the direction and magnitude of evolutionary change using this measure depend on the untested assumption that the genes influencing number of offspring are the same as those influencing number of grandoffspring. Using a population sample of identical and nonidentical Swedish twins and their descendants, we show that the genetic influences on number of offspring and grandoffspring are identical, supporting the use of reproductive success as a measure of fitness in comparable human populations.
Keyword Fertility
Fecundity
Children
Grandchildren
Selection
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2015 Collection
School of Psychology Publications
 
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Created: Sun, 26 Jan 2014, 02:32:58 EST by Mr Brendan Zietsch on behalf of School of Psychology