Do Monozygotic Twins Have Higher Genetic Quality than Dizygotic Twins and Singletons? Hints from Attractiveness Ratings and Self-Reported Health
Evolutionary theories generally concur that sexual reproduction and genetic recombination evolved to maximize genetic variability. Thus, the existence of monozygotic (MZ) twins, which do not take advantage of genetic recombination for each offspring, poses a puzzle. Evolutionary logic of inclusive fitness suggests that parents with high-quality genes may be more likely to produce MZ twins. Analyses of data from the National Longitudinal Study of Adolescent to Adult Health show that MZ twins were significantly more physically attractive and healthier than dizygotic (DZ) twins and singletons. These results suggest that MZ twins may possess higher-quality genes than DZ twins and singletons, and support one of the first evolutionary theories of MZ twinning that specifies its ultimate functions.
KeywordsTwin research Monozygotic twin conception Add Health
We thank Typhaine Christiaen, Scott Forbes, and David Haig for their comments on earlier drafts.
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Conflict of interest
The authors declare that they have no conflict of interest.
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