Last updated April 17, 2018 at 11:11 am
Researchers have found that men have an indirect genetic effect on the reproductive timing of their female partners.
A woman’s genes can influence the age she becomes a mother, but a new study, which looks at 400 years of records from two Swiss villages, suggests her partner’s can also play a big role.
For the study, researchers looked at parish data from 1578 to 1977, and took into consideration birth, marriages and deaths of individuals, as well as socio-economic status and natal environment.
A classical model of women’s reproductive timing (not taking her partner into account) suggests that about 13 per cent is down to genetics. When the researchers took into account both partners, the figure rose to around 25 per cent.
They also found that, historically, women married to men with a higher status occupation had their first child at a younger age.
During the later study period, however, women of high socio-economic status entered motherhood later in life.
The researchers admit that this involves sociological changes during modern times that are outside the scope of their study.
Nor does the study take into account modern family lifestyles, which include a wider range away from a nuclear family.
The authors also indicate a lack of knowledge about the reverse effect on men’s own reproductive timing to understand the broader evolutionary dynamics of human reproduction.
Nevertheless, the study shows that there could be a great deal “hidden” genetic variation for women’s reproductive timing.
The authors also note that their study “demonstrates that genealogical databases hold enormous potential, not only for enabling perspectives of the evolutionary dynamics regulating human populations but also for offering insights into biological processes”.
This research is published in the Proceedings of the Royal Society B.
