Department of Social Research, University of Turku, Finland.
J Biosoc Sci. 2021 Nov;53(6):968-971. doi: 10.1017/S0021932020000711. Epub 2020 Dec 7.
Evolutionary theory posits that grandmothers can increase their inclusive fitness by investing time and resources in their grandchildren. According on the X-linked grandmother hypothesis, the asymmetric inheritance of X-chromosomes should be responsible for the biased effect of the investment by maternal and paternal grandmothers towards granddaughters and grandsons. The British Millennium Cohort Study (n=4445 children) was used to investigate the association between grandmaternal childcare and children's injuries between the ages of 9 months and 3 years. Support was found for the X-linked grandmother hypothesis predicting that the investment of paternal grandmothers benefits more granddaughters than grandsons, the investment of paternal grandmothers benefits granddaughters more than the investment of maternal grandmothers, and the investment of maternal grandmothers is similarly associated with the injuries of granddaughters and grandsons. However, no support was found for the prediction that maternal grandmothers benefit more grandsons than paternal grandmothers. Thus, some, although not univocal, evidence for the prediction that X-chromosomal relatedness shapes the grandmaternal effect on child outcomes was found.
进化理论认为，祖母可以通过投资时间和资源来增加自己的适合度。根据 X 连锁祖母假说，X 染色体的不对称遗传应该负责解释祖母对孙女和孙子投资的偏向效应。本研究使用了英国千禧年队列研究（n=4445 名儿童）的数据，以调查祖母照顾孩子与 9 个月至 3 岁儿童受伤之间的关系。X 连锁祖母假说预测，祖父对孙女的投资比孙子更多，祖父的投资比祖母的投资更有利于孙女，而祖母的投资与孙女和孙子的受伤也有类似的关系。然而，没有证据支持祖母对孙子的投资比对祖父的投资更多的预测。因此，虽然证据并不一致，但发现了一些证据表明 X 染色体的亲缘关系塑造了祖母对儿童结果的影响。
