Published collaboration of Université de Sherbrooke and Bishop’s
The « grandmother effect » : more children who lived longer
Sherbrooke, le 7 février 2019 – From a biological perspective, menopause in women is puzzling: in comparison to what is observed in other species, it occurs much earlier, long before the end of women’s life expectancy. This led researchers from the Université de Sherbrooke and Bishop’s University to wonder if the relatively early end of reproductive capacity for women might present advantages with regard to gene transmission, by helping their daughters to have larger families.
Their findings, which are published today in the prestigious Current Biology scientific journal, constitute new supporting evidence to the “grandmother hypothesis”
By studying the exceptionally well-detailed demographic data available of the first French settlers in Québec between 1608 and 1799, first author Dr. Sacha Engelhardt – a postdoctoral fellow at the Université de Sherbrooke, whose work was co-supervised by Dr. Fanie Pelletier, Canada Research Chair (CRC) on Evolutionary Demography and Conservation at the Université de Sherbrooke, and Dr. Patrick Bergeron, of Bishop’s University’s Biology Department – found that having a grandmother in proximity to her daughters was statistically associated with more grandchildren being born, and an increased likelihood those grandchildren would reach maturity.
“Research results suggest grandmothers played a critical role in Québec’s preindustrial population,” Dr. Engelhardt explains. “We were very interested on looking at the geographical effect on humans’ life events, such as the age of first reproduction, how many children were born and how many reached the age of 15, for instance.”
“In our study, women whose mothers were alive had more children, and more of those children lived to the age of 15,” explains Dr. Bergeron. “Interestingly, the grandmother effect decreased as the grandmother-daughter geographic distances increased, suggesting that the potential for help may be related to geographic proximity.”
“The results show that daughters with geographically close living mothers on average were able to have two more children, and that the number of children living at the age of 15 increased by about one on average, compared to families where the maternal grandmother had passed away,” Dr. Pelletier explains. “This is a significant evolutionary advantage considering that in parts of that period, sometimes up to about a third of children born did not survive their first year.”
To complete their work, researchers collaborated with Dr. Alain Gagnon and Dr. Lisa Dillon, of the Université de Montréal’s Programme de recherche en démographie historique to access the vast amounts of data used to reach their conclusions. The study also benefited from using the Mammouth supercomputer of the Université de Sherbrooke’s Centre for Scientific Computing to analyze the data.
The research was supported by a postdoctoral fellowship of the Fonds de recherche nature et technologie du Québec (FQRNT), the CRC on Evolutionary Demography and Conservation the Quebec Centre for Biodiversity Science, the Social Sciences and Humanities Research Council (SSHRCC), the Canada Foundation for Innovation (CFI) and the Natural Sciences and Engineering Research Council of Canada (NSERC).
About Bishop’s University
Bishop's University, which was founded in 1843, is a predominantly residential, undergraduate university in Sherbrooke, Quebec. It provides a high quality education in the humanities, natural sciences, social sciences, business, and education. Its small size (2,400 full-time students) allows students to develop close relationships with their professors and each other.
About the Université de Sherbrooke
The Université de Sherbrooke lies at the center of one of Quebec's three major research hubs. Recognized for its sense of innovation, the university is a key partner of senior and regional governments in promoting social, cultural, and economic development. Moreover, the university stands out because of the significant growth in its research activities in recent years, its technology-transfer successes, and its entrepreneurial and open-innovation initiatives in collaboration with industry and social communities.
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Geneviève Lussier, Media Relations Officer
Université de Sherbrooke
819-821-8000, ext. 65472
Olivier Bouffard, director of communications
819 822-9600, ext. 2840