Many of us have heard that women live longer than men, and typically this is true in humans as well as a number of other mammal species, but why? Some theories have posited that males partake in riskier behaviors that limit their life span; others suggest females of some species have better support networks which help them live longer, but now there is a new theory.
A team of researchers from the University of New South Wales believe it is the sex chromosomes that make the difference. Specifically, they hypothesize that having a matching pair of sex chromosomes is the key factor. In humans and other mammals females have matching sex chromosomes (two X chromosomes) which means they are ‘homogametic’, males however have mismatched sex chromosomes (one X and one Y) which means they are ‘heterogametic’. In other species, including birds this is the other way around.
The study investigated 229 different species of animals indicated that homogametic individuals have a longer lifespan, on average 17.6% longer than heterogametic individuals. However, this difference is not equal across all species. In species where females having the matching chromosomes, they live 20.9% longer, but in species where the males are homogametic, they only live 7.1% longer. The team now plans to expand their research to better understand the mechanisms behind these differences in longevity.
Source: Medical News Today
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