Wednesday, January 26, 2022

Why older women are less healthy than older men?

Scientists have long wondered why older women are less healthy than older men, given that men at any given age are more likely to die than women.

According to a new study, genes that act late in life could clarify why women have poorer health than men in more seasoned age. This is due to intralocus sexual conflict- genes that benefit one sex but harm the other.

For the study, scientists used mathematical models and experimental data on flies to show that such genes can quickly spread if they take effect after female reproduction stops.

Professor David Hosken of the University of Exeter said, “Shared genes tether the sexes together in an evolutionary tug of war. Selection is trying to push females and males in different directions, but the shared genome means each sex stops the other from reaching its optimal.”

“Basically, certain genes will make a good male but a bad female, and vice versa. However, after females reach menopause, they no longer reproduce to pass on their genes which means selection (which is a reproduction) on females is greatly weakened.”

“So after that point, any genes that improve late-life male fitness will accumulate, even if they harm female fitness.”

Professor Hosken said, “It was important to note that survival and health are not the same things – and that the accumulation of late-life male benefit genes hinged upon males’ ability to continue reproducing after the age of female menopause.”

Journal Reference
  1. Archer, C.R., Recker, M., Duffy, E. et al. Intralocus sexual conflict can resolve the male-female health-survival paradox. Nat Commun 9, 5048 (2018). DOI: 10.1038/s41467-018-07541-y

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