in male and female fruit flies whose mitochondria came from different origins. They found genetic variations in both male and female mitochondrial DNA, but only the male ones could be linked to life expectancy. There weren't just a few mutations in one place, there were several, spread all over the mitochondrial genome. The researchers suggest the mutations are entirely due to the way mitochondrial DNA is passed down through the female line. Dowling said combining this latest study with their earlier work suggests mitochondria are "hotspots" for mutations that influence male health.
Thursday, December 6, 2012
Genetic clue discovered for why women outlive men
A new study of mitochondrial DNA in fruit flies offers a number of clues that might explain why females tend to outlive males across much of the animal kingdom, including humans. They found male fruit flies appear to have mutations in their mitochondrial DNA that affect how fast they age and how long they live. Senior author Damian Dowling, a research fellow in the Monash School of Biological Sciences, told the press, "All animals possess mitochondria, and the tendency for females to outlive males is common to many different species. Our results therefore suggest that the mitochondrial mutations we have uncovered will generally cause faster male aging across the animal kingdom. Intriguingly, these same mutations have no effects on patterns of aging in females. They only affect males." Thus, as mitochondrial DNA is passed down from generation to generation, the process of natural selection has no opportunity to "screen out" mutations in mitochondrial DNA that might be harmful to males. The researchers refer to this as a "sex-specific selective sieve". For their study, Dowling and colleagues looked at differences in longevity and biological aging
in male and female fruit flies whose mitochondria came from different origins. They found genetic variations in both male and female mitochondrial DNA, but only the male ones could be linked to life expectancy. There weren't just a few mutations in one place, there were several, spread all over the mitochondrial genome. The researchers suggest the mutations are entirely due to the way mitochondrial DNA is passed down through the female line. Dowling said combining this latest study with their earlier work suggests mitochondria are "hotspots" for mutations that influence male health.
in male and female fruit flies whose mitochondria came from different origins. They found genetic variations in both male and female mitochondrial DNA, but only the male ones could be linked to life expectancy. There weren't just a few mutations in one place, there were several, spread all over the mitochondrial genome. The researchers suggest the mutations are entirely due to the way mitochondrial DNA is passed down through the female line. Dowling said combining this latest study with their earlier work suggests mitochondria are "hotspots" for mutations that influence male health.
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I'm wondering if this could be possible because the mitochondrial DNA comes specifically from the mother. Since it is female DNA, perhaps it functions at its best with female offspring? On the other hand, since the mitochondrial DNA is undeniably maternal, could the change to a male offspring be the jolt that causes so many mutations within the mitochondrial genome. I believe this question could be answered if scientists were to actually look at the mitochondrial DNA of male individuals throughout different spans of life. This could help determine at what point the genome begins to mutate in males.
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