Lifespan of fruit flies is primarily inherited within the sexes

These can affect disease risk and are in general believed to have the same effect on males and females. A new study on fruit flies, by researchers based in Germany and Sweden, overthrows this view and demonstrates that genetic factors commonly have radically different effects on lifespan in the two sexes.

To reach this conclusion, the scientists used sophisticated genetic techniques to clone genotypes and express them in both male and female flies. This allowed them to investigate the sex-specificity of genes on lifespan. On average females outlived males, but the relative effect of a genotype was surprisingly inconsistent between the sexes. The results were recently published in the scientific journal the American Naturalist, and the study has been conducted by researchers at Uppsala University, Sweden, and Bielefeld University, Germany.

While some genotypes gave females a relatively long lifespan they had the opposite effect on males – and vice versa. The sex-specificity of genetic effects substantially reduced the heritability of lifespan between parent and offspring of opposite sex, so that the mother-to-son and father-to-daughter heritabilities were less than half of those between parent and offspring of the same sex.

“A consequence of our findings is that if fruit flies were interested to predict their lifespan based on that of relatives, they should put more trust in ancestors of their own sex than those of the opposite sex. The results from this study also indicate that disease genetics differs vastly between the sexes”, says one of the coauthors, Urban Friberg.

Read the article in the American Naturalist.