Researchers at Lund University in Sweden have investigated how the X and Y chromosomes evolve and adapt to each other within a population. The results show that breaking up coevolved sets of sex chromosomes could lead to lower survival rates among the offspring - something that could be of importance in species conservation, for example. The study is published in the journal PNAS .
The results provide new clues on how species are formed, and suggest it could be harmful to bring together individuals from different populations that have been separated for a long time. The reason is that the offspring have lower survival rates.
"This is something worth keeping in mind in conservation biology, where you want to see a population grow", says Jessica Abbott, researcher in evolutionary ecology at Lund University.
It is previously known that hybrids between different species often do better if they are female (two X chromosomes) rather than male (X and Y chromosome).
In the study, the researchers crossed fruit flies from five different populations from different continents in order to combine X and Y chromosomes with different origins. They then followed and studied the subsequent generations.
The results show that males with X and Y chromosomes that don't match had higher reproductive success than males with matching X and Y chromosomes. However, the higher male fertility was paired with lower survival rates among their offspring.
"We were expecting the opposite, that males with different origin X and Y chromosomes would have lower reproductive success, so that was surprising", says Jessica Abbott.
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Proceedings of the National Academy of Sciences