A UT Arlington research team says their study of genetic information from more than 4,000 beetle species has yielded a new theory about why some species lose their Y chromosome and others, such as humans, hang on to it.
They call it the "fragile Y hypothesis."
The biologists' idea is that the fate of the Y chromosome is heavily influenced by how meiosis, or the production of sperm, works in an organism. They believe the size of an area where X and Y genetic information mingle or recombine can serve as a strong clue that a species is at risk of losing the Y chromosome during sperm production. Previous work has attributed Y chromosome loss to the lesser importance of genes it carries.
Heath Blackmon, a Ph.D. student at The University of Texas at Arlington, said most previous research into sex chromosomes has occurred either in mammals or the fruit fly. But, beetles are the most diverse group on the planet scientists have already described and given names to over 350,000 species.
"One of the big reasons that we wanted to do this study was to see if beetles would reveal anything new about the way that sex chromosomes evolve," said Blackmon, who also worked on the research at the National Evolutionary Synthesis Center in Durham, North Carolina.
Blackmon and Jeffery Demuth, UT Arlington associate professor of biology, co-authored a paper published in the June issue of Genetics on the work, which is supported by a grant from the National Institutes of Health. The paper is a part of a special "Genetics of Sex" collection from the Genetics Society of America.
The X and Y genes control human sex determination, with an XY combination resulting in a male and an XX combination resulting in a female. Researchers study the evolution of these chromosomes, in part, to learn more about human evolution and disease. Some diseases, such as hemophilia, are associated only with genes on the sex chromosomes.
Like humans, sex determinat
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University of Texas at Arlington