Absence of gene causes male-male courtship

CHICAGO, May 29 (UPI) -- U.S. medical scientists say the absence of a gene know as sphinx produces increased male-male courtship in the common fruit fly, Drosophila melanogaster.

The University of Chicago Medical Center scientists said high levels of male-male courtship are widespread in many fly species but not in Drosophila melanogaster, which researchers led by Professor Manyuan Long previously discovered possess the sphinx gene, while other fly species don't.

To study the 2 million-year-old gene, graduate students Hongzheng Dai and Ying Chen created flies with a suppressed version of the sphinx gene. Loss of the gene produced no apparent individual changes.

But when the researchers put two males lacking the sphinx gene together, they noticed the males were "interested in other males." They repeated the experiment many times and it consistently produced the same results: Males without sphinx pursued each other more than 10 times longer than did males with a working copy of the gene.

The study that included researchers Sidi Chen, Qiyan Mao, David Kennedy, Patrick Landback and Wei Du, along with Adam Eyre-Walker of Britain's University of Sussex, appears in the Proceedings of the National Academy of Sciences.