MISSISSAUGA, Ontario, June 4 (UPI) -- Sex genes that were predicted to reside on the sex chromosomes actually are located throughout the genome, a Canadian researcher found.
Mark Fitzpatrick, a researcher at the University of Toronto, reported that genes for male sexual traits and female mating preferences are not preferentially located on the sex chromosomes because they often influence multiple traits, such as fertility, development, vision and life span -- roles that affect their location.
Fitzpatrick studied the fruit fly genome database for sexually selected genes and found of the 63 sex genes, about 75 percent had multiple functions, about the same percent as 100 random genes he studied.
These multiple roles suggest evolution and the spread of favorable sex genes are limited by factors unrelated to sex.
"Each gene may experience an internal tug of war," Fitzpatrick said. "Changes in a gene that result in a brighter and bushier tail may cause defects in heart function."
Sex linkage theories are not necessarily incorrect, he said, but added researchers now can see there are more complex relationships.
