One possible explanation for this, according to Beye, is that the two different gene varieties form proteins that combine and are able to turn on other genes that control female development.
Boon for Breeding
Breeding experiments had shown that a sex determination gene must exist in ants, bees, and wasps. But no one had found it until now, commented honeybee geneticist Jay Evans of the United States Department of Agriculture Bee Research Lab in Beltsville, Maryland.
"It is certainly an important find for bees and for insect sex determination generally," he said. "[However,] establishing the rest of the pathway will take substantial work in bees, since it looks to be distinct from known mechanisms."
The finding could also be important for bee breeding initiatives, said Beye. Breeding bees for useful traits, such as low aggression or improved immunity, requires the sequential mating of closely related animals. This can lead to fertilized eggs having both copies of the same CSD gene, creating sterile physiological males.
In the most extreme cases, 50 percent of eggs produce sterile males, which are killed by workers. This fatally depletes the workforce and often means that the hive fails to make it through the winter. The discovery of the CSD gene means that breeders may be able to genetically test bee lines before mating to ensure that fertilized eggs will end up with two different types of the CSD gene.
"We've known for some time that inbred queens do poorly and often produce morphological males," said Evans. "Knowing the actual [gene] will allow for smarter matings by bee breeders that avoid inbreeding costs," he said.
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