Researchers have discovered the genetic basis for a quirk of the animal kingdom — how ant queens produce broods that are entirely male or female.

«It’s weird to have any parent that’s only producing one sex or the other,» said UC Riverside entomologist and study author Jessica Purcell.

Scientists have known for some time that ant colonies can specialize in producing all-male or all-female offspring. For the first time, UC Riverside scientists have located a set of genes on a single chromosome that are associated with this phenomenon.

Their discovery is described in a new article published by the Proceedings of the National Academy of Sciences.

When humans mate, both parents contribute one copy of the genome to their offspring. However, female ants are the only ones that carry two copies, like humans and most other animals do, while the males carry only one copy.

«Male ants develop from unfertilized eggs their mother lays,» said UCR evolutionary biologist and senior study author Alan Brelsford. «Therefore, male ants, as well as bees and wasps, genetically have a mother but no father.»

Purcell and Brelsford found their study specimens in 2016 while on a journey to collect and study ants from Riverside all the way to the Arctic Circle. In northern Canada’s Yukon territory, they found more than 100 colonies of two Formica ant species that appeared ready for their annual reproductive flights. Back in Riverside, ecology doctoral student German Lagunas-Robles analyzed the genomes of these ants, looking for differences between male-producing and female-producing colonies.

Story Source:
Materials provided by University of California — Riverside. Original written by Jules Bernstein. Note: Content may be edited for style and length.