In This Issue

Sex-determination mechanism in ants, bees, and waspsAnimals have evolved numerous unique sex-determination mechanisms, which evolve over time.In the insect order Hymenoptera, which includes ants, bees, and wasps, female sex is usually determined when an egg carries two different versions of a particular gene.For ants, the sex-determining gene is ANTSR.To better understand the evolutionary origins of ANTSR and its conservation throughout Hymenoptera, Chuanxin Yu et al. analyzed 41 Hymenoptera genomes.The authors found that the region surrounding ANTSR has been conserved through 200 million years of evolution.In bumblebees and hornets, as in ants, only females carry two different versions of ANTSR, confirming the region's role in sex determination.The authors found no similarities in the ANTSR DNA sequence among ants, bees, and hornets but found that for all three insect types, the gene resides in the same region of the genome.The findings suggest that this region has conserved its function of sex determination through its position within the genome rather than its sequence, highlighting an unusual mechanism of sex locus evolution.According to the authors, Hymenopteran insects could represent a useful model for the evolution of sex determination beyond the well-studied mechanism involving sex chromosomes.-A.K.