Evolution of a Young Social Supergene in Fire Ants
Talk at College de France Supergene symposium
In Paris, Tatiana Giraud and her team including Jay Paul and Ricardo Rodriguez de la Vega organised a superb symposium on the evolution supergenes and sex chromosomes. The speaker lineup was superb, the food was great and the discussions were extremely stimulating. Yannick also had the honor of presenting our recent work on the fire ant social supergenes, highlighting that:
the Sb supergene responsible for multiple-queen colonies evolved in one species and repeatedly introgressed into other species. Thus the benefits of the new social form are sufficient to outweigh the genetic incompatibilities of carrying a large piece of chromosome from another species.
the young Sb supergene for which recombination is suppressed is accumulating deleterious mutations, including new transposable elements and expansions of existing repetitive elements. These have led the Sb supergene to almost double in size compared to SB. This degenerative expansion is an early stage of supergene evolution, that likely occurs in many other systems but is difficult to detect in them.
when comparing gene expression in the fire ant supergene system, most highly significant differences in gene expression are due to the genetic architecture of the system, and gene-by-gene dosage compensation for the degeneration of Sb, and only few patterns have the signature of socially antagonistic selection ELIFE paper.
June 10, 2022