Figure 4 - available via license: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Content may be subject to copyright.
(A) The Sma/Smd genotype in F. glacialis occurs in approximately half of workers from 650
Source publication
Sexually reproducing organisms usually invest equally in male and female offspring. Deviations from this pattern have led researchers to new discoveries in the study of parent-offspring conflict, genomic conflict, and cooperation. Some social insect species exhibit the unusual population-level pattern of split sex ratio, wherein some colonies speci...
Contexts in source publication
Context 1
... developed two PCR-RFLP assays to distinguish these three genotypes in a and Sma/Sma homozygotes, while workers from male-producing colonies are most 204 often Sma/Sma homozygotes or Sp/Sma heterozygotes (Fig. 4a). This suggests that 205 . CC-BY-NC-ND 4.0 International license available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is ...
Context 2
... copyright holder for this preprint this version posted January 25, 2021. ; https://doi.org/10. 1101/2021 gyne-producing monogyne colonies are usually headed by Sma/Smd queens, while 206 male producing monogyne colonies are usually headed by Sma/Sma queens (Fig. ...
Context 3
... at each colony, we show that 31 out of 34 gyne-producing colonies harbor at 208 least one Sma/Smd worker out of eight genotyped, while 27 out of 34 male-producing 209 colonies harbor only Sma/Sma workers and Sma males (Fig. 4c). Among the remaining 210 male-producing colonies, three harbor only Sp/Sma workers (and are likely ...
Context 4
... males invariably carry the same allele at two out of 12 microsatellite loci, while 299 females are almost always heterozygous at these loci (20). Diploid eggs that were 300 homozygous for the male-associated alleles at these loci failed to develop. In F. (Fig. 4). Polygyne colonies harbored almost CC-BY-NC-ND 4.0 International license available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is ...
Citations
Significance
Some social insects exhibit split sex ratios, wherein a subset of colonies produce future queens and others produce males. This phenomenon spawned many influential theoretical studies and empirical tests, both of which have advanced our understanding of parent–offspring conflicts and the maintenance of cooperative breeding. However, previous studies assumed that split sex ratio was not under genetic control. Here, we show that split sex ratio is associated with a large genomic region in two ant species. The discovery that sex allocation can have a genetic basis provides an additional perspective on this well-studied trait of social insects.
Supergenes, regions of the genome with suppressed recombination between sets of functional mutations, contribute to the evolution of complex phenotypes in diverse systems. Excluding sex chromosomes, most supergenes discovered so far appear to be young, being found in one species or a few closely related species. Here, we investigate how a chromosome harboring an ancient supergene has evolved over about 30 Ma. The Formica supergene underlies variation in colony queen number in at least five species. We expand previous analyses of sequence divergence on this chromosome to encompass about 90 species spanning the Formica phylogeny. Within the non‐recombining region, the gene knockout contains 22 single nucleotide polymorphisms (SNPs) that are consistently differentiated between two alternative supergene haplotypes in divergent European Formica species, and we show that these same SNPs are present in most Formica clades. In these clades, including an early diverging Nearctic Formica clade, individuals with alternative genotypes at knockout also have higher differentiation in other portions of this chromosome. We identify hotspots of SNPs along this chromosome that are present in multiple Formica clades to detect genes that may have contributed to the emergence and maintenance of the genetic polymorphism. Finally, we infer three gene duplications on one haplotype, based on apparent heterozygosity within these genes in the genomes of haploid males. This study strengthens the evidence that this supergene originated early in the evolution of Formica and that just a few loci in this large region of suppressed recombination retain strongly differentiated alleles across contemporary Formica lineages.
