RT Journal Article SR Electronic T1 Evolution of the mating type locus with suppressed recombination JF bioRxiv FD Cold Spring Harbor Laboratory SP 518654 DO 10.1101/518654 A1 Zena Hadjivasiliou A1 Andrew Pomiankowski YR 2019 UL http://biorxiv.org/content/early/2019/01/11/518654.abstract AB The two partners required for sexual reproduction are rarely the same. This pattern extends to species which lack sexual dimorphism yet possess self incompatible gametes determined at mating type regions of suppressed recombination, likely precursors of sex chromosomes. In this work we investigate the role of cellular signaling in the evolution of mating types. We develop a model of ligand and receptor dynamics in individual cells, and identify key factors that determine the capacity of cells to send and receive signals. The model identifies the conditions that lead to the evolution of gametes that produce ligand and receptor in an asymmetric manner and shows how these are affected by recombination. Given that the recombination rate can evolve, the same conditions that favor asymmetric signaling also favor tight linkage of ligand and receptor loci in distinct linkage groups. These results suggest that selection for asymmetric signaling between gametes was the first step in the evolution of non-recombinant mating type loci, paving the road for the evolution of anisogamy and sexes.