The genetics of a putative social trait in natural populations of yeast.
Bottom Line: Here we find that 110 wild yeast strains isolated from natural habitats, and all contained a single SUC locus and produced invertase; none were 'cheats'.The only genetic variants we found were three strains isolated instead from sucrose-rich nectar, which produced higher levels of invertase from three additional SUC loci at their subtelomeres.We argue that the pattern of SUC gene variation is better explained by local adaptation than by social conflict.
Affiliation: Max Planck Institute for Evolutionary Biology, August Thienemann Strasse 2, Plön, 24306, Germany.Show MeSH
Mentions: Our Southern blots showed that all the wild S. paradoxus strains isolated from oak and maple trees contained just a single SUC locus, SUC2, located on chromosome IX. All 27 S. cerevisiae strains isolated from nature also contained SUC2 on chromosome IX, but three S. cerevisiae strains (C.Nectar.1, C.Nectar.2 and C.Nectar.3) contained additional SUC loci on chromosome II (SUC3), on chromosome X (SUC8) and on chromosome XIV (SUC9) (Figs S1 and S2, Supporting information). ddPCR (Fig.2) shows that the SUC copy number of the three wild strains with multiple loci is closest to four, corresponding to one SUC open reading frame for each chromosome with a SUC locus (SUC2, plus the extra loci SUC3, SUC8 and SUC9). All three of these wild strains were isolated from the same environment: Bertam palm (Eugeissona tristis) nectars in West Malaysia (Liti et al. 2009).
Affiliation: Max Planck Institute for Evolutionary Biology, August Thienemann Strasse 2, Plön, 24306, Germany.