Genome rearrangements and pervasive meiotic drive cause hybrid infertility in fission yeast.
Bottom Line: Hybrid sterility is one of the earliest postzygotic isolating mechanisms to evolve between two recently diverged species.Two of these driving loci are linked by a chromosomal translocation and thus constitute a novel type of paired meiotic drive complex.Our study reveals how quickly multiple barriers to fertility can arise.
Affiliation: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States.Show MeSH
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Mentions: Given the observed reciprocal incompatibility between Sk and Sp chromosomes 2 and 3 due to the translocation, we reasoned that the observed drive phenotypes of Sk alleles on these chromosomes could be interdependent. This scenario is easiest to understand in the rec12Δ crosses, which are not complicated by recombination. For example, if allele(s) on K2 drive, K3 may appear to drive just because spores that inherit K2 and P3 are inviable. The converse could also be true. This line of thinking inspired us to test whether each Sk chromosome can drive independently, in the absence of drive on the other two chromosomes. We used rec12Δ strains to eliminate recombination-associated phenotypes. To test for the ability of K1 to drive autonomously, we crossed a P1 K2 K3 strain (obtained from a rec12Δ hybrid cross) to a naïve K1 K2 K3 strain to generate a P1 K2 K3/K1 K2 K3 diploid. We found that even in these diploids, which were heterozygous for only chromosome 1, the K1 chromosome showed the drive phenotype (G-test p<0.01 Figure 8A, Figure 8—figure supplement 1), proving that the driving allele on K1 can act even in the absence of K2 and K3 drive.10.7554/eLife.02630.030Figure 8.Sk drive alleles are autonomous and contribute to hybrid infertility.
Affiliation: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States.