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: One explanation for a chromosome rearrangement-independent mechanism of hybrid infertility emerged from our studies following the transmission of alleles from each species' chromosome through meiosis in Sk/Sp hybrids. To focus on cells with only one copy of a given allele, we omitted heterozygous diploids from analyses of all alleles and omitted heterozygous aneuploids when analyzing transmission of alleles on chromosome 3. Surprisingly, we found that in all cases, the Sk allele was transmitted to more viable spores than the Sp allele (Figure 6A,B, Figure 6—figure supplement 1). This phenotype was not specific to the markers used, or which species contributed the marked (mutant) allele to the Sk/Sp hybrid diploid. In addition, the overrepresentation of Sk alleles from chromosomes 1 and 2 in the viable spores was observed within both haploid and aneuploid spores (Figure 6—figure supplement 2). This suggests the enhanced transmission of Sk alleles on these chromosomes is independent of the aneuploidy phenotype.10.7554/eLife.02630.024Figure 6.Alleles on all three Sk chromosomes show drive (independent of mitochondrial DNA type).
Affiliation: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, United States.