Fig 3.

Long-range loss of heterozygosity in hybrids between syntenic parental genomes, with a possible mechanism. Figures were constructed for the three best-characterized natural hybrids: S. pastorianus Weihenstephan (142), S. cerevisiae-S. kudriavzevii W27 (12), and M. sorbitophila (105). Homologous pairs (or triplets) are shown as colored bars and designated by letters, following chromosome numbering. Ovals symbolize centromeres. (A) Examples of LOH extending to chromosome ends. (B) Examples of chimeric chromosomes. (C) Hypothetical mechanism to explain the formation of both LOH and chimeric chromosomes during the successive mitotic divisions of hybrids. A first BIR event produces a long-range LOH segment extending to the telomere, as shown in panel A. A second, identical BIR event during a subsequent mitosis creates chimeric chromosomes, as shown in panel B. (Top row adapted from reference 142 by permission of Oxford University Press.)