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Mutants defective in meiotic recombination and synaptonemal complex formation undergo checkpoint-mediated arrest in mid-meiotic prophase. In S. cerevisiae, this checkpoint requires Swe1, which phosphorylates and inactivates the cyclin-dependent kinase Cdc28. A swe1 deletion allows mutants that normally arrest in meiotic prophase to sporulate at wild-type(More)
The hop2 mutant of S. cerevisiae displays a novel phenotype: meiotic chromosomes form nearly wild-type amounts of synaptonemal complex, but most chromosomes are engaged in synapsis with nonhomologous partners. The meiosis-specific Hop2 protein localizes to chromosomes prior to and during synapsis and in the absence of the double-strand breaks that initiate(More)
Hybrids between species are usually unviable or sterile. One possible mechanism causing reproductive isolation is incompatibility between genes from different species. These "speciation" genes are interacting components that cannot function properly when mixed with alleles from other species. To test whether such genes exist in two closely related yeast(More)
The genome-sequencing gold rush has facilitated the use of comparative genomics to uncover patterns of genome evolution, although their causal mechanisms remain elusive. One such trend, ubiquitous to prokarya and eukarya, is the association of insertion/deletion mutations (indels) with increases in the nucleotide substitution rate extending over hundreds of(More)
Mutation is the source of both beneficial adaptive variation and deleterious genetic load, fueling the opposing selective forces than shape mutation rate evolution. This dichotomy is well illustrated by the evolution of the mutator phenotype, a genome-wide 10- to 100-fold increase in mutation rate. This phenotype has often been observed in clonally(More)
Assortative mating, when individuals of similar phenotypes mate, likely plays a key role in preventing gene flow during speciation. Reinforcement occurs when two previously geographically separated (allopatric) groups meet after having evolved partial postzygotic isolation; they are selected to evolve or enhance assortative mating to prevent costly(More)
Nuclear-mitochondrial conflict (cytonuclear incompatibility) is a specific form of Dobzhansky-Muller incompatibility previously shown to cause reproductive isolation in two yeast species. Here, we identified two new incompatible genes, MRS1 and AIM22, through a systematic study of F2 hybrid sterility caused by cytonuclear incompatibility in three closely(More)
Understanding the genetic basis of evolutionary adaptation is limited by our ability to efficiently identify the genomic locations of adaptive mutations. Here we describe a method that can quickly and precisely map the genetic basis of naturally and experimentally evolved complex traits using linkage analysis. A yeast strain that expresses the evolved trait(More)
One of many physiological adjustments in quiescent cells is spatial regulation of specific proteins and RNA important for the entry to or exit from the stationary phase. By examining the localization of epigenetic-related proteins in Saccharomyces cerevisiae, we observed the formation of a reversible cytosolic "stationary-phase granule" (SPG) by Hos2, a(More)
The Saccharomyces cerevisiae HOP2 gene is required to prevent formation of synaptonemal complex between nonhomologous chromosomes during meiosis. The HOP2 gene is expressed specifically in meiotic cells, with the transcript reaching maximum abundance early in meiotic prophase. The HOP2 coding region is interrupted by an intron located near the 5' end of the(More)