SPECIATION

Putting the genetic breaks on breeding

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Science  18 Jul 2014:
Vol. 345, Issue 6194, pp. 281
DOI: 10.1126/science.345.6194.281-a
Mules: An example of hybrid sterility in actionPHOTO: © IMAGEBROKER/ALAMY

Several genetic barriers prevent species from interbreeding. For instance, when two different species mate, their offspring are often infertile. Identifying the genetic causes of this hybrid sterility provides insight into how species evolve genetically. Zanders et al. examined two closely related yeast species, which share 99.5% of their DNA sequence. They found that crosses between the species could not produce fertile offspring because of meiotic drive loci, genetic elements that are preferentially transmitted to the offspring within a species. The three DNA sites, which were present in one of the species, blocked the hybrid from developing spores that contained chromosomes from the other species. This study highlights how quickly barriers to fertility can arise between two closely related species.

eLife 10.7554/eLife.02630.001 (2014).

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