In common with other higher life forms, the readers of Science are diploids, carrying one set of chromosomes from their mother and a second set from their father. Yet many eukaryotes exist quite happily in the haploid state, with only one set of chromosomes and thus only one set of genes. This observation prompts the question: Is there any particular evolutionary advantage to being diploid? On page 555 of this issue, Zeyl et al. (1) turn this question on its head and instead ask whether haploidy carries an evolutionary advantage. In their experiments, they exploit a valuable eukaryote, the budding yeast Saccharomyces cerevisiae, which grows and reproduces in both the haploid and diploid states.
展开▼
