ALBERT

Description: Fusarium verticillioides is an agriculturally important fungus because of its association with maize and its propensity to contaminate grain with toxic compounds. Some isolates of the fungus harbor a meiotic drive element known as Spore killer ( Sk K ) that causes nearly all surviving meiotic progeny from an Sk K x Spore killer -susceptible ( Sk S ) cross to inherit the Sk K allele. Sk K has been mapped to chromosome V but the genetic element responsible for meiotic drive has yet to be identified. In this study, we used cleaved amplified polymorphic sequence markers to genotype individual progeny from an Sk K x Sk S mapping population. We also sequenced the genomes of three progeny from the mapping population to determine their single nucleotide polymorphisms. These techniques allowed us to refine the location of Sk K to a contiguous 102 kb interval of chromosome V, herein referred to as the Sk region. Relative to Sk S genotypes, Sk K genotypes have one extra gene within this region for a total of 42 genes. The additional gene in Sk K genotypes, herein named SKC1 for Spore Killer Candidate 1 , is the most highly expressed gene from the Sk region during early stages of sexual development. The Sk region also has three hyper-variable regions, the longest of which includes SKC1 . The possibility that SKC1 , or another gene from the Sk region, is an essential component of meiotic drive and spore killing is discussed.