Linkage disequilibrium and sequence diversity in a 500-kbp region around the adh1 locus in elite maize germplasm.

Linkage disequilibrium (LD) at the adh locus was examined in two sets of maize inbreds. A set of 32 was chosen to represent most of the genetic diversity in the cultivated North American elite maize breeding pool. A second set of 192 inbreds was chosen to sample more deeply the two major heterotic groups in elite maize germplasm. Analysis of several loci in the vicinity of the adh gene shows that LD as measured by D' and r2 extends greater than 500 kbp in this germplasm. The presence of this exceptionally long segment of high LD may be suggestive of selection acting on one of the genes in the vicinity of adh1 or of a locally reduced rate of recombination.