SoyMap2: Investigating Genetic Diversity in Wild Relatives of Soybean

Domestication and cultivar selection have reduced the genetic diversity within soybean. Loss of genetic diversity can result in susceptibility to emerging diseases or pests and could limit future genetic gains. A key goal of the NSF funded SoyMap2 project is to develop resources that can assist in crop improvement, by determining the diversity within a set of wild perennial Glycine species. The seven Glycine species used in this study are native to Australia, and grow in diverse geographical areas and climate conditions. The SoyMap2 group is evaluating genic diversity by generating genome-guided transcriptome assemblies for each of the seven wild perennial Glycine species. Reference transcritpome assembly results to date show that we have captured approximately 50% of the coding sequences present in Glycine max (assembly version 2). The SoyMap2 group is evaluating genomic diversity by sequencing twelve ~half-megabase genomic regions selected to include many traits with potential utility for soybean improvement. The twelve regions consist of six pairs derived from the Glycine whole genome duplication. BAC sequencing results to date show that the Glycine species have approximately 85% sequence similarity to the soybean genome assembly within coding regions, but have generally diverged radically outside of coding regions. Comparisons of paired BAC-end data also show regions of relative expansion and contraction among the Glycine species, since divergence from a common ancestor ~5 Mya.