Genome duplications and domestication in common bean

Whole genome duplication (WGD) is a major factor in the evolution of species. This study was designed to investigate the duplication history of legumes. The number of duplication events in each of 10 species is determined using the Ks distribution of paralogs. The duplication events relative to speciation are determined using the relative rate correction, paralog and ortholog Ks peak comparison. All these suggest whole genome duplication before the divergence of legumes. This was further supported by tree reconciliation of gene trees with a species tree. Additional WGD were observed in the lineages leading to Glycine, A. hypogaea and L. albus.;Common bean is an important legume that forms the core of dietery proteins. The wild ancestor was geographically separated into two genepools at about 0.1 Ma with continuous geneflow between the genepools. Domestication is a complex evolutionary process where wildtypes were selected for desired traits that led to well adapted landraces. It is established that there was an independent domestication event in each of the genepools. Our study is designed to estimate the number of domestication events in each genepool. Neighbor joining trees of chalcone isomerase gene suggest a single domestication event in Andean genepool and two domestication events in Middle America genepool. Further approximate bayesian computation approach was used to detect the number of domestication events in each of the genepools using sequences of multiple loci. A single domestication event in each genepool was found with a bottleneck population of 50% effective population size capturing about 85% and 70% of diversity in MA and Andean genepools respectively. Further, the duration of domestication events is estimated to be 1900 and 1500 years for the MA and Andean genepools respectively. Degree of decay of LD increased from wildtypes to landraces suggesting that landraces are appropriate for association mapping.