Fig. 6

Geographic distribution of GIa haplotypes in soybeans. a Distribution of the GsGIa haplotypes of wild soybeans. 47 haplotypes were named as H1 to H47. b Distribution of the GmGIa haplotypes in soybean landraces. Three haplotypes were designated as H1, H2, and H3, which are shared by the wild soybeans. The haplotypes of domesticated soybeans in Japan are also restricted to H1 to H3 for 20, 7, and 5 individuals respectively [35]. Gm, G. max; Gs, G. soja. The colored symbols represent the different GIa haplotypes as indicated. c The GmGIa radiation pathways during soybean domestication. In wild populations, H1, H2, and H3 were restricted to different ecological regions in China: H1 in the Yellow River region (pink and green), H2 in NR (gray), and H3 in NER (yellow). Three major radiation events and places of GmGIa H1 (red), H2 (green), and H3 (blue) are proposed by different color arrows. H3 is assumed to be later introgressed from the wild soybeans in Northeast region of China, thus the very likely origin place of the domesticated soybeans might be the Yellow River region and the SR of China. However, considering the H1 distribution in wild soybeans, and the dominant H1 frequency in cultivated soybeans, the major domestication event might occur in the Yellow River region of China. The yellow, green, red, and gray areas respectively indicate NER, NR, HR and SR ecological regions in China. The blue line represents the Yellow River. The pink star indicates Beijing. Latitudinal and longitudinal coordinates are shown. The baseline map was created by us using DIVA-GIS version 7.5.0