Molecular evidence for soybean domestication

Abstract

Crop domestication is a good example of plant–human co-evolution. Seed gathering and human cultivation of crops were observed since the Neolithic period, as shown by archeological evidence. Numerous studies have been conducted to identify genes related to domestication. With the development of molecular techniques (molecular markers and next-generation sequencing) and bioinformatics, a greater understanding of crop domestication and improvement has been established, including the origins of crops, the numbers of independent domestication events, the molecular diversity of domestication-related traits (DRTs), and the selection pressures. A comparison of the genome sequences between wild species and cultivated crops may provide key information regarding the genetic elements involved in speciation and domestication. Therefore, sequencing projects of currently important crops and their wild relatives are in progress. Accordingly, whole genome sequencing of soybean could provide new knowledge about domestication of this important crop. In this review, we introduce the archaeological evidence of soybean domestication and summarize the DRTs in soybean populations of crosses between cultivated (Glycine max) and wild soybean (G. soja). Soybean domestication is discussed at the sequence level. The current hypothesis of soybean domestication considers that G. max was domesticated from G. soja. However, our previous work suggested that soybean was domesticated from the G. soja/G. max complex that diverged from a common ancestor of these two species of Glycine. This review explores soybean domestication history by focusing on nucleotide diversity using resequencing. Analysis of genes around DRTs at the population level may clarify the domestication history of soybean.