New research published in April 2019 identifies the genomic features that might have made domestication possible for corn and soybeans, two of the world's most critical crop species. The research, published in the peer-reviewed academic journal Genome Biology, has implications for how scientists understand domestication, or the process by which humans have been able to breed plants for desirable traits through centuries of cultivation. The researchers drew on vast amounts of data on the genomes of corn and soybeans and compared particular sections of the genomes of wild species and domestic varieties, noting where the genomes diverged most markedly. Iowa State University researchers worked with scientists from the University of Georgia, Cornell University and the University of Minnesota. The researchers studied more than 100 accessions from comparisons of corn with teosinte, its progenitor species. They also looked at 302 accessions from a dataset of wild and domesticated soybeans. "We sliced the genomes into specific sections and compared them," said Jianming Yu, professor of agronomy and Pioneer Distinguished Chair in Maize Breeding. "It's a fresh angle not many have looked at concerning genome evolution and domestication. We searched for 'macro-changes,' or major genome-wide patterns -- and we found them." Human cultivation created a bottleneck in the genetic material associated with corn and soybeans, Yu said. As humans selected for particular traits they found desirable in their crops, they limited the genetic variation available in the plant's genome. However, the researchers found several areas in the genomes of the species involved in the study where genome divergence seemed to concentrate. "These patterns in genome-wide base changes offer insight into how domestication affects the genetics of species," said Jinyu Wang, the first author of the paper and a graduate student in agronomy. (Source: Agriculture and Food News, ScienceDaily.
Photo Credit: Sherry Flint-Garcia (teosinte) and Scott Jackson (Glycine soja)
Left: highly branched plants of teosinte, a wild relative of corn. Right: tiny pods on the vine of Glycine soja, wild relative of soybean. New research sheds light on how domestication affects the genomes of corn and soybeans.