New research released this week identifies the genomic traits that could have made possible the domestication of corn and soybeans, two of the world's most critical crop species.
Research Genome Biology published Thursday in the peer-reviewed academic journal, has implications for how scientists understand domestication or how humans could breed plants for desirable traits through centuries of cultivation. Using huge amounts of data on the genomes of corn and soybeans, researchers compared specific sections of the genomes of wild species and native varieties and determined where the genomes diverged most.
Researchers from the University of Iowa State University worked with scientists from the University of Georgia, Cornell University, and the University of Minnesota. The researchers examined more than 100 accessions from comparisons of corn with the precursor Teosinte. They also looked at 302 hits from a data set of wild and domesticated soybeans.
"We have divided the genomes into sections and compared them," said Jianming Yu, professor of agricultural science and Pioneer Distinguished Chair in Maize Breeding. "This is a new perspective that not many have considered in terms of genome evolution and domestication, and we looked for" macro-changes "or genome-wide patterns – and found them."
Human cultivation led to a bottleneck in genetic material associated with corn and soybeans, Yu said. Since humans were selected according to specific traits that they considered desirable for their plants, they limited the genetic variation that is available in the genome of the plant. However, the researchers found several areas in the genomes of the species involved in the study where genome divergence seemed to focus.
"These patterns in genome-wide baseline changes shed light on how domestication affects the genetics of the species," said Jinyu Wang, the newspaper's first author and a graduate student in agronomy.
The variation of nucleotide bases between wild and domesticated species appeared in non-genetic parts of genomes or in parts that do not encode more proteins. The study also found greater variation in pericentromeric regions or in areas near the centromere of chromosomes and in areas of high methylation or in areas where methyl groups are added to a DNA molecule. Methylation can alter the activity of a DNA segment without altering its sequence.
The study investigated the occurrence of mutations in the genomes of domesticated crops and their precursor species.
"We now believe that they are good candidates Domestication, such as corn and soybeans, take a middle ground in their willingness to mutate," said Xianran Li, associate professor of agronomy and co-author of the study.
"If there is no mutation, everything stays the same and we have no evolution," said Yu. "But too many mutations can extinguish a species."
The results of the study pointed to important connections between the UV radiation of the sun and the evolution of the genome. UV radiation is a natural mutagen, leaving a unique footprint as it forms, Yu said. The authors of the study found much more of these footprints in modern corn and soybeans than their wild relatives.
Corn genetics provide insight into the historical distribution of cultivated plants throughout America
Research highlights the genomic traits that make plants good candidates for domestication (2019, April 24)
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