University of Nebraska–Lincoln scientist James Schnable and international colleagues have created the first complete map of the corn genome, a landmark achievement that can enable major long-term advances in crop health, resilience and productivity.
“These research findings can help us build tools to predict which new corn varieties will perform well in particular environments, because we will be better able to identify the functions of individual genes in corn,” said Schnable, Charles O. Gardner Professor of Agronomy.
Schnable and scientists from Iowa State University and China recently published their findings, titled “A Complete Telomere-to-Telomere Assembly of the Maize Genome,” in the journal Nature Genetics. Their findings come one year after the complete mapping of the human genome.
Scientists have devoted much effort this century to identifying the full breadth of the corn genome, the set of genetic material that plays a critical role in determining a corn plant’s physical characteristics, growth and health. Mapping the full breadth of corn’s genetic material has been a longtime challenge because the corn genome is large and immensely complex.
Technology used in the first draft of a corn genome, in 2009, identified a significant portion of corn’s wide variety of genetic material. Still, many genetic regions were too complex to be deciphered by the technology available at that time. In all, more than 100,000 gaps in the genetic sequence remained to be filled.
“Our team drew on the latest technology, plus the particular expertise of the individual team members, and that finally made possible the mapping of the complete corn genome,” Schnable said. In that first study, scientists had been able to map the centromeres — the complicated middle portions of chromosomes — for only two of corn’s 10 chromosomes, for example. Schnable and his colleagues were able to sequence all 10.
Schnable focused on regions of the corn genome containing genes called nearly identical paralogs: two or more genes located next to each other that are so similar it was hard or impossible to tell them apart in previous genomic-mapping efforts. Genetic repetition takes on extraordinary complexity in the corn genome, resulting in large areas of chromosomal material packed together in ways that have defied individual identification and analysis.
With this new complete analysis of a much-studied corn line known as Mo17, Schnable said, “we’re now able to resolve each of those individual genetic copies and start to do a better job of figuring out what individual genes do, rather than having all this combined into a mishmash where it’s hard to figure out which gene is doing what.”
The idea for this international project originated with Chinese researchers. Schnable has known Jinsheng Lai, a Chinese scientist and the paper’s lead author, for more than a decade, going back to when Schnable was a postdoctoral researcher at the Chinese Academy of Agricultural Sciences. “When he was putting this project together, he reached out to me to participate because of my expertise in this field,” Schnable said.
Source: unl.edu
Photo Credit: gettyimages-songdech17
Categories: Nebraska, Crops, Corn