Centromeres on three corn chromosomes.

University of Hawaiʻi at Mānoa researchers contributed to an historic release of a new, high-quality corn reference genome sequence that shows reasons why corn can be adapted to such a wide variety of growing conditions. Professor Gernot Presting and two postdoctoral scholars in his lab, Kevin Schneider and Thomas Wolfgruberare, are members of Department of Molecular Biosciences and Bioengineering in the College of Tropical Agriculture and Human Resources.
 
Researchers at the Cold Spring Harbor Laboratory in New York and the U.S. Department of Agriculture led the sequencing effort, which involved laboratories at UC Davis, the University of Georgia, the University of Minnesota and biotechnology companies. Their findings have been published in the journal Nature.
 
“Flexible” genome leads to adaptability
 
Genome analysis has become an indispensable tool for plant improvement by breeding. The newly released sequence fills in ~100,000 gaps left in the initial genome sequence released in 2009. This additional information leads to a much fuller understanding of the genetic structure of this culturally and economically important crop. Most significantly, the findings show that the corn genome is very “flexible,” or adaptable. This flexibility will have potential benefits in the advent of climate change.
 
The significance of the centromere
 
This genome assembly includes a high-quality sequence of many corn centromeres. Members of the Presting laboratory have previously determined the nucleotide sequence of corn centromeres, which play an essential role in cell division by ensuring that each new cell obtains a complete set of chromosomes. On the X-shaped chromosome, the centromere is at the “cross” point of the two arms. Like the rest of the chromosome, centromeres are composed of double-stranded DNA and protein, but have been very difficult to sequence because they are composed of highly repetitive DNA. Presting said, “This new genome has already been tremendously useful in confirming and extending our understanding of centromere evolution and will undoubtedly help us clarify the function of the repetitive DNA that is typical of centromeres.”