NEW YORK, July 21 - The Maize Mapping Project -- a collaboration between the University of Missouri-Columbia, the University of Arizona Genomics Institute, and the University of Georgia -- has completed the first phase of an integrated genetic and physical map for the corn genome.
The NSF-supported project, which is anchoring ESTs and other markers to both the physical and genetic maps of the maize genome, recently concluded the first of three scheduled phases, said Ed Coe, a geneticist with the USDA/Agricultural Research Service at the University of Missouri and principal investigator. Phase I entailed both computational assembly of BAC contigs as well as a manual curation step that reduced the total number of contigs from around 300,000 to a "workable number" in the neighborhood of 3,000, Coe told GenomeWeb.
The maize genome has approximately 2.5 billion base pairs arranged into 10 chromosomes. "Half of the total DNA [in the maize genome] is pinned down now," said Coe.
The five-year mapping project is scheduled to end in September. Phase II will entail further manual editing of the genetic and physical maps, and Phase III will use comparative genomics to gain further knowledge about the maize genome by comparing it to the genomes or rice and sorghum, Coe said.
"This is the most exciting phase for our project because we're seeing it all come together after a period of slow, step-wise progress," said Coe.
The BAC contigs and genetic/physical anchoring are available at two sites: www.genome.arizona.edu/fpc/maize/ and www.maizemap.org/iMapDB/iMap.html.
The physical and genetic maps will provide the groundwork for large-scale maize genome sequencing projects. The NSF began awarding maize sequencing grants in the fall as part of a broad plant genomics initiative: A two-year project led by Rutgers University received a $4.3 million NSF grant to sequence 20 million base pairs of the maize genome; while a project led by the Donald Danforth Center in St. Louis was awarded $6 million for a two-year project focusing on sequencing gene-rich regions of the maize genome.