The maize (corn) genome sequence is now complete.Iowa State University (ISU) Plant Sciences Institute (PSI) researchers developed methods for the assembly of sequence data and conducted much of the ongoing functional analysis work as part of a multi-institutional, $29.5 million, National Science Foundation-funded effort. PSI researcher and agronomist Patrick Schnable coordinates a team of researchers now using these data to address multiple biological questions.What the effort has so far revealed is a genome nearly as large as that of the human, containing about the same number of genes but substantially more compelx. Its dramatic complexity tested the resolve of the genome assemblers as never before due to an unprecedented number of long strings of repetitive sequence and highly conserved transposable elements-restless chunks of DNA that jump around within the genome during normal cell division. They restructure the genome, generate genetic diversity and influence gene expression patterns. Eighty-five percent of the genome consists of these repetitive pieces that provide clues to the mysteries of genetic variability and gene function.
The maize line selected for sequencing is B73, an Iowa State-originated inbred line that was highly prized for making hybrids that are used for food, feed, and a variety of industrial feedstocks, including fuel. B73, released in 1972, was the product of breeding efforts by ISU agronomy professor emeritus Wilbert Russell.
The sequence in hand is but a starting point for plant scientists, yet speaks volumes for the possibilities it stores. Within this tome lie secrets for improving agronomic efficiency that will save growers on input costs and also has potential to improve water quality. It also equips researchers with an important model for understanding the biology of dedicated biofuel grasses.
"Thereal value of a sequenced genome is that it provides us with a reference from which to assess whether naturally occurring sequence variability among individuals is responsible for differing abilities to adapt to environments. Once we recognize and understand these patterns, we will have the ability to rapidly develop diverse maize hybrids that can fit the management practices and environmental scope that corn producers experience," says William Beavis, George F. Sprague Endowed Chair of Population Genetics and interim director of ISU's Plant Sciences Institute.The maize (corn) genome sequence is now complete..