Global team looks at wheat’s DNA for ways to improve cropConsidered by some to be the Mount Everest of crop genomes, the challenging wheat genome is close to being scaled.
By: ELIZABETH PENNISI, ScienceNOW
Considered by some to be the Mount Everest of crop genomes, the challenging wheat genome is close to being scaled. An international team has produced a draft of wheat’s DNA sequence, one that identifies many of its genes and has made possible the identification of thousands of potential genetic changes that could improve this key crop.
“A tremendous resource for wheat improvement and plant genetics has been developed,” says Jeffrey Bennetzen, a plant geneticist at the University of Georgia, who was not involved with the work.
Wheat is the world’s most widely grown crop, and it feeds a substantial portion of the world’s population. But scientists have struggled to get a grip on its complex genetics. One complication is that the two kinds of wheat — bread wheat and pasta wheat — have different DNA makeups. Pasta wheat (durum), which is a hybrid of two wild grasses, has two genomes, one from each of its ancestors.
Bread wheat is even more complex: It has three genomes, the result of pasta wheat hybridizing with a third grass species. The new study, published online Wednesday in Nature, focuses on the bread wheat genome.
The bread wheat has almost six times as much DNA as the human genome. Unlike corn, which melded two ancestral genomes into one, bread wheat passes each of its three genomes to the next generation intact.
“Since wheat has three related genomes, a big problem has been to work out which gene comes from which genome,” says Peter Langridge, a plant geneticist at the University of Adelaide in Australia who is not involved with the study.