An international team of scientists led by Dr Eduard Akhunov of Kansas State University has created the first haplotype map of wheat that provides detailed description of genetic differences in a worldwide sample of wheat lines.
Wheat fields in Lviv region, Ukraine. Image credit: Raimond Spekking / CC BY-SA 3.0.
Plant scientists often look at the genetic makeup of an organism to breed new varieties for specific, desirable traits, such as drought, pest or disease resistance.
The haplotype map gives them quick access to rich, genetic variation data that increases the precision of mapping genes in a plant genome, and improves scientists’ ability to select the best lines in breeding trials.
In their study, Dr Akhunov and his colleagues analyzed 62 wheat lines from around the world that were either modern cultivars or varieties not previously improved through formal breeding techniques.
To reduce the complexity of the wheat genome, the scientists developed a tool called exome capture assay to perform targeted sequencing of only functional parts of the larger wheat genome. This technique bypasses those parts of the genome that are repetitive.
The researchers found 1.6 million locations – called single nucleotide polymorphisms – in the genome where the wheat lines differed from one other. They used this information to describe the impact of these differences on the function of tens of thousands of wheat genes.
“Once genes controlling agronomic traits are identified, they can be used for improving wheat using not only traditional breeding approaches, but also new strategies that are based on biotechnology and molecular biology,” said Dr Akhunov, who is the senior author of the paper published in the journal Genome Biology.
“In the future, we will expand the set of wheat lines characterized using our sequencing strategy by including not only more genetically and geographically diverse wheat lines, but also by including close and distant relatives of wheat.”
“These wheat relatives are known for being a reservoir of valuable genes for agriculture that can improve abiotic and biotic stress tolerance or other quality traits, and increase yield.”
“Genomics-based approaches are now being introduced into every wheat breeding program worldwide,” Dr Akhunov said.
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Katherine W Jordan et al. 2015. A haplotype map of allohexaploid wheat reveals distinct patterns of selection on homoeologous genomes. Genome Biology 16, 48; doi: 10.1186/s13059-015-0606-4
