UA Geneticists Help Solve Barley Genome Puzzle

Barley has more genes than humans. (Photo: Alexander von Halem)
Barley has more genes than humans. (Photo: Alexander von Halem)

Higher yields, improved pest and disease resistance and enhanced nutritional value are among potential benefits of an international scientific research effort that has resulted in an integrated physical, genetic and functional sequence assembly of the barley genome, as described in a paper published in the journal Nature.

“If you think of all the barley genes as a giant puzzle, you could say we can now see what picture the puzzle shows, how many pieces there are, what they look like and where they go,” explained Rod Wing, professor of plant sciences in the University of Arizona College of Agriculture and Life Sciences and director of the UA Arizona Genomics Institute.

Wing and several members of his lab are part of the International Barley Sequencing Consortium, or IBSC, a consortium comprised of many researchers at many institutions across the world. Wing's group is part of the UA BIO5 Institute

According to the IBSC, the new resource will facilitate the development of new and better barley varieties able to cope with the demands of climate change. It should also help in the fight against cereal crop diseases, which cause millions in losses every year.

"The barley genome will help us in our quest to help solve the ‘9 billion-people’ question: How to feed two more billion mouths in less than 40 years,” Wing said.

Knowing the entire sequence helps plant breeders select lines that contain desirable genes more rapidly than the conventional method of repeated crossing of strains followed by evaluation, Wing explained.

First cultivated more than 10,000 years ago, barley belongs to the Triticeae family – which includes wheat and rye – and that together provides around 30 percent of the calories consumed worldwide. It is the world’s fourth most important cereal crop both in terms of area of cultivation and in quantity of grain produced.

At 5 billion nucleic acid base pairs (the genetic “letters”), the barley genome is almost twice the size of that of humans, and determining the sequence of its DNA has presented a major challenge. This is mainly because its genome contains a large proportion of closely related sequences, which are difficult to piece together.

“The larger the genome, the more repetitive its sequence is,” Wing said. “If you perform a whole genome shotgun sequencing approach, 90 to 95 percent of the genome sequence you get consists of almost the same sequence over and over, with no order or orientation.”

Date released: 
Oct 24 2012
Rod Wing