In this week's Science, researchers present new insights into the bread wheat genome. In one of four reports, a team from the International Wheat Genome Sequencing Consortium (IWGSC) report bread wheat’s draft gene sequence, which was generated using chromosome-based shotgun sequencing and assembling each chromosome arm of a cultivated wheat variety called Chinese Spring. The researchers pinpointed the location of more than 120,000 genes, including ones related to grain quality, pest resistance, and abiotic stress tolerance. In another paper, IWGSC and collaborators provided a reference sequence for the largest of the plant's 21 chromosomes, identifying high levels of gene copy number variation and thousands of important genetic markers. In the two final publications, one group leveraged wheat's draft sequence to better understand the phylogenetic history of modern bread wheat, which arose from crosses between three different species, and another cataloged RNA products of tissues from developing bread wheat grains to understand how the three subgenomes that contribute to modern bread wheat’s genome affect its gene expression.
GenomeWeb Daily News has more on the wheat genome papers here.
Also in Science, a report highlights how alternative splicing can result in unexpected protein products from well-understood genes. Scientists from the US and China focused on a family of enzymes called AARS, which deliver amino acids to compatible transfer RNA molecules, and analyzed proteins from alternatively spliced AARS genes, discovering many different forms of protein products that, in many cases, were no longer involved with tRNA. Rather, these variants were associated with distinct cellular processes, suggesting that they performed unique functions.
Finally this week, researchers from various institutes sound off on the potential use of gene-editing technology such as CRISPR-Cas 9 to design inheritance-biasing genes with the potential to drive certain traits through populations — so-called gene drives. Although gene drives have vast potential, they have not been implemented outside of the laboratory setting, and the authors urge public discussion and evaluation of the approach before advancing into wild populations where they could have unintended consequences.