We asked one of the co-authors, Ian Dawson, who’s an old friend, to briefly summarize for us a paper just out in New Phytologist on the domestication of barley. Here is his contribution. Thanks a lot, Ian, and keep ’em coming…
The power of new technologies to explore crop evolution is illustrated by a just released paper by Russell and co-workers ((Russell, J., Dawson, I., Flavell, A., Steffenson, B., Weltzien, E., Booth, A., Ceccarelli, S., Grando, S., & Waugh, R. (2011). Analysis of 1000 single nucleotide polymorphisms in geographically matched samples of landrace and wild barley indicates secondary contact and chromosome-level differences in diversity around domestication genes New Phytologist DOI: 10.1111/j.1469-8137.2011.03704.x)) that explores barley domestication in the Fertile Crescent, a key region in the development of farming. From assessing a collection of more than 1,000 genetically mapped, genome-wide single nucleotide polymorphisms (SNPs) in geographically-matched landrace and wild barley accessions from Jordan and Syria, genetic contact between the two categories was evident, suggesting hybridisation may be a mechanism for the continued adaptation of landraces in the region under climate change. In addition, statistically significant chromosome-level differences in diversity between barley types were observed around genes known to be involved in the evolution of cultivars, indicating regions of the genome that may be subject to selection and therefore of interest in future crop breeding. For example, a significant reduction in diversity in landrace barley –- which suggests a genetic bottleneck during domestication –- was observed around the brittle rachis genes, recessive characters which result in grains remaining longer on plants after maturation, allowing efficient harvest of cultivated compared to wild barley. Jordan and southern Syria, compared to the north of Syria, was supported by SNP data as a more likely origin of domesticated barley, suggesting limited locations for the original development of the cultivated crop. Such studies, which exploit novel and rapidly developing genotyping methods, provide great scope for also exploring the evolution of other crops of both historical and current importance, especially when combined with matched geographic sampling of wild and cultivated material.