Is Tibetan Qingke Barley a Member of Common Barley Family Based on Comparative Genomic Evidence

Tibetan Qingke barley is the staple food of the Tibetan people. It has been cultivated on the Qinghai-Tibetan Plateau for about 3 500 years. Tibetan Qingke barley is a variety of naked barley (Hordeum vulgare linn.var.nudum) belonging to the Hordeum of the family of Gramineae. Unlike other barley, Tibetan Qingke barley has fully adapted to the extreme plateau climate after being domesticated and cultivated on the Qinghai-Tibet plateau for up to 3 500~4 000 years. The researchers sequenced and mapped the whole genome of a local Tibetan variety-Lasa Garma-guri, and obtained a gene map with a size of 3.89 Gb, containing a total of 36151 protein-coding genes. The genome data with a size of 4.79 Gb was obtained by sequencing the whole genome of a US spring six-row malting barley-Morex and a total of 83105 putative gene loci were identified. The Morex genome was mapped into the genome of Lasa Goumang, with a coverage rate of 92.89%. Compared with 26 159 gene sets with high confidence in Morex genome, although these genes in highland barley are greatly similar to barley genes, the length of about 10.97% of the genome in highland barley is significantly longer than that of Morex. The researchers further compared Tibetan Qingke barley genomes with those of other gramineae crops and found that Tibetan Qingke barley was isolated from Aegilops tauschii (Ae. tauschii), Triticum urartu (T. urartu) and Triticum aestivum (T. aestivum) about 17 million years ago. Further analysis by the researchers found that a large number of sequences in the genome of modern Tibetan Qingke barley are still similar to Ae. Tauschii, T.urartu and T. aestivum, and the number of similar gene families is as high as 18849.