Tandem duplication contributed to adaptation to plateau
environment
Although Orinus and Cleistogenes shared the same
paleo-allotetraploidy event, O. kokonorica has experienced severe
gene loss (large number of contracted gene families) compared withC. songorica during its adaptation to the high plateau. We found
only 47.82% (23,240) of gene duplications resulted from WGD/segmental
duplication. There was a considerable number of duplicated genes
generated from dispersed duplication (22.37%, 10,873), proximal
duplication (5.10%, 2477) and tandem duplication (4.10%, 1993) (Figure
2D). We found that the tandem duplicated genes in O. kokonoricawere enriched in many GO terms related to adaptation to the plateau
environment, such as ‘cellular response to oxygen levels’, ‘leaf
senescence’, ‘aging’, ‘programmed cell death involved in cell
development’ and ‘defense response’ (Figure 2E).