Chinese scholars have made new progress in the field of genetic adaptation of birds on the Qinghai-Tibet Plateau

Figure Falcon colonization of the Qinghai-Tibet Plateau and its genetic adaptation mechanism model

With the support of the National Natural Science Foundation of China (grant number: 31930013, 32125005), the Zhan Xiangjiang research group of the Institute of Zoology, Chinese Academy of Sciences has made new progress
in the research of genetic adaptation of birds on the Qinghai-Tibet Plateau 。 The research results, titled "Arctic introgression and chromatin regulation facilitated rapid Qinghai-Tibet Plateau colonization by an avian predator," were published in Nature Communications on October 27, 2022.
(Nature
Communications) published online.
Links to papers: https://doi.
org/10.
1038/s41467-022-34138-3
.

The Qinghai-Tibet Plateau and the Arctic have a similar extremely cold climate, and it is unclear
whether there is gene flow related to low-temperature adaptation between the two polar species.
In addition, in addition to hypoxic adaptation, the genetic mechanism of how highland animals adapt to low-temperature, intense UV environments is still poorly
understood.
The researchers used Falco cherrug, a representative bird of prey on the Tibetan Plateau, and its Arctic relative, F.
rusticolus, as a model to study these mysteries
.
Population genome analysis
was conducted on 30 falcon individuals originating from the three main breeding grounds of Eurasia and 10 individual spear falcons from the Eurasian Arctic.
It was found that during the last Glacial Age (LGM), the spear falcon migrated south from the North Pole and crossed
with falcons in southern Siberia.
After LGM, falcon hunters colonized
the Tibetan Plateau.
This allowed the researchers to systematically study the rapid adaptive evolution of
falcons on the Tibetan Plateau.

In terms of low-temperature adaptation, highland falcons were found to be larger and heavier
than other falcons.
Two key genes infiltrated from Arctic spear falcons: SCMH1 and SCARB1
, were found in the genome of the highland falcon.
The infiltrated fragment on the SCMH1 intron has a stronger inhibitory effect, causing upregulation of HOX gene expression related to physical development, leading to an increase in falcon size (Figure).

The infiltrated SCARB1^C362T mutation is beneficial for highland falcons to remove more cholesterol from the blood and reduce the negative effect
of lipid increase in cold conditions.

In terms of hypoxia adaptation, multi-omics analysis was used to find that a DNA region with the strongest signal (500 Kb) in the genome of highland falcons still maintained a conserved three-dimensional spatial structure, but the interaction between its internal regulatory elements and hemoglobin genes was enhanced, which promoted higher expression of hemoglobin and responded to hypoxic pressure
.

In terms of strong UV adaptation, comparing the reflection spectrum of feathers, it was found that the feathers of highland falcons were darker
.
An intron region of the ASIP gene in the genome is positively selected
.
The enhancement effect of the high prototype fragment is attenuated, thereby reducing the expression of ASIP gene and promoting the synthesis of eumelanin, which may reduce UV damage
to highland falcons.

Combined with multi-omics analysis and functional experiments, this study found for the first time the genetic contribution of Arctic relatives to the adaptive evolution of animals on the Qinghai-Tibet Plateau, and systematically explored the genetic mechanism
of how plateau animals adapt to low temperature, low oxygen and strong ultraviolet (UV) stress.