利用肝脏转录组数据分析地山雀的适应性进化

To Analyze the Molecular Adaptation of the Tibetan Ground Tit Using Liver Transcriptome Data

肝脏是生物新陈代谢的重要器官。为了探究青藏高原特有鸟类地山雀(Parus humilis)如何适应低温、低氧等恶劣环境,我们对其肝脏转录组数据进行分析,并结合斑胸草雀基因组数据进行了比较研究。结果显示,地山雀肝脏转录组中的大部分高表达基因都直接参与机体的新陈代谢活动;通过与斑胸草雀基因组数据进行比较,对筛选出的214个快速进化基因进行代谢通路的功能富集,发现多数基因富集到与能量代谢、免疫反应和消化相关的通路上。本研究表明,高表达基因的功能一方面验证了肝脏是机体新陈代谢的主要场所,参与胆汁分泌、脂肪酸的转化及解毒等多项生理活动;另一方面也说明这些高表达基因对于维持肝脏的正常功能是必要的。快速进化基因的功能富集分析揭示了地山雀中与能量代谢、免疫反应和食性等相关的基因受到自然选择压力的影响而发生了适应性的快速进化。

The liver is a vital metabolic organ in organisms. In order to examine the evolutionary mechanism of adaptation to the extreme environment with low temperature and low oxygen concentration, the liver transcriptome data from the Qinghai-Tibetan Plateau endemic bird, the ground tit （Parus humilis） was analyzed and compared with the zebra finch＇s draft genome. Our results showed that the vast majority of the highly expressed genes in the ground tit had been involved in metabolic processes. In comparison with the genome data of zebra finch, we obtained 214 rapidly evolved genes, most of which were enriched to KEGG pathways associated with energy metabolism, immune response, and digestion. Our analysis of highly expressed genes confirmed that the liver is the location of many important metabolic processes in organisms, such as bile secretion, fatty acid conversion and detoxification, and also suggested that these genes are essential in maintaining the basic hepatic functions in organisms. Our analysis of rapidly evolved genes revealed that adaptive evolution and natural selection have acted on those genes associated with energy metabolism, immune response and digestion.