August 9, 2013, Shenzhen, China - In a study published in Cell Research, Chinese scientists from Zhejiang University and BGI have completed the genome sequencing and analysis of the endangered Chinese alligator (Alligator sinensis). This is the first published crocodilian genome, providing a good explanation of how terrestrial-style reptiles adapt to aquatic environments and temperature-dependent sex determination (TSD).
The Chinese alligator is a member of the alligator family that lives in China. It is critically endangered with a population of ~100 wild and ~10,000 captive individuals in Zhejiang and Anhui Provinces. Great efforts have been put into uncovering the mysteries of this species because of its unique features that allow them being adapted for living in both water and land habitats.
In this study, researchers collected a Chinese alligator sample from Changxing Yinjiabian Chinese Alligator Nature Reserve (Zhejiang Province, China) and sequenced its genome using a whole-genome shotgun strategy. The genomic data yielded a draft sequence of Chinese alligator with the size of 2.3 Gb, and a total of 22,200 genes were predicted.
The genomic data provides a strong evidence from DNA level to illustrate why Chinese alligator can hold its breath under water for long periods of time, such as the duplication of the bicarbonate-binding hemoglobin gene, positively selected energy metabolism, and others. Researchers further identified the genetic signatures of the powerful sensory system and immune system of Chinese alligator. All the results presented evidence for co-evolution of multiple systems specific to the back-to-the water transition.
Chinese alligator exhibits TSD, and does not possess sex chromosomes. The absence of sex chromosomes is another interesting feature. In this study, researchers analyzed the evolutionary mechanism of sex chromosomes, and reported that the alligator was the first TSD species whose genome has been sequenced, which will have great implication in resolving sex chromosome evolution.
Shengkai Pan, Project manager from BGI, said, "The accomplishment of the Chinese alligator genome is significant for understanding its adaptation for both aquatic and terrestrial environments, and more importantly, for the conservation of such an endangered species."
BGI was founded in 1999 with the mission of being a premier scientific partner to the global research community. The goal of BGI is to make leading-edge genomic science highly accessible through its investment in infrastructure that leverages the best available technology, economies of scale, and expert bioinformatics resources. BGI, which includes both private non-profit genomic research institutes and sequencing application commercial units, and its affiliates, BGI Americas, headquartered in Cambridge, MA, and BGI Europe, headquartered in Copenhagen, Denmark, have established partnerships and collaborations with leading academic and government research institutions as well as global biotechnology and pharmaceutical companies, supporting a variety of disease, agricultural, environmental, and related applications.
BGI has established a proven track record of excellence, delivering results with high efficiency and accuracy for innovative, high-profile research which has generated over 250 publications in top-tier journals such as Nature and Science. These accomplishments include sequencing one percent of the human genome for the International Human Genome Project, contributing 10 percent to the International Human HapMap Project, carrying out research to combat SARS and German deadly E. coli, playing a key role in the Sino-British Chicken Genome Project, and completing the sequence of the rice genome, the silkworm genome, the first Asian diploid genome, the potato genome, and, most recently, have sequenced the human Gut metagenome, and a significant proportion of the genomes for 1,000 genomes. For more information about BGI please visit http://www.