For the first time, the entire genome of Asiatic lion, an endangered species, has been sequenced by scientists from CSIR-Centre for Cellular and Molecular Biology, Hyderabad.
De novo sequencing and annotation have resulted in a draft assembly of the entire genome of a male Asiatic lion. “This firsthand information would help us to better understand the evolution of Asiatic lions and also make possible comparative analysis with other big cats,” says Dr. Ajay Gaur, the lead author of the study, which was recently published online in BioRxiv, the pre-print website.
With the complete genome of royal Bengal tiger, African Cheetah and Jaguar available, comparative studies of all these big cats would be possible. He said only partial genomic information of the African lion was available now. Comparative genomics between African and Asiatic lions could be undertaken once the complete genome of the African lion is sequenced.
The population of the endangered Asiatic lion is very low — only 523 animals are present in the Gir forests. The genome sequencing would enable scientists to develop specific markers to study population genetics (the differences at the gene level within a population) and get newer insights into its population status and subsequent management.
Comparative analysis with other felids and mammalian genomes unravelled the evolutionary history of the Asiatic lion and its position among other felids. The study noted that the evaluation of genetic diversity placed the Asiatic lion in the lowest bracket of genomic diversity index highlighting the gravity of its conservation status.
The genome is estimated to be 2.3 Gb (Gigabase) long and is found to have 20,543 protein-coding genes.
Dr. Gaur says that they found several candidate genes which are up-regulated in Asiatic lion and a few of them were specific to males.
As regards the crucial aspect of conservation of Asiatic lions, he says there is a need to adopt a multi-pronged approach and the study will enable better disease and population management of the endangered big cat by identifying characteristics which are specific to Asiatic lions.
CCMB Director, Dr. Rakesh Mishra says candidate genes which are specific to Asiatic lion can be identified by comparing with other big cats. The final objective is to understand the species at DNA level and study if there are any specific problems with regard to adaptability to environment or behaviour vis-à-vis other big cats.