For the fi��rst time, the ge-nome of the Royal Bengaltiger, an endangered bigcat, has been sequencedas part of plans to gener-ate a high-quality draft ge-nome sequence of the ani-mal. Althoughendangered and threa-tened by various extinc-tion risks, this tiger sub-species is the mostpopulous one with thehighest genetic diversityand the strongest chanceof survival in the wild.

The high coverage ge-nome sequencing andidentifi��cation of genomevariants in Bengal tiger(Panthera tigris tigris)were carried out by scien-tists from the Centre forCellular and MolecularBiology (CSIR-CCMB) anda Hyderabad-based priv-ate company. The detailsof the study were pu-blished online in BioRxivrecently. This genomewas compared with thegenome of Amur or Siber-ian tiger. These two sub-species occur in diverseenvironments and thenew data also reveals ma-jor variations between the

two. While Amur tiger oc-curs exclusively in sub-temperate and snow-co-vered habitats, the Bengaltiger occupies diversetropical habitats rangingfrom Himalayan foothillsto Central India plateauand the Western Ghats.

Genome data providesan insight into the geneticdiff��erences at individuallevel — ranging from sin-gle nucleotide variationsto large structural var-iants. It also provides abetter understanding ofhow the gene variantsplay a role in adaptationto the environment anddisease susceptibility. Inother words, it will revealthe changes triggered inthe genes due to the adap-tability to diff��erent envi-ronments in the evolu-tionary time scale.

The study observed“For a very long time itwas believed that singlenucleotide variants(SNVs) contribute to a ma-jority of the individual ge-nomic variations. Now itis recognized, albeit poor-ly understood, that muchlarger changes in the ge-nome like structural var-iants and copy numbervariants also contributesignifi��cantly to diseasesusceptibility, phenotypicvariations andimmunity”.

The researchers claimthat this is the fi��rst reporton the discovery of copynumber variants andlarge structural variantsin the genome of a wild,endangered species. Thecomprehensive data ofBengal tiger and Amur tig-er genome sequences

“will initiate our under-standing on genomicchanges and the speciesability to adapt to discreethabitats”, the scientistswrite.

The identifi��cation ofnumerous Simple Se-quence Repeats (SSRs)will help in gaining a bet-ter insight into populationgenetics and gene fl��ow.Dr. P. Anuradha Reddy,the lead author of thepaper said that the nume-rous SSRs and SNVs iden-tifi��ed in the genome canbe used to strengthen fo-rensic evidence in tigerpoaching cases.

Such studies will alsohelp in improving conser-vation management asauthorities attempting torelocate an endangeredanimal will have a betterunderstanding of its adap-tability to the newenvironment.

CCMB Director, Dr. Ra-kesh Mishra said that ge-nome sequencing willhelp in precise under-standing of the evolution-ary linkage of the organ-ism. Besides, epigeneticanalysis becomes possibleonce the genome is availa-ble.

Royal Bengal tiger genome sequenced It will help in precise understanding of tiger's evolutionary linkageY. Mallikarjun

The genome data can be used for strengtheningforensic evidence in tiger poaching cases.