17/09/2017
Blog by Dr Mumtaz Baig, Group Leader, LMCG, Amravati, on genetic conservation of Indian Wild Ass (Equus hemionus khur).
Don’t be deceived by numbers in conservation: Lesson from Indian wild ass population genetics :
The Indian wild ass zoologically identified as Equus heminous khur belongs to the Asiatic stock of wild asses which were once roaming in continuous distribution from Arabian Peninsula to Manchuria. In all their distribution ranges in Asia, excessive hunting and ever shrinking habitat had pushed them to the endangered status. Currently, 4900 km2 Indian wild ass sanctuary carved out in little and Greater Rann of Kutch, Gujarat, India is the last refugia of these 4000 Indian wild ass population in southern Asia. Though hunting and poaching has not been reported for this wild Equid species and conservation efforts led to a significant increase in their number after the devastating protozoic disease surra wiped out most of the population and leaving just 350 surviving individuals in the year 1962. But measuring genetic diversity is of grave importance for conservation and management of wildlife. Using mitochondrial DNA and nuclear microsatellite markers, for the first time, we accessed the genetic diversity of free-ranging Indian wild asses to understand the underlying principles of population genetics operating in this isolated endangered wild population. Both mitochondrial and microsatellite analyses revealed low genetic diversity marked by single haplotype found in cytochrome b and D-loop region as well as average expected heterozygosity of 0.474 found by genotyping five microsatellite loci. Interestingly, the comparison of present and past demography using Bayesian markedly revealed steady decline in effective population size of Indian wild asses in Indian subcontinent after the origin of agriculture and rise of Indus valley in the west of the subcontinent. In recent years, the Indian wild asses have expanded their range as their presence is confirmed outside Rann of Kutch for example in Surendra Nagar district of Rajasthan. Even though their number is increasing, measures to enhance genetic diversity of this isolated population should be taken because the danger of attaining inbreeding depression and decrease in fitness is always associated with such population. Our study also demonstrates that the Indian wild ass is genetically identical to Turkmenistan Kulan and Persian Onager, hence efforts to import some breeding individuals from these region should be taken to initiate out breeding program to enhance their diversity. Successful re-introduction of Turkeminstan kulan in Israel where it is successfully hybridizing with existing Persian onager manifest our view.
