Citizen conservationists spotted the hybrids in grasslands in and around Pune in Maharashtra. Credit: Siddhesh Bramhankar/ The Grasslands Trust
A new study offers the first genetic evidence of hybridisation1 between wolves and feral dogs in the Indian savannahs, raising questions over the future of wild wolf packs. The findings also highlight the value of next-generation sequencing in collecting samples non-invasively as an efficient tool to detect hybrids.
A citizen science project prompted scientists to study hybridisation between grey wolves (Canis lupus) and feral dogs (Canis lupus familiaris).
Citizen conservationists of Grasslands Trust in Maharashtra’s Pune district have been following wolf packs in and around Pune for a decade. Their records showed that some animals in the packs appeared different from the rest. Tawny with black tail tip, these individuals moved with the pack and followed their social structure. One was even seen fulfilling the assigned role of the male parent of a litter, said Mihir Godbole, the trust founder.
“In a wolf pack, only one pair of wolves mates and reproduces. Fathers are involved in taking care of the litter,” said Godbole. The hybrids were spotted in four districts in Maharashtra — Dhule, Ahmednagar, Nashik and Pune.
Scientists at the Ashoka Trust for Research in Ecology and Environment (ATREE) and National Centre for Biological Sciences (NCBS) followed up on the observations to determine the probability of hybridisation using genetic analysis via non-invasive sampling.
“It was a rare case of citizens' observation motivating science. We used scientific tools to find answers,” said Uma Ramakrishnan of NCBS. The study was probably India’s first evidence-based documentation of wolf-dog hybridisation.
Generally, in mammals, only hybrid females are fertile while hybrid males are not. Among canids, earlier studies2 have shown that both sexes of hybrids are fertile and capable of reproduction. This enables the introgression of dog genomes into wolves and vice versa, said Abhinav Tyagi, one of the authors of the study.
Extinction possibility
There are concerns that an increase in the population of hybrids and gradual decrease in the numbers of pure breeding members can disrupt the social structure of wolves. This can further drive hybridisation, leading to a 'hybridisation vortex’, and eventually to extinction of a species.
Wild canids like grey wolves and golden jackals (Canis aureus) often live closer to human habitations and coexist with domestic dogs in a complex relationship of competition.
Increased human-wildlife interfaces have resulted in more interactions between the two species. Researchers say hybridisation could result in significant reduction of specific adaptations in wolves, which combined with increased exposure to canine diseases such as rabies, distemper, and parvoviruses, could lead to a reduction in wolf populations.
Using SNP markers
For the study, hairs were collected from two different looking individuals in Pune and their genetic origin investigated and compared against other canid species like golden jackals and dholes (Cuon alpinus).
The study found the first genetic evidence of one second generation or F2 hybrid and another individual that “could be a complex hybrid between dogs and wolves”.
In place of mitochondrial DNA and microsatellite markers, the scientists used the more advanced single nucleotide polymorphism (SNP) markers, that identify hybrids more efficiently.The findings also challenge the definition of ‘biological species’. Wildlife acts and legislations around the world do not account for hybrids. “This study should encourage more evidence-based action, research and policies for conservation of hybrids,” said Ramakrishnan.
The Grasslands Trust has proposed sample collection from across Maharashtra by the state’s forest department to gauge the extent of hybridisation.
