- Researchers analysed DNA sequences from faecal samples of ibex collected from Jammu & Kashmir and Himachal Pradesh and found that they are genetically different from Siberian ibex found in all other ranges.
- So far, ibex populations in India are considered as one of the populations of the Siberian ibex.
- However, experts say it is difficult to draw conclusions from this limited study and overall, much more research will be needed to understand if ibex in the trans-Himalayas might be a separate species.
Siberian ibex, large goats with curved horns, are found in diverse mountainous habitats in central Asia such as Russia, Mongolia, Southern Siberia, China, Kazakhstan, Kyrgyzstan, Tajikistan, Afghanistan, Pakistan, and India. Now, a genetic analysis by a team of scientists from the Zoological Survey of India based in Kolkata appears to show that ibex found in Tajikistan and in the trans-Himalayan ranges of the union territory of Jammu & Kashmir and the state of Himachal Pradesh, also known as Himalayan ibex, are different from Siberian ibex in other regions. They believe that this population may, in future, be considered as a separate species, but experts say much more research is needed.
So far, ibex populations in India are considered as one of the populations of the Siberian ibex (Capra sibirica) distributed at the edges of its species range. But this study shows that ibex in India and Tajikistan are adequately diverged from those found in the Altai mountains, Russia, Mongolia and Kazakhstan, said Mukesh Thakur, scientist and senior author of the study. “We hope these pioneer efforts will grab global attention,” said Thakur, adding that they plan to collect more samples in India to understand whether Siberian ibex is a species complex.
Typically inhabiting elevations between 500 to 6700 metres, these wild goats have adeptly adapted to cold deserts, rocky outcrops, steep terrain, flats, ridges, and foothills. The herbivorous goats are found from western Mongolia to Altai, Hangai, Gobi-Altai, the Hurukh mountain ranges, and Sayan Mountains near the Russian border; scattered populations also exist in the shallow mountains of the Trans-Altai Gobi.
Thakur said that this study highlights that although Siberian ibex have a widespread distribution, it is not a single species genetically and is likely “two species or three to four subspecies lumped into a species complex.” Ibex tend to live in small groups of about 6 to 30 and forage in the evenings and mostly in the early morning hours. Males tend to have longer horns and beards than females.
“This is an interesting study but only a first step in the process of understanding whether the ibex in the Himalaya are a separate species from the Siberian ibex,” said Kulbhushansingh Suryawanshi, a scientist at the National Conservation Foundation (NCF) based in Mysuru, who was not involved in the study. “This study has found an interesting result, in that, the samples from the Himalayan ibex are more similar to the Nubian ibex from Arabia than to its own cousins from Central Asia.”
Mountainous landscapes can serve as a barrier resulting in the geographical isolation of a population of a species for long periods of time (such as millions of years). This, in turn, drives reproductive isolation which can lead to speciation — that is, the creation of a new and distinct species.
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The study is part of a project under the National Mission on Himalayan Studies to monitor threatened vertebrates in Indian Himalayan Regions.
The team collected 30 faecal samples from Lahaul, Spiti in Himachal Pradesh and extracted the DNA, focusing on a partial fragment of a gene found in mitochondria — organelles inside cells that are inherited maternally and are responsible for producing energy. In their analysis, they included sequences available for Siberian ibex from other ranges such as Mongolia, Russia, Kazakhstan, Kyrgyzstan and Tajikistan.
“The samples collected from India clustered with the sequences from Tajikistan in a phylogenetic analysis, which were adequately different from the other two clades: KZ clade of Kazakhstan (which broadly represents one of the clusters in the phylogeny) and AMR clade of Altai Mountains, Mongolia and Russia,” explained Thakur.
The researchers were surprised by the results, which suggested that ibex found in India to Tajikistan diverged relatively recently from Alpine and Nubian ibex. According to the analysis, India-Tajikistan clade, which is currently known as Siberian ibex, was estimated to have diverged from Alpine ibex 2.4 million years ago, during the early Pleistocene epoch, than the Siberian ibex during the Miocene-Pliocene boundary (6.6 million years ago).
More research needed
Sandro Lovari, professor at the Università di Siena, Italy, and Co-chair of the IUCN SSC Caprinae Specialist Group (wild sheep and goats) cautioned that DNA extracted from faecal samples “does not allow the extraction of long sequences of genes, which in turn affects the number of sequenced bases.” Consequently, he said that “no solid conclusion can be drawn.” Additionally, Lovari found “the existence of an ibex population close to the European Alpine ibex Capra ibex ibex, but in the very middle of Asia,” quite surprising.
Ibex distributed around the world look mostly the same apart from minor details and have the same behaviour, same chromosome number, and their skeletal bones are similar as well, explained Lovari. “Up to some 20 years ago they all belonged to one species Capra ibex, with many subspecies (geographic populations which show mild differences, but not affecting the production of fertile crossbreds). In the late ’90s, geneticists split Capra ibex into some 5-6 species by up-grading former subspecies to species level.”
Suryawanshi from the NCF said that this study uses very small amounts of data from the mitochondrial DNA, which, he explained, is “handed down entirely from the mother to her offsprings.” As males do not contribute mitochondrial DNA to the next generation, he said that “any story coming from only mitochondrial DNA is only half the story.”
He added: “This study will surely lead to further work to understand ibex as a ‘species complex’. There is a lot more to understand here than just whether Himalayan ibex is a separate species.”
Thakur’s team hopes to unravel the complexity of species recognition of ibex found in India and they are “now collecting samples from the entire distribution range in India and will undertake whole-genome analysis of the Himalayan Ibex.” In the future, he is also considering extending the study to “sequence all the species in the genus Capra to understand the evolutionary history of this genus.”
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Banner image: A Himalayan ibex at Spiti valley, Lahaul-Spiti, Himachal Pradesh. Photo by Mukesh Thakur.
