WildFact
›
Information Section
›
Terrestrial Wild Animals
›
Wild Cats
›
Tiger
DNA samples of Bengal tigers polluted by genes of the Siberian Tiger
DNA samples of Bengal tigers polluted by genes of the Siberian Tiger
|
DNA samples of Bengal tigers polluted by genes of the Siberian Tiger
|
A controversy arises over the purity of the Indian tiger after DNA samples show Siberian tiger genes.
By Subhadra Menon Royal Bengal TigerBlue blood with a hint of A scandalous liaison? That is what a strand of hair and a DNA profile has indicated. A team of wildlife researchers has found the DNA samples of two Royal Bengal tigers (Panthera tigris tigris) from Dudhwa National Park in Uttar Pradesh "polluted" by genes of the Siberian tiger. Surrounded by feline DNA fingerprints, Lalji Singh, deputy director of the Centre for Cellular and Molecular Biology (CCMB), Hyderabad, who led the research team, says the findings are disturbing. "The genetic purity of the Indian tiger in Dudhwa will be lost," he warns, "and we will end up with a mixed-gene pool." The Royal Bengal is small and brilliant coloured -- tawny, golden yellow, with dark stripes -- and its fur sticks close to its body. It has pointed ears and a lean jawline. In comparison, the Siberian tiger -- hardly 200 of which survive in Russia's far eastern corner -- is the biggest of the five living tiger sub-species: the others being the South Chinese (P. tigris amoyensis), Sumatran (P. tigris sumatran) and the Indo-chinese (P. tigris corbett); the Caspian, Javan and Bali tigers are now extinct. The Siberian is a fine cat with rounded ears, a massive jaw, and thick, soft fur. The CCMB study has busted the myth that Indian tigers are genetically confined to their own pockets. Working on blood and hair samples from 22 tigers of "known wild origin" from all over the country, Singh studied the vital sequences of the DNA that are peculiar to each species. The readings showed around 21 per cent heterozygosity in Indian tigers, which means that the felines drew genetic characteristics from more than one gene pool. Much of the variation arose out of cross-breeding between tigers from the country's 23 tiger reserves. This low level of variation indicates inbreeding, given that the average variation in wild carnivores is 40 per cent. What is more, on analysing 50 to 125-year-old tiger skins from museum specimens, Singh found almost the same level of genetic variation. The two samples taken from Dudhwa were of tigers suspected to be hybrids. The genetic information obtained certainly related to the Siberian tiger. The big question is: where did the alien genes come from? The two tigers from Dudhwa could be the offspring of Tara, a tigress controversially released into the wilderness by wildlife enthusiast Billy Arjan Singh in the '70s. Questions had been raised in Parliament about Tara's origins and there was, at some point, the admission that she was not of Indian stock. "Since the 20 other samples showed no Siberian genes, it is possible that the genes came from Tara," says Lalji Singh. He, however, adds that two specimens constituted too small a sample base to conclusively prove that Tara was the source of Siberian genes. "Ideally, all the tigers in the Dudhwa region should be studied before a definitive statement can be made," he says. If not from Tara, who? There are some theories about the influx of foreign genes (see box). While the Himalayas effectively squashes the probability of tigers from India crossing over to China or Russia, it is possible that an Indian tiger mated with a Chinese tiger along the Myanmar tract. The Chinese tiger could, in turn, have inherited genes from a Siberian parent. Theoretically, tigers of unknown lineage which have escaped from zoos and circuses could also be the source of the Siberian genes. Will the Siberian genes then make the Royal Bengal a pale shadow of its majestic self? "The big cats are characteristically conservative in their breeding habits," says Ravi Chellam, scientist at Dehradun's Wildlife Institute of India. Which is perhaps why the Indian tiger -- anyway restricted to pockets in the tiger reserves -- has tended to breed within its distinctive population. Scientists are worried about inbreeding depression, where highly inbred animals become sterile, are susceptible to infections and lose their vitality. However, Chellam explains that inbreeding isn't a real problem unless the group shrinks to 50 individuals or less. This strengthens the case for out-breeding, which takes place, say, when a tiger from Corbett National Park in Uttar Pradesh mates with a tigress from the Sunderbans; in other words, when there is an influx of genes from populations other than the one immediately surrounding the animal. The cubs of such a union could show better resistance to diseases or enjoy a robust physique. This means that the Siberian gene could make the Royal Bengal tiger a bigger animal, if a less beautiful one. Lalji Singh's Siberian gene finding has people worried. "This kind of genetic pollution could affect the purity of the Royal Bengal stock," stresses R.L. Singh, chief wildlife warden of Uttar Pradesh. While there are many who thumb their noses at the argument about retaining the purity of the Indian tiger, it is in keeping with today's thinking. Maintaining the purity of wild gene pools is the current philosophy of conserving species. This is notwithstanding the fact that different species are known to interbreed in the wild. There is, for instance, a new species called the Brown Langur, the product of the mating between the Nilgiri Langur and the Common Langur. To a lot of experts, genetics lies on the fringe of conservation programmes. "The role of genetics in the endangerment of a species is highly exaggerated," says Ullas Karanth of the Wildlife Conservation Society of the US. He says that the ecological threats faced by vulnerable animals like the tiger are bigger worries. Still, the genetic identification of wild tiger populations is not something that can be ignored. Which is why Lalji Singh thinks he's only just begun an important task. He feels that immediate and extensive studies should be done on the genetic profiles of tigers in all the reserves of India. That, he says, can become the blueprint for action to save these great cats. Credit to Samkarma Sameer Puri 
Misleading Title
They tested 2 tigers out of thousands "The big question is: where did the alien genes come from? The two tigers from Dudhwa could be the offspring of Tara, a tigress controversially released into the wilderness by wildlife enthusiast Billy Arjan Singh in the '70s" But we still don'tknow how different Amur and Bengals really are, they have adapted to different climates and terrain, but both are pretty much identical in body size and such a small # with very little Amur genetics could most likely be stomped out over the generations and revert back to pure Bengal. Like the article states, "There are some theories about the influx of foreign genes (see box). While the Himalayas effectively squashes the probability of tigers from India crossing over to China or Russia, it is possible that an Indian tiger mated with a Chinese tiger along the Myanmar tract. The Chinese tiger could, in turn, have inherited genes from a Siberian parent. Theoretically, tigers of unknown lineage which have escaped from zoos and circuses could also be the source of the Siberian genes." The chances of that occuring are miniscule and if it did, its still a natural occurance outside of escaped zoo or circus tigers which to my knowledge none have ever lasted very long after escaping and if they did survive, their genes have already been in bengals for 100s of years.
May be, But if it is true. This may answer why modern bengal tiger exceed in size compared to Amur.
(06-18-2015, 10:07 PM)'sanjay' Wrote: May be, But if it is true. This may answer why modern bengal tiger exceed in size compared to Amur. That wouldn't be true either, as Bengal tigers have always been as large or larger than Amurs for as long as verified weights have been used. There is no time you can date back to where Wild Amurs were larger than Wild Indian Bengals. You would also need the genetic results of every tiger ever weighed to see if they had amur genes in them, then you would need to average the weight of ones that do compared to ones that don't. Since all but 2 do not and the two that do are related to a captive released tiger in one single area, its not likely and no other Bengals that have had blood samples taken have been reported to have Amur genes in them at least none have been reported to the public.
I don't think so. On an average bengal tiger were smaller than Amur a few decade ago But now they are the largest. I think scientist has not yet accepted that fact though
(06-18-2015, 10:19 PM)'sanjay' Wrote: I don't think so. On an average bengal tiger were smaller than Amur a few decade ago But now they are the largest. I think scientist has not yet accepted that fact though Bengals have been the same size for the past 150 years and Amurs have always been smaller than them for as long as verified weights were used, at least the measurements I have seen, even world record weights support the Bengal as being the largest cat. Were you can get tricky is this "on average" and thats because you can use Sunderban Tigers to drop their #s down but they are a separate entity than what I am talking about.  *This image is copyright of its original author  *This image is copyright of its original author
It does not make sense to add images all time here. Just mention them we all have seen images.
Do you have any proof where bengal tiger were larger than siberian tiger ? I don't think scientifically its correct statement 
In fact @sanjay, Bengal and Amur tigers are/were of the same size and weight, in old and modern records. The fluctuations in weight came from the size of the samples and the reliability of the records. Most of the statements that the Amur tigers were larger came from the reports of Baikov and another few about "giant" specimens, but now those are considered unreliable.
Modern research and the few reliable records showed that although Amur tigers do weighed more in the past, they were of the same size than the modern ones, with the exception of the Jankovski tiger at 330 cm in length. However, this is a size also reached for Bengal tigers and in this last case, we do have reliable records of tigers that have exceeded 300 kg. Finally, we can't trust in Mazák entirely, after all, like Yamaguchi said, Mazák was more guided by his heart than by the data. He used captive specimens for comparison, but those were no larger than the largest wild Bengals on record. Why he ignore those figures (like the giant tiger of Brander)? That is still beyond my understanding. Check this topic for more details: http://wildfact.com/forum/topic-who-is-t...the-tigers By the way, the Dudwa case was very old and India expended millions of dollars to keep them tigers pure and at the end, there are no longer Amur "genes" in they population. On the other hand, there is a report that suggest that Bengal tigers were introduced to Russia in the old days and that was the cause of the large size of the Amur tigers. So, there are "history" and "stories", but the evidence suggest that both populations, despite they largely different territory, reached the same body size, the same skull size and in some time, the same body weight. (06-19-2015, 05:45 AM)'sanjay' Wrote: It does not make sense to add images all time here. Just mention them we all have seen images. The reason I posted the images is because it has verified measurements from the past 130 years or more. Body length, chest girth, shoulder height and weight. Guate did a phenomonal job at providing the info to compare in a easy fashion. So to answer your question about Proof. Yes, That table is proof for me because it has so many measurements to compare and for such a long period of time. Can I ask you the same question, can you provide proof that shows amurs being larger than Bengals at any point in history? Trust me when I say that I love Amurs, I used to think they were the massive cat of legends, the 300kg averaged monsters we were always taught about. But I have been looking at body weight and measurements for a long time now, the numbers just didn't add up. If you have other measurements I haven't seen and they show the Amur being larger than the bengal, I would be extatic. The Amur is probably my Favorite Cat, so if I found something that gave them an edge over the bengal, I'd be happy with it.
That's table is not actual proof its just conclusion base on some individual.
I have lot of sources that claim Siberian are bigger 100 of blogs and expert from different source But as gaute said its matter of credibility of the source. Just like these 100 blogs and lot of expert can not of taken as 100% confirmation for Siberian bigger than bengal In same manner your proof didn't universal truth of Bengal are bigger than Siberian. Its just study which yet not verified by scientist. Though I respect Guate post, But I still think If plenty of food and favorable condition is provided Siberian can grow larger than bengal on an average (Dimension wise only). But I agree Bengal are heavier. And this is my last post in response, I don't want to Ruin the thread I have already a thread on Debate section that can be used to discuss on these tigers  (06-19-2015, 08:58 AM)'GuateGojira' Wrote: In fact @sanjay, Bengal and Amur tigers are/were of the same size and weight, in old and modern records. The fluctuations in weight came from the size of the samples and the reliability of the records. Most of the statements that the Amur tigers were larger came from the reports of Baikov and another few about "giant" specimens, but now those are considered unreliable. The presence of siberian tiger genetics may explain why bengal tigers in the north of india are longer then tigers in the south. Indian tigers in the north likely have more amur genes then the south which would probably be devoid of siberian genes. From my understanding, Amur tigers are longer then bengals generally from the tables you published, correct? (06-20-2015, 04:24 AM)'Kingtheropod' Wrote:(06-19-2015, 08:58 AM)'GuateGojira' Wrote: In fact @sanjay, Bengal and Amur tigers are/were of the same size and weight, in old and modern records. The fluctuations in weight came from the size of the samples and the reliability of the records. Most of the statements that the Amur tigers were larger came from the reports of Baikov and another few about "giant" specimens, but now those are considered unreliable. Head and body length is practically the same. Far more individuals used for bengals than Amurs, thats why you see at the smallest length and at the largest length both belong to the Bengals. More Amur individuals will bring the numbers even closer together which they already are amazingly close to begin with. No other bengals other than these two that were from a captive mother have had any Amur genitics in them, blood has been taken from numerous wild bengals and I know that I have never read anything about amur genes being found in Bengal tigers other than these two. Even the idea of "captive amurs" being larger is unfounded since there are no real measurements of Captive Bengals since all live in india.
@sanjay, those "100 books" and "experts" only repeat the same mantra without any evidence. Check what the TRUE tiger experts say about the issue:
1. “Contrary to earlier perceptions, measurements obtained from tigers captured for radiotelemetry studies in the Indian subcontinent (Sunquist 1981; Karanth, unpubl. data) show that they are not smaller than tigers captured in the Russian Far East (Dale Miquelle and John Goodrich, unpubl. data).” K. Ullas Karanth, 2003. http://www.nfwf.org/AM/Template.cfm?Sect...ENTID=8073 2. “Surprisingly, while Siberian or Amur tigers have long been thought to be the largest of the subspecies, measurements of tigers from the Russian Far East show they are currently no larger than the Bengal tigers of the Indian subcontinent [2] (D. Miquelle and J. Goodrich, unpublished data).” Melvin Sunquist, 2010. http://books.google.com.gt/books?id=XFIb...22&f=false 3. “Despite repeated claims in popular literature that members of the Amur population are the largest of all tigers, our measurements on more than fifty captured individuals suggest that their body size is similar to that of Bengal tigers”. Dale Miquelle, 2004. http://www.wcsrussia.org/DesktopModules/...attachment 4. “Siberian tigers are often considered the largest of the tiger sub-species, although they are in fact about the same size as the Bengal tiger.” WCS-Russia, 2012. http://www.wcsrussia.org/Wildlife/AmurTi...fault.aspx 5. “However, recent data on tigers captured for telemetry studies in Nagarahole (India), Chitwan (Nepal) and in Sikhote-Alin (Russia) show that tigers from these three sites are all about the same size.” K. Ullas Karanth, 2003. http://books.google.com.gt/books?id=c44r...CCsQ6AEwAA As you can see, the official confirmation is that both Bengal and Amur tigers are/were of the same size, and this is the people that have actually captured and measured tigers in the field. Mazák was an expert, yes, but his conclusions are incorrect, like I said, the largest captive Amur tigers that he mentioned measured just like the largest wild Bengal tigers recorded. The largest Manchurian skull that he measured (383 mm) is slightly smaller than the largest skull recorded by Sterndale (386 mm) and the largest skull from Nepal (381 mm) was only 2 mm shorter (McDougal, 1977). Evidence show that these two groups are of the same size and represent the maximum dimensions that a Holocene tiger can reach. Although modern Amur tigers are lighter, older ones weighed the same than the largest Bengal tigers. Interestingly, Bengal tigers have not changed too much in over 100 years, only those of the Sundarbans, which are dwarfs because of they poor habitat and prey density and size. From my conclusions, both tigers subspecies/groups measured c.190 cm in head-body, c.100 cm shoulder height and c.200 kg on average (taking in count old and modern records, including also Sundarbans specimens). In maximum figures, both reach c.220 cm in head-body (330 cm total length), c.110 cm shoulder height and a weight of c.300 kg. @Kingtheropod, in fact, I have found that there is no evidence to say that northern tigers were longer than southern tigers, that is an old idea from hunters. In fact, check that the longest tigers came from Central and Southern India, where there are records of tigers over 310 cm "between pegs". Hewett and the Maharaja of Cooch Behar presented records of tigers up to 318 cm "over curves", which means that they longest tigers were barely about 300 - 305 cm "between pegs". About the heaviest specimens, the highest figures from Hewett, Cooch Behar and the Nepalese region are between 240-260 kg, but if we search the records from Central India, we found similar figures (top of 256 kg, bottomed two scales) and although the heaviest tiger that I have found in southern India was of 227 kg "empty", peter showed that Burton weighed a tiger that bottomed a scale of 500 lb but he estimated that this male could weight up to 550 lb (250 kg). It seems that independently of the region, all mainland tigers can reach 310 cm in total length and between 240-260 kg in maximum figures. Only the Sundarbands tigers (and probably also Naga Hills, but the sample is too small) are out of these figures.
@Guate
Its always amazing to see how similar tigers are from different areas. The only areas north that I have questions about is Corbett, Kaziranga and near the Himalayas and thats based off of images and eye witnesses stating how massive they are. But I would still bet on them being very close to the same length and height as other Tigers, just maybe more robust but even that is speculative. Nice info btw
Contributing to the twist, Here is the documentary. Its long and untold story of Indian govt that kept his secret for long.
A sequel from the author of the book “TARA; THE COCKTAIL TIGRESS”, By Dr. Ram Lakhan Singh I wrote the book “TARA : THE COCKTAIL TIGRESS “ , more than a decade ago , in order to clarify the issues raised in the media, about the genetic pollution of the Indian Tiger , caused by the release of the zoo-born tigress Tara ,in the Dudhwa National Park and also about the attack on human beings in and around the forests of Dudhwa soon after her release. .It was revealed that the tigress Tara was claimed to be a gift to the Prime Minister of India Mrs. Indira Gandhi from the renowned wildlifer Dr. B. Grizimek of Germany. It was admitted that after Tara’s release in the forests, in all twenty two people got killed and fed upon by the tigress before she was shot dead by me.The Govt. Of India’s statement made in the Parliament in reply to a Question raised by Dr. Vasant kumar Pandit was also quoted to answer the question about the genetic pollution of Dudhwa tigers,“. TARA was brought to India from U.K., by Shri Arjan Singh and raised in his premises called ‘ Tiger Haven’ adjacent to Dudhwa Nnational Park and it is undisputed that it was born of parents which were not of the Indian sub-species Panthera tigris tigris.” . The need for coming out with the sequel to the book ‘TARA: THE COCKTAIL TIGRESS “ at this juncture when the friends of the Indian Tiger, all over the world, are rejoicing the news of the increased tiger population in the Tiger Reserves of India from 1706 in the year 2010 to 2226 in 2014, has arisen due to the fact that a team of the film-makers from Mumbai came down to Lucknow and informed me that they are planning to make a film, showing the need to repeat of TARA - type experiment for increasing tiger population in the forests of India . The sequel to the book clarifies why such an experiment should not be allowed in the field. The Govt. Of India’s statement made in the Parliament in reply to a Question raised by Dr. Vasant kumar Pandit was also quoted to answer the question about the genetic pollution of Dudhwa tigers,“. TARA was brought to India from U.K., by Shri Arjan Singh and raised in his premises called ‘ Tiger Haven’ adjacent to Dudhwa National Park and it is undisputed that it was born of parents which were not of the Indian sub-species Panthera tigris tigris.” |
| Users browsing this thread: |
| 3 Guest(s) |