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Home / Science / A genome-wide study confirms that there are six Tiger subspecies

A genome-wide study confirms that there are six Tiger subspecies



  • According to a study published today in the journal Current Biology, uncertainty about how many Tiger subspecies there are in the world has undone efforts to conserve what is left of the global tiger population.
  • A research team led by Yue-Chen Liu of China's Peking University analyzed the complete genome of 32 Tiger specimens selected representative of all six possible subspecies to confirm that Tiger was actually grouped into six genetically distinct groups fall.
  • The researchers also used their genome-wide investigation to find evidence that different groups of tigers have adapted to the different environments in their geographic regions through the process of natural selection. They say that their genomic research shows that there was very little gene flow between tiger populations, but also that each subspecies has a unique evolutionary history despite the small genetic diversity of the big cat. Www.mjfriendship.de/de/index.php?op…=view&id=1
    67 A century ago, scientists claimed that there are fewer than 4,000 people today, and fewer than 4,000 than 10 percent of their historical range. The 13 Tiger countries responded to this steep decline in 2010 with an ambitious plan to double the world population of endangered cats by 2022, and Nepal in particular has successfully reversed the tiger's decline.

    To save species from extinction, however, it helps to understand this species as much as possible. Nevertheless, there are discussions in science about whether there are two subspecies of Panthera tigris as suggested by some morphological and ecological analyzes, or five or six subspecies for which there are molecular genetic evidence [19659005]according to a study published today in the journal Current Biology, this uncertainty about such a fundamental feature of the species has nullified the efforts to preserve what is left of the tiger population of the world. "The lack of consensus on the number of tiger subspecies has hindered global efforts to recover endangered species, as both offspring and landscape intervention of wild populations increasingly require an explicit demarcation of conservation management units," said the authors of the study , a research team led by Yue-Chen Liu from Peking University in Beijing, write

    Liu and his team analyzed the complete genome of 32 Tiger specimens that are representative of all sorts of subspecies to confirm that Tiger actually do this divided into six genetically distinct groups.

    "This study is the first to reveal the natural history of the tiger from a genomic perspective," said co-author Shu-Jin Luo of Beijing University in a statement. "It provides robust, genome-wide evidence for the genesis and evolution of this charismatic megafauna species."

    The six subspecies that have been confirmed by research are the Amur or the Siberian Tiger ( Panthera tigris altaica ) Eastern Siberia and Northeast China; the Bengal Tiger ( Panthera tigris tigris ) in Bangladesh, Bhutan, India and Nepal; the southern Chinese tiger ( Panthera tigris amoyensis ), which is believed to have died out in the wild; the Sumatran tiger ( Panthera tigris sumatrae ), the last of the tiger populations of the Indonesian island, itself endangered; the Indo-Chinese tiger ( Panthera tigris corbetti ), which occurs in Myanmar, Thailand and Laos but has not been registered in Vietnam for more than two decades; and the Malayan tiger ( Panthera tigris jacksoni ), first recognized in 2004 and also threatened with extinction.

    This map shows postulated propagation paths and broadening extents of modern tigers. Credit: Liu et al. (2018). doi: 10.1016 / j.cub.2018.09.019

    The research also confirmed that there were already three other Tiger subspecies that were already extinct: the Javantiger ( Panthera tigris sondaica ), the Bali Tiger (19459006) Panthera tigris balica ), and the Caspian Tiger (19459006) Panthera tigris virgata [194559005] All six surviving subspecies date back to a common ancestor 110,000 years ago, the researchers concluded. "Within the Asian mainland, the Bengal tigers formed the earliest divergence, while the Amur tigers formed the last," they write in the study. "The Indochinese Tiger is the sister taxa of the Malay Tiger, indicating a new, albeit substantial differentiation."

    The researchers used their genome-wide investigation to look for evidence that different groups of tigers have adapted to the different living conditions of their geographical regions through the process of natural selection. They say that their genomic research shows that there was very little gene flow between tiger populations, but also that each subspecies has a unique evolutionary history despite the small genetic diversity of the big cat.

    "We were quite astonished in the end" By performing a step-by-step genome-wide scan, seven regions with 14 genes stood out as potential regions that could be selected, "said Luo.

    Of course, there are some differences between Tiger subspecies Amur tigers, for example, are large and have pale orange fur and brownish streaks, while Sumatran tigers are smaller and have dark fur with thick black streaks.The researchers found the strongest signal of natural selection in the Sumatra Tiger. Tiger and his ADH7 gene related to body size, Liu and his team theorize that the Sumatran tiger, which is different from all continental tiger subspecies, adapted its smaller size to reduce its energy requirements and survive on the smaller ones Loot to the Sunda Island, such as boars and a small deer the muntjac.

    These discoveries provide strong genetic evidence for subspecies delimitation in the tigers, Luo said, "Tigers are not all the same, tigers from Russia are evolutionarily different from those from India, even tigers from Malaysia and Indonesia are different."

    The findings may also help inform the management and planning of tiger conservation, the authors write. "As with many endangered species, tigers have been classified into subspecies – natural geographically separate populations – for the purpose of detection and conservation … as are many of the tiger conservation strategies and policies, including coordinated breeding programs and laws in several tiger states , based on the "subspecies taxonomy", an adequate description of the subspecies is crucial. "

    The results of their genome-wide study" correspond exactly with the previously mentioned geographical subspecies, "the researchers added. "Understanding the natural history of the tiger from a genomic perspective provides a data-driven basis for subtype detection, strategic planning, and management measures." Our overall goals are to reduce species by maximizing efforts to conserve genetic diversity, evolutionary uniqueness and the potential of the species Panthera tigris. "

    Malayan tiger. Photo by Rhett Butler.

    CITATIONS

    Goodrich, J., Lynam, A., Miquelle, D., Wibisono, H., Kawanishi, K., Pattanavibool, A., Htun, S., Tempa , T., Karki, J., Jhala, Y. & Karanth, U. 2015. Panthera Tigris. The Red List of Endangered Species of the IUCN 2015: e.T15955A50659951. doi: 10.2305 / IUCN.UK.2015-2.RLTS.T15955A50659951.de. Downloaded October 25, 2018.

    • Liu et al. (2018). Genome-wide evolutionary analysis of natural history and adaptation in the tigers of the world. Current Biology 28, 1-10. doi: 10.1016 / j.cub.2018.09.019


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