Karela Fry

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The tiger’s genome

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The first whole-genome study of tigers has just been reported in an article entitled “The tiger genome and comparative analysis with lion and snow leopard genomes”. The article in Nature has a wonderful summary of the natural history of the tiger:

The tiger (Panthera tigris), the largest felid species on Earth and a widely recognized symbol for wildlife conservation, is one of the world’s most endangered species. Tigers are a keystone species and natural indicators of the health of the ecological communities in which they are found. The current estimates of wild tigers range from just 3,050 to 3,950 individuals. It is postulated that without conservation measures tigers will soon become extinct in the wild, thus turning the preservation of existing wild tiger populations into a major goal of conservation efforts. Tigers comprise of nine genetically validated subspecies. Four of these went extinct in the wild during the last century (Javan, Balinese, South China and Caspian tigers), leaving five extant subspecies (Amur, Bengal, Indochinese, Malayan and Sumatran tigers). The Amur tiger (Panthera tigris altaica) is the largest in overall size and the only subspecies inhabiting snow-covered regions.

Relationship of the tiger to other mammalian species. The Venn diagram shows the number of unique and shared gene families among seven mammalian. The time lines in the evolutionary tree indicate divergence times among the species.

The main results:

The tiger genome is particularly enriched in olfactory receptor activity … In most cats, smell has an important role in social behaviour such as territory ownership and mating, while vision and hearing are important for hunting. … Metabolism pathways associated with protein and fatty acid, which are important sources of energy, were enriched with genes having Panthera-specific functional changes … These signals of amino-acid metabolism have been associated with an obligatory carnivorous diet … Functional categories for positively selected genes were over-represented in muscle filament sliding … [Significant] evidence of rapid evolution in the tiger for muscle strength (muscle contraction and actin cytoskeleton), energy metabolism (GTPase activity, ATP binding and energy reserve metabolic process), and sensory nerves (G-protein coupled receptor activity, olfactory receptor activity, visual perception and nervous system development).

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Written by Arhopala Bazaloides

September 18, 2013 at 10:07 am

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