Tigers again...
Tigers have been decimated by hunting and for the market, such as for medicinals. They have also lost habitat. Here (right) is habitat destruction shown in satellite photos from 1932-1980 and in the mid-1980's of the forests in Sumatra.
This is what Sumatra looks like today near one of the major national parks for tigers. The forest has been cut down for various kinds of production. These are harvested oil palm nuts. Forest has also been cut down for rubber plantations.
What I did is sequence one of the mitochondrial genes, cytochrome b, using blood as a source of DNA, in our molecular lab. What we found was that the Sumatran tiger is genetically distinct, or diagnosably distinct, from all the mainland forms and none of the mainland tigers are distinct from one another. As you know, DNA has 4 nucleotides or bases, GATC. Here's a character A (site 186) found only in the Sumatrans. Another site (706) has a G only in Sumatrans. And here's another A (site 957) that characterizes Sumatrans.
And when we look at their phylogenetic relationship, the Sumatrans come out toether because of those characteristics, whereas all the other tigers are mixed together. No differentiation at all. So we conclude there are two kinds of tigers.
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