Example of an ecotype

By Razib Khan | November 16, 2006 11:34 am

polar.jpgFrom here: “Cronin et al. (1991) then discovered that mtDNA of brown bears is paraphyletic with respect to polar bears. That is, the mtDNA of brown bears of the Alexander Archipelago in southeastern Alaska is more closely related to the mtDNA of polar bears than it is to the mtDNA of other brown bears. Cronin et al. (1991) reported that mtDNA sequence divergence between Alexander Archipelago brown bears and polar bears is only about 1%, whereas a divergence of about 2.6% separates polar bears from brown bears occurring elsewhere…Following the discovery of Cronin et al. (1991), others corroborated the finding of paraphyletic mtDNA in brown bears and polar bears. Talbot and Shields (1996a, 1996b) suggested that the Alexander Archipelago brown bears represent descendents of ancestral stock that gave rise to polar bears.”
Caution!!! Caution!!! Appropriate consideration given to the overuse of mtDNA in phylogeography, etc. The idea is that marker phylogeny has in general reflected our gestalt perception of taxonomical relationships, but there’s a reason that people test the hypotheses.

  • http://scienceblogs.com/evolgen RPM

    Making demographic inference from a single locus? Nothing could go wrong there. This isn’t so much a hypothesis as a first step in sampling multiple independent loci.

  • http://www.idiocentrism.com John Emerson

    In linguistics you have something called “areal effects” (not sure the term is quite right).
    The fundamental of linguistic analysis is language family. E.G., Finnish and Hungarian can be shown to be in the same family for structural reasons, even though they sound different, have a different vocabulary, etc., etc.
    Vocabulary borrowing confuses the issue. Hungarian has a lot of Russian and German and Rumanian, Finnish has Russian and Swedish. Japanese has a lot of Chinese.
    Areal effects are borrowed non-vocabulary items. For example, some think that languages neighboring Chinese developed tonal features they didn’t originally have. Rumanian, Hungarian, and Bulgarian come from distant familes, but have converged in certain respects. The areal effects I know of are mostly phonetic, but I think that grammatical structures are also borrowed. (The Singlish of Singapore brings Chinese grammar into English).
    This is just a comparison and may not be relevant — but I think that there’s a tendency to say that superficial things are borrowed (vocabulary), but not deep things (grammar, phonetics) — whereas areal effects are deep things which are borrowed.

  • http://www.shan.ca.tf Shan

    Nice ‘analogy’, John. :)


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About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com


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