Species diversity

“Species diversity” can be read two ways: diversity within a species or diversity between species. The great DNA Barcoding project is finding both.

Paul Herbert, a scientist in Guelph, Ontario, is working on a project for analyzing the DNA of every species. Everything except bacteria has mitochondria to produce energy. Mitochondria use cytochrome C in their energy cycles. Cytochrome c oxidase is an enzyme that helps along one step in the energy cycle. (Just to let you know how important enzymes are to your body, many vitamins are substances that are needed to make enzymes. Anyway, just about every animal or plant has some version of it. Biological enzymes are mostly made of protein, which means that they are coded for by genes. So the DNA analysis focuses on the gene for subunit 1 of cytochrome c oxidase, which is called CO1.

For the barcode of the animal kingdom, the researchers selected a segment of the mitochondrial cytochromec oxidase subunit 1 (COI) gene.

They analyzed birds of North America and bats of Guyana.

For the bats, they analyzed 840 specimens representing 87 species. (One-fifth of mammals are bats.) Most of them, 81 species, were consistent in their DNA. But six species showed deep splits between populations. They are either separate species that still look similar or species in the making. Members of each group avoid breeding with the other.

small wading birds like sandpipers
For the birds, they were able to get over 2500 specimens for 643 or the 690 known species, or 93%. Some unsuspected species were discovered. And some that appeared to be separate species were the virtually same in their DNA. (I suspect that the same analysis would put us in the same species as chimpanzees.)

In 95% of the birds, the DNA analysis agrees with established taxonomy and gives the same answer. The researchers add:

The few cases where barcodes failed to separate bird species involved either closely allied allopatric taxa whose status as distinct species is uncertain or sister taxa that hybridize (Kerr et al., in press).

Once again, two lines of evidence both support common descent.

Follow the link for more, including links to the scientific papers, or vist “Birds, Bats, and DNA Barcodes” for a nice summary of the species results.


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