Vagaries of the Genetic Record

29 June 2006

Figure by Nishahara et al. 2006

In case you missed it, a clade was born on June 19th in an online version of an article published in the June 27th issue of PNAS. The superordinal group is christened “Pegasoferae”, and true to the name it links the hand-winged (Chiroptera) bats and the odd-toed (Perrissodactyla) horses/tapirs/rhinos along with the meat-hungry Carnivora. Evidence for the revised phylogeny comes from the analysis of retrotransposons the curious wandering signifiers of genetic codes.

This marks the latest in a series of marked collisions between long-standing fossil and morphological-based mammal phylogenies and the forest of evolutionary trees offered up by the new genetics. An earlier reconfiguration involved whales, hippos and mesonychids and birthed the whale/even-toed: Cetartiodactyla. It’s another story.

Another new DNA-inspired clade is the more controversial Afrotheria, which, you’ll notice, sits at the bottom of that stack, save the backwards bagged ones.

The advent of Pegasoferae also marks the final end of the once revered order Ungulata, the hoofed-mammals. Horses and cows are now split by bats and cats.

2300 years after Aristotle, 300 years after Carolus and we’re still arguing about the arrangement of large pieces of the busty and hairy class mammalia. In fact if anything matters have become more convoluted since Linnaeus with the advent of DNA sequencing. We still navigate the murky waters by his compass now bloated into a large desktop model.

2 Responses to “Vagaries of the Genetic Record”

  1. Chelsea Says:

    What do you think it does for the taxonomy of those creatures that don’t fossilize quite as well? I have this impression that for plants, it’s made things quite more tractable (a Flava Flav-sized compass is better than none at all) but then, my pseudo-expertise in the history of plant diversification is already fading, fading….
    How do you navigate PNAS? I look at that research-methods-universe-spanning table of contents every once in a while and it just makes me woozy.

  2. rachel Says:

    the radar bell will arm or alarm when you say that!


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