DNA news stories: bird and mammal evolution

[bh480@scn.org]

From: Ben Creisler bh480@scn.org

DNA news stories: bird and mammal evolution

A couple of recent news stories concerning evolution and
DNA studies fall a bit outside the topic of dinosaurs
strictly speaking but I think they are worth mentioning:

DNA yields aquatic bird evolution surprise: flamingo and
grebe are close relatives
http://www.science.psu.edu/alert/Hedges7-2001.htm

If this research holds up, it points out one of the main
problems with cladistic analyses based solely
on "characters" derived from skeletons -- apparent
similarities or dramatic differences in body structure may
be misleading in terms of true evolutionary histories. The
many birdlike theropods or theropod-like birds that have
been turning up lately provide an obvious case in point.
Unfortunately without access to ancient DNA, the real
story may remain unresolved.

(Don't have the citation or abstract for the paper yet.)

Mammal evolution theories confirmed and debunked:
An article from Popular  Mechanics can be seen at:
http://c.moreover.com/click/here.pl?l21352978

The official abstract can be viewed at:
http://link.springer.de/link/service/journals/00335/bibs/10
12007/10120513.html

Killian, J. Keith , Thomas R. Buckley, Niall Stewart,
Barry L. Munday, Randy L. Jirtle, 2001.
Marsupials and Eutherians reunited: genetic evidence for
the Theria hypothesis of mammalian evolution. Mammalian
Genome. 12(7): 513-517

Abstract
The three living monophyletic divisions of Class Mammalia
are the Prototheria (monotremes), Metatheria (marsupials),
and Eutheria (`placental' mammals). Determining the sister
relationships among these three groups is the most
fundamental question in mammalian evolution. Phylogenetic
comparison of these mammals by either anatomy or
mitochondrial DNA has resulted in two conflicting
hypotheses, Theria and Marsupionta, and has fueled a
``genes versus morphology'' controversy. We have cloned
and analyzed a large nuclear gene, the mannose 6-
phosphate/insulin-like growth factor II receptor
(M6P/IGF2R), from representatives of all three mammalian
groups, including platypus, echidna, opossum, wallaby,
hedgehog, mouse, rat, rabbit, cow, pig, bat, tree shrew,
colugo, ringtail lemur, and human. Statistical analysis of
this nuclear gene unambiguously supports the morphology-
based Theria hypothesis that excludes monotremes from a
clade of marsupials and eutherians. The M6P/IGF2R was also
able to resolve the finer structure of the eutherian
mammalian family tree. In particular, our analyses support
sister group relationships between lagomorphs and rodents,
and between the primates and Dermoptera. Statistical
support for the grouping of the hedgehog with Feruungulata
and Chiroptera was also strong.