[Taxacom] human-specific loss of regulatory DNA

John Grehan jgrehan at sciencebuff.org
Tue Mar 15 10:55:41 CDT 2011

Due to the kind response by several on this list I was able to read over
a recent paper in Nature on human-specific loss of regulatory DNA and
the evolution of human-specific traits. I have drafted a letter to
Nature as a bit of a long shot, and although this is less about
systematics, there may be people on this list who could give me feed
back (if there is anything so deserving) before I submit, particularly
as it involves a specialized area of developmental genetics which is a
bit of a different field to that of simple DNA sequence comparisons in
systematics. I have not included citations yet, but the draft text is
below. I am interested to know if I have made any errors of fact.




John Grehan


Human-specific loss of regularity DNA associated with the loss of penile
spines (resulting in prolonged copulation) is seen by McLean et al
(2011) to fit with an adaptive suite associated with pair bonding and
increased paternal care that also includes reduction of male canines,
moderate sized testes with low sperm motility, concealed ovulation, and
permanently enlarged mammary glands. But the absence of penile spines is
also characteristic of gorillas and orangutans which both have developed
male canines and lack human pair bonding patterns and paternal care.


Orangutans are also more like humans than African apes in having
concealed ovulation, prolonged copulation that is similar in duration to
humans, and moderate sized testes (relative to body size). These
similarities are correlated with a large suite of unique morphogenetic
similarities shared between humans and orangutans that suggest evolution
from a last common ancestor that did not include the chimpanzee and need
not, therefore, to have evolved separately within hominids because of
evolution in pair bonding and paternal care.


In view of the contrasting evidence between molecular sequence evidence
for the chimpanzee and morphogenetic evidence for the orangutans, the
evolution of human characteristics cannot be assumed to have evolved
within hominids, particularly if they are also present in orangutans.
Future work on DNA deletions such as those correlated with the loss of
penile spines may benefit from a detailed comparison to see whether
these deletions are also present in orangutans and gorillas and whether
such deletions are homologues, if that is possible where sequence
alignment is used to create homology.




Dr. John R. Grehan
Director of Science and Research
Buffalo Museum of Science
1020 Humboldt Parkway
Buffalo, NY 14211-1193

email: jgrehan at sciencebuff.org
Phone: (716) 896-5200 ext 372
Fax: (716) 897-6723


Ghost moth research

Human evolution and the great apes


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