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[Josh Greenman <josh.greenman AT gmail.com>]

http://www.scienceblog.com/cms/africas-rarest-monkey-had-intriguing-sexual-past-dna-study-confirms-27137.html

Africa's rarest monkey had an intriguing sexual past, DNA study confirms

Durham, NC -- The most extensive DNA study to-date of Africa's rarest
monkey reveals that the species had an intriguing sexual past. Of the
last two remaining populations of the recently discovered kipunji, one
population shows evidence of past mating with baboons while the other
does not, says a new study in Biology Letters. The results may help to
set conservation priorities for this critically endangered species,
researchers say.

A shy tree-dwelling monkey with a black face and long brown fur, the
kipunji (key-POON-jee) was unknown to science until 2003, when it was
discovered in a remote region of southern Tanzania. Until recently,
little was known about its biology except what scientists could glean
from observations and a single specimen found in a farmer's trap. The
first analyses revealed that kipunji represented an entirely new genus
of primate, Rungwecebus. Now, thanks to additional DNA samples
collected from dung and tissue -- the most extensive genetic data to
date -- scientists have a more complete picture of the genetic makeup
of this monkey.

The kipunji is found in two tiny forest fragments totaling less than 7
square miles, researchers explained. Of the last two remaining
populations, one is in Tanzania's Southern Highlands, and the other
lies 250 miles away in a mountain range called the Udzungwas. Armed
with six dung samples from the Udzungwas -- the first ever genetic
material from this population -- and two additional tissue samples
from the Southern Highlands, the researchers were able to reconstruct
the genetic relationships between these populations and kipunji's
closest kin.

Confirming other reports, the Southern Highlands population contained
bits of DNA that are similar to baboons. This suggests that the two
species interbred at some point after they diverged, researchers
explained. "Way back in time in the evolutionary history of this
population there was at least one event where there was some
cross-fertilization with a baboon," said study author Tim Davenport of
the Wildlife Conservation Society.

In contrast, the researchers discovered that the Udzungwa population
showed no traces of baboon DNA. "We thought the DNA from the second
population would match the first one, but instead we got something
quite different," said first author Trina Roberts of the National
Evolutionary Synthesis Center in Durham, NC.

Mating across the species barrier isn't unheard of in the animal
kingdom. "We usually think of species' genomes as being contained and
not sharing with each other, but sometimes one species picks up
genetic material from another through interbreeding," said Roberts.
"It's as if the genomes are a little leaky."

The findings help to settle a debate over kipunji's status as a new
genus of primate. "They're still separate taxa -- they're not baboons,
they're still kipunji," said co-author Bill Stanley of the Field
Museum of Natural History in Chicago. "But there's a little bit of
baboon DNA that shows up when you analyze their DNA."

Their results may also help to set conservation priorities for this
critically endangered monkey. Much of the kipunji's remaining habitat
is threatened by deforestation for farming and other uses, the
researchers explained. "There's a lot of pressure on the forest for
natural resources ? food, medicine, fuel, and building materials,"
said Davenport. "Part of the challenge we have is making sure the
forest isn't degraded any further."

Census data indicate there are just over 1,100 individuals left in the
wild, said Davenport. Of these, roughly 1,000 live in the Southern
Highlands, and 100 remain in the Udzungwas. Both populations may
require habitat protection if we are to preserve the genetic diversity
of the species, researchers said.

"Udzungwa is a tiny population," said Roberts. "What we've shown is
that it is substantially different from the first population. We may
not be able to resurrect it by simply transplanting kipunji from one
population to the other," Roberts said.

"If we were to lose it we might in fact lose the true kipunji genome
forever," she added.

"Does the baboon DNA help to explain why there are differences in
number between the two populations, or is just a remnant of
evolutionary history?" asked Davenport. "It's too early to say, but
it's something we're looking at."

"We have two separate populations that are slightly genetically
different, so until we learn more it is extremely important that we
maintain both of them," Davenport said. "It might be that those
genetic differences have an impact on their survival in the future."

Additional authors on the study include Kyndall Hildebrandt, Trevor
Jones, Eric Sargis, and Link Olson.

The team's findings appear online in the November 11th issue of Biology 
Letters.

CITATION: Roberts, T. E., T. Davenport, et al. (2009). "The
biogeography of introgression in the critically endangered African
monkey Rungwecebus kipunji." Biology Letters.

The Wildlife Conservation Society saves wildlife and wild places
worldwide. We do so through science, global conservation, education and
the management of the world's largest system of urban wildlife parks,
led by the flagship Bronx Zoo. Together these activities change
attitudes towards nature and help people imagine wildlife and humans
living in harmony. WCS is committed to this mission because it is
essential to the integrity of life on Earth. Visit: www.wcs.org

The National Evolutionary Synthesis Center (NESCent) is an NSF-funded
collaborative research center operated by Duke University, the
University of North Carolina at Chapel Hill, and North Carolina State
University.