Duke researchers have once again made some amazing discoveries in East Africa, this time suggesting that interbreeding between quite different animals may provide survival advantages.
The setting is Tanzania’s Udzungwa National Park, absolutely one of the most beautiful wildernesses I have ever visited. More than 120 endemic mammals and 13 primate species are found here that exist nowhere else on earth. The discovery is about the most recently discovered primate, the kipunji (Rungwecebus kipunji)
There are just over 1100 kipunji left on earth, making them one of the most endangered animals creation has left us. And they all live in just 7 square miles! And very interesting, there are two separated populations: only about 100 in the Udzungwa park, and the remaining 1000 in a lower altitude area.
Yesterday a team of researchers led by Trina Roberts of the National Evolutionary Synthesis Center in Durham, N.C. (Duke) announced that while the two separated populations look identical, they have significantly different DNA.
The larger population has baboon DNA!
Note carefully. The research isn’t saying that the two species once had the same ancestor (which may be true but isn’t the point), but that modern baboon interbred with modern kipunji recently… basically since any normal evolutionary changes (through natural selection) occurred.
In fact appearances suggest the two animals if they had a common ancestor diverged a very long time ago. Baboon (Papio genus) looks more different from kipunji than chimps do from modern man. The baboon has a long flat nose not found in kipunji, and male baboons weigh up to 65 pounds. Male kipunji weigh less than half that. There are many other anatomical differences.
But at some point in the past, Papio and Rungwecebus had a tryst (that was certainly the scandal of the century up there in those xenophobic forests). The DNA analysis even tells us that Mom was Papio, and that baby Papio/Rungwecebus became the matriarch of the stronger group of kipunji. They don’t look a lot different, but DNA doesn’t lie.
“In the evolutionary history of this population there was at least one event where there was some cross-fertilization with a baboon,” said study researcher Tim Davenport of the Wildlife Conservation Society.
We know that normally when species hybridize, the offspring are almost always sterile: (mules is the common example). In East Africa we have many bird species, especially among the starlings, which hybridize and live for a single generation.
But not always. The best alter example is our own yellow-rumped warbler, which hybridizes and continues to breed so quickly field guides have a very difficult time keeping up with the new birds.
But in animals it’s extremely rare. Giraffe are probably the best exception, as evidenced in zoos where interbreeding in earlier years caused serious embarrassment to zoo directors. Look carefully in backwoods’ zoos and you might find a rather unusual looking giraffe.
But now the Duke researchers are suggesting there might be a reason for all of this.
The population which is strongest of the two kipunji is the one with baboon DNA. Baboon are a very successful primate in the evolving modern world dominated by a single all-powerful primate known as man. Many tree dwelling monkeys aren’t. Is the larger kipunji population, larger, because it got something, or learned something from being hard wired to a more successful cousin?
This would introduce a new evolutionary mechanism that works a bit faster than waiting for gamma rays to move chromosomes around in some useful way. It’s really quite exciting research. And it probably correlates in some way to current research into whether modern man interbred with Neanderthals before sending them into extinction.
Kipunji was discovered in the Udzungwa in 2003, the twelfth new primate to be discovered in this forest during my life time, but the only completely new primate species discovered in the world since 1923!
Udzungwa National Park is only 785 sq. miles, but that’s because it sits in rugged forests that still remain unpopulated and not yet deforested that – well – don’t require protection… Yet. The overall huge area of pristine marvels is almost 4,000 sq. miles.
It’s not easy to visit. My few visits have hardly touched the edges of this massive forest. I tend to think that Tanzanian authorities are following the unofficial advice from WCS and the World Wildlife Fund not to develop the park. There are more tourists that visit Mikumi National Park every week (a half hour away) than all the kipunji in existence!