Friday, May 7, 2010

Sequencing the Neandertal Genome

I didn't know that our heavily browed relative, the Neandertal, was named so because the first partial skull was found in a cave in Neander Tal (Neander Valley - Tal is German for Valley) in western Germany, east of Dusseldorf. I just imagined the name had some Latin significance. - silly me.

A new article published on, the web counterpart to Science Magazine, shows that a long list of scientists have had a hand in the building a draft (unfinished) sequence of the Neandertal genome - neat let's grow one in a big jar. The cure for male pattern baldness is only a petri dish away...

Also, noted in an article by Carl Zimmer, Skull Caps and Genomes, and one of the most interesting facts brought to light so far is that "Today, the people of Europe and Asia have genomes that are 1 to 4 percent Neanderthal." Signs of likely interbreeding (gene flow) less than 100,000 years ago - blagh.

In the Sciencemag article, population divergence, the point in time when modern humans and Neandertals diverged as separate species, is discussed. It is currently accepted to have happened between 270,000 and 440,000 years ago.

Imagine a bar full of different species of human relatives. A pretty, nearly modern, human woman sits sipping her third wild berry martini all alone, when a Neandertal male, previously split from her group over a quarter million years ago, approaches and compliments her on her small, smooth forehead and excellent posture. She giggles and thinks, why not?

However, the post-divergence interbreeding is not the only possible answer - thankfully. In the Sciencemag article, four possible scenarios have been identified to account for the 1 to 4 percent of Neandertal genetic content of Europeans and Asians. Of the four choices:

  1. Gene flow into Neandertals from other pre-existing hominins - they refer to the collection as Homo erectus
  2. Gene flow (possibly back and forth) from late Neandertals to early modern humans, Homo sapien
  3. Neandertal gene flow between the ancestors of all non-Africans (meaning Europeans, Asians, etc.) that happened after they left Africa
  4. Neandertals co-existed with the ancestors of the European, Asian, and others and the gene flow happened before they left Africa 
Methods 3 & 4 seem to fit the data, but the group seems to think that scenario 3 is the most likely. So it does seem that after the group of beings destined to populate most of Europe and Asia arrived, they had a little Neandertal slipped into their gene pool. Where was the lifeguard on duty that day? 

For the most part, I feel okay about it. Although it could explain why I furrow my brows and make grunting noises when I'm frustrated, and my predilection for games where the object is to hit something with a stick. 

And, I still think Captain Cavemen and the Teen Angels was one of the best Hanna Barbara cartoons ever made. Hey, that's the perfect analogy for Neandertal gene flow into modern humans. A cave man traveling around with three attractive, obviously Homo sapien, women in a van. We all know that vans are love machines on wheels...

No one ever said that being human wasn't gross. After all of the approximately 100 trillion human cells that comprise the body of the average person, we are host to 10 to 20 times that amount of others. The others are bacteria, fungus, and other creepy crawlies - but that a topic for another post.

A note about the spelling of Neandertal vs. Neanderthal. Zimmer used Neanderthal throughout his article and the Sciencemag article used Neandertal.  It seems that most sciencey people use Neandertal now - a return to the original German spelling and pronunciation. Two good discussions of the nomenclature at Talk Origins and at John Hawks blog who also has a great post on the new Neandertal Genome news. However, in Neandertal Germany there is a Neanderthal Museum - go figure...