john hawks weblog

paleoanthropology, genetics and evolution

Tuberculosis is interesting, but a lot older than 10,000 years

Mon, 2008-07-14 12:08 -- John Hawks

Hebrew University has issued a press release about ongoing research on human and animal bones from the Jericho excavations. They're looking for signs of tuberculosis:

While the origins of tuberculosis and its evolution remain unclear, it is thought it came from the first villages and small towns in the Fertile Crescent region about 9-10,000 years ago. Jericho is one of the earliest towns on earth, dating back to 9,000 B.C., and so a lot of communicable - or town - diseases would have had a good start in this community.

By examining human and animal bones from this site, the researchers will be able to see how the first people living in a crowded situation developed the diseases of crowds and how this affected the disease through changes in DNA -- of both the microbes and the people.

The most significant results of this research will come from a comparison between those data for humans and corresponding animal remains which may allow the identification of animal-human vectors and their interaction.

That's all very interesting, and looking for newly-virulent versions of tuberculosis in Neolithic bones is not a bad idea. But somebody ought to tell them that the zoonosis hypothesis (that tuberculosis was recently derived from domesticated animals like cattle) looks a lot less likely, now that ancient strains of the pathogen up to 3-million-years old have been found in living people, and signs of the disease have been found in a Middle Pleistocene human.

Anyway, that doesn't refute the idea that major changes in the pathogen population may have happened with human population growth, as new large reservoirs of people emerged. And it's quite possible that the germ went from humans to some of its animal hosts at that time, so studying the animal bones may give some information about the event. But they'll want to start with the idea of diversity within humans, not the other way around.

Neandertals

For years, I've worked on their bones. Now I'm working on their genes. Read more about the science studying these ancient people.

Denisova

From a finger bone of an ancient human came the record of a completely unexpected population. My lab is working on the science of the Denisova genome.

Acceleration

The advent of agriculture caused natural selection to speed up greatly in humans. We're uncovering some of the ways that populations have rapidly changed during the last 10,000 years.

Malapa

Just outside Johannesburg, the Malapa site is producing some of the most exciting finds in human evolution. This site is the headquarters of the Malapa Soft Tissue Project.