There's a new paper out in Nature which details the genomes of several Bushmen, and how they relate to other humans, and one particular Bantu speaking individual, archbishop Desmond Tutu. It's open access, Complete Khoisan and Bantu genomes from southern Africa. I haven't read the whole thing, but it is probably best to check out Ed Yong's very thorough review first. Here's an interesting point Ed brings up:
Most surprising of all, many of their unique SNPs are actually fairly recent developments. The Bushmen are one of the oldest human groups on the planet and you might expect their genes to reflect humanity's most ancestral state. But not the SNPs - Schuster found that only 6% of !Gubi's newfound SNPs matched the equivalent sequences in the chimpanzee genome; by comparison, the same positions in the human reference genome are an 87% match for the chimp one. They can't be ancestral sequences. They must have turned up after the Bushmen dynasty diverged from other human populations, and they provide hints about the history of this most ancient of human lineages.
The paper itself uses the phrase "the oldest known lineage of modern human." It's pretty ubiquitous as a description for the Bushmen and related peoples. But as you probably know, I don't think it's that helpful, though the usage of the term "lineage" makes the topology of the phylogenetic tree clear at least. Perhaps more evidence of derived alleles in "ancient populations" will shift the definitional ground a bit....
Citation: Schuster et al., Complete Khoisan and Bantu genomes from southern Africa, doi:10.1038/nature08795
So "most divergent lineage" would be a more accurate way to phrase it?
(I fixed some typos etc.)
Quality press knew how to find the relevant angle to that story.
Associated Press, Archbishop Tutu's DNA helps show African diversity:
"We are all very, very similar to one another," Schuster said. Gibbs said the DNA differences discovered in the African subjects can't be used to support racist arguments. He noted that DNA diversity within a continent is greater than the differences between continents. The study found, in fact, that Bushmen are as different from a previously studied Yoruba man in Nigeria as a European man is.
"On average we found as many genetic differences between two Bushmen than between a European and an Asian," said Dr. Vanessa Hayes of the University of New South Wales in Australia, who worked on the study reported in Thursday's issue of the journal Nature. "This research now provides us with the tools to read the story of human evolution and specifically the story of disease evolution."Geneticists have long known that, on the level of DNA, there is no such thing as race.
As we now know, two Bushmen from the Kalahari Desert are more different from each other genetically than a European from an Asian. In other words: ethnic groups and races are smoke and mirrors by the standards of genetic research. Could there be a more wonderful reassurance in the fight against apartheid, that powder keg?
"Oldest human group" makes little sense. They are just as old as any other human group - the same amount of time has passed since all human groups last shared a common ancestor with each other, with chimps, or with any other species.
"Most divergent lineage" implies that they have evolved (diverged) more than other human lineages. No evidence of that.
Not crazy about "oldest known lineage" because again it indicates that they are somehow older, although use of the word lineage is a little closer. Really, the correct phrase would be "earliest diverging lineage."
I suppose that this looks like very nitpicky use of jargon to many non-phylogeneticists, but these incorrect descriptions of the Bushman lineage feeds directly into this all-too-commonplace expectation that their genes are going to reflect "humanity's most ancestral state," that they are somehow more primitive, etc. etc. The phylogeny says nothing of the sort.
Three of the four Bushmen are from the same group, speakers of the Northern Bush
language. The fourth is identified as a "Tuu" speaker, apparently from Gobabis. All the Bushmen I have ever met around Gobabis are also Northern Bush. Some of them identify as "!xu" (low tone), the origin I suppose of the name "!Kung", and my bet is the "Tuu" is just "!xu".
They ought to have gotten some folks from some of the other Bushman groups, whose languages have no apparent relationship at all to !Kung (or whatever we call them this year) save for the presence of clicks.
@Anon - No, not nitpicky at all. I found your explanation very helpful. Don't stop.