Tim Crowe
UNTIL recently, the ancient origins, anatomical, linguistic and genetic distinctiveness of southern African San and Khoikhoi people were matters of confusion and debate.
They are variously described as the world’s first or oldest people; Africa’s first or oldest people, or [the first people of South Africa] (http://www.news24.com/South Africa/News/Khoi-San-want-recognition-as-first-people-of-SA-20150820).
What they are, in fact, are two evolutionarily related, but culturally distinct, groups of populations that have occupied southern Africa for up to 140 000 years.
Their first-people status is due to the fact that they commonly retain genetic elements of the most ancient Homo sapiens. This conclusion is based on evidence from specific types of DNA.
This evidence also demonstrates that other sub-Saharan human populations retain genetic bits and pieces of DNA from non-KhoiSan primordial humans that pre-date their Out of Africa colonisation of the balance of the world.
What is important in the debate on the origins, and diversity among population groups, of Homo sapiens is to establish what cannot, and should not, be derived from the various DNA evidence used to support the KhoiSan-as-first-people hypothesis.
This is that the KhoiSan, or any other groups of populations of humans, can be assigned to evolutionarily meaningful “races” – or sub-species in biological classification.
The abovementioned DNA evidence, if interpreted incorrectly, could be used to support the findings of the “scientific” racial anthropologist [Carleton S. Coon] (http://www.encyclopedia.com/topic/Carleton_Stevens_Coon.aspx).
As recently as 1962, Coon recognised the KhoiSan as the Capoid race, based on the distinctive anatomical features of the Capoids from those he used to designate the Congoid race.
These include golden brown rather than sepia coloured skin, the presence of epicanthic eye folds and prominent cheekbones and steatopygia.
Indeed, the scientifically correctly interpreted evidence points quite to the contrary.
lHuman evolution can be mapped like a network, not drawn like a tree.
If one were to compare the entire DNA genomes from representatively sampled human populations from around the world, the resulting relationships would look more like an evolutionarily reticulated chain-link fence. In other words, a network rather than a tree. This even applies to even purportedly racially important anatomical features.
This is because human population groups worldwide are highly homogeneous (99.5 percent similar) genetically and their anatomical features vary in an uncorrelated fashion over the landscape.
In fact, these groups are, in evolutionary terms, very recent entities that have no biological or [taxonomic] (https://theconversation. com/how-science-has-been-abused-through-the-ages-to-promote-racism-50629) significance.
The DNA evidence used to discover the human genetic “footprints” that characterise the KhoiSan, and other diverging populations, is the same that forensic pathologists use to determine an unidentifiable corpse’s population group. This process has been popularised on television shows like [(CSI)] (http://www.tvmuse.com/ tv-shows/CSI-Crime-Scene- Investigation_8779/) and [Bones] (http://www.fox.com/bones).
This DNA evidence comes from:
lY chromosome polymorphisms inherited without recombination along [male lineages] (http://www.ramsdale.org/dna13. htm).
lSingle nucleotide polymorphisms, or SNPs, from nuclear [DNA](http://www.nature.com/nature/journal/v409/n6822/full/409821a0.html), and
lMost especially from [mitochondrial DNA] (http://mbe. oxfordjournals.org/content/24/3/757.full.pdf+html).
Mitochondria are organelles within a cell that have their own independent DNA, separate from that in the nucleus that determines an organism’s external appearance, physiology, etc. They are involved with cellular respiration and nothing more.
Like the abovementioned polymorphisms, mitochondrial DNA (and especially a component of it called the D-loop) evolves much faster than the bulk of nuclear DNA.
Moreover, mitochondrial DNA is inherited maternally (since offspring get their mitochondria from their mother’s egg) and is thus not intermixed with paternal DNA during reproduction.
This allows the detection of direct, genetically “ungarbled”, connections among evolutionarily recently evolved human population groups.
The mistake some evolutionary genetic anthropologists make is that they ignore the overwhelming balance of evidence that there is no evolutionarily significant racial variation in either genes or anatomy [see “How science has been abused through the ages to promote racism” – The Conversation – November 20, 2015]. Instead, they focus on these very few bits-and-pieces of DNA that change rapidly (in evolutionary terms). This way they reach distorted conclusions about discernible “races” within the human species.
lWhy there is only one race: the human race
Recent DNA results used to detect human population genetic “footprints” are summarised in [Humanity’s forgotten return to Africa revealed in DNA] (https://www.newscientist.com/article/dn24988-humanitys-forgotten-return-to-africa-revealed-in-dna/).
The story it tells is as follows: About 140 000 years ago human populations from East and/or Central Africa moved southwards and “colonised” western southern Africa. The probable nearest living relatives of these source populations are the [Hadzabe people] (http://ngm.nationalgeographic. com/2009/12/hadza/finkel-text) from north-central Tanzania and and [Mbuti pygmies ](http://ngm.nationalgeographic.com/ngm/0509/feature5/) from the eastern Congo.
This migration gave rise to the present-day [San hunter-gatherers] (http://www.san.org.za/history. php).
Much more recently – about 2 000 years ago – there was a second movement of “colonists” from the north into south-western Africa that gave rise to the pastoral [Khoikhoi people] (http://www. sahistory.org.za/people-south-africa/khoikhoi).
This second group of “settlers” carried within its genome bits of Eurasian-sourced – and even some [Neanderthal] (http://humanorigins.si.edu/evidence/human-fossils/species/homo-neanderthalensis) – DNA derived from European humans that had returned to Africa about 3 000 years ago.
Subsequent to this second colonisation, there was intermixing between the Khoikhoi and San (giving rise to their close anatomical similarities), despite the fact that they retained their marked cultural and linguistic differences.
Much more recently – about 1 700 years ago – there was a third major north-to-south migration, this time by Bantu-speaking, black Africans into south-eastern Africa.
Those “settlers” that eventually became the Xhosa peoples moved westwards and encountered the Khoikhoi, whom they drove further west and intermixed with genetically. So, yes it is now possible for genetic evolutionary “anthropologists” to distinguish population differences among humans to infer the timing of their movements throughout the globe.
It is even possible to map one’s genetic “ancestry”, as Nelson Mandela did, indicating that he possessed some [KhoiSan DNA] (http: //www.iol.co.za/news/south-africa/dna-test-may-reveal-youre-related-to-madiba-1.268615).
The important point is that this evidence should not be used to assert that these differences (or shared bits of “ancient” DNA) support the identification of multiple human “races”. In fact, it confirms the assertion by the late founder of the Pan Africanist Congress of Azania [Robert Sobukwe] (http://www.sa history.org.za /archive/robert-sobukwe-inaugural-speech-april-1959), who wisely concluded that there is only one race: the human race.
l Crowe served as an academic in the Department of Biological Sciences at UCT for 40 years, retiring in 2013, and was elected a Lifetime Fellow at UCT