At 84, Ms Esau is one of the last three fluent speakers of N|uu, one of the languages spoken by South Africa's San community, also known as Bushmen. N|uu is considered the original language of southern Africa. With no other fluent speakers in the world apart from this family, the language is recognised by the UN as "critically endangered".
"We would get beaten up by the white man if we were caught speaking our language" Katrina Esau "When I was a child, I only spoke N|uu and I heard a lot of people speaking the language. Those were good times, we loved our language but that has changed," says Ms Esau in Upington, a town in the Northern Cape Province. For centuries, the San roamed this region freely, gathering plants and hunting animals to feed their families. But today the traditional practices of the San have all but died out and their descendants tell me that language is one of the only things left that connects them to their history. Inside a small wooden hut, she teaches the 112 sounds including 45 distinct clicks of N|uu with the local children. "I'm teaching the language because I don't want it to become extinct when we die," Ms Esau says. "I want to pass on as much of it as I can but I am very aware that we don't have a lot of time." Ms Esau has been running the school in her home for about 10 years.
Variation in teeth traits - protein in Neandertal, Denisovan, AMHs, archaic African populations
[DD: is this linked to saliva differences?]
Environment parameters, diet and genetic factors interact to shape tooth morphostructure. In the human lineage, archaic and modern hominins show differences in dental traits, including enamel thickness, but variability also exists among living populations. Several polymorphisms, in particular in the non-collagenous extracellular matrix proteins of the tooth hard tissues, like enamelin, are involved in dental structure variation and defects and may be associated with dental disorders or susceptibility to caries. To gain insights into the relationships between tooth protein polymorphisms and dental structural morphology and defects, we searched for non-synonymous polymorphisms in tooth proteins from Neanderthal and Denisova hominins. The objective was to identify archaic-specific missense variants that may explain the dental morphostructural variability between extinct and modern humans, and to explore their putative impact on present-day dental phenotypes. Thirteen non-collagenous extracellular matrix proteins specific to hard dental tissues have been selected, searched in the publicly available sequence databases of Neanderthal and Denisova individuals and compared with modern human genome data. A total of 16 non-synonymous polymorphisms were identified in 6 proteins (ameloblastin, amelotin, cementum protein 1, dentin matrix acidic phosphoprotein 1, enamelin and matrix Gla protein). Most of them are encoded by dentin and enamel genes located on chromosome 4, previously reported to show signs of archaic introgression within Africa. Among the variants shared with modern humans, two are ancestral (common with apes) and one is the derived enamelin major variant, T648I (rs7671281), associated with a thinner enamel and specific to the Homo lineage. All the others are specific to Neanderthals and Denisova, and are found at a very low frequency in modern Africans or East and South Asians, suggesting that they may be related to particular dental traits or disease susceptibility in these populations. This modern regional distribution of archaic dental polymorphisms may reflect persistence of archaic variants in some populations and may contribute in part to the geographic dental variations described in modern humans.
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The authors also found that all current-day Khoe-San populations admixed with migrant East African pastoralists a little over a thousand years ago. "We could not detect this widespread East African admixture previously since we did not have an un-admixed San group to use as reference. Now that we have access to ancient DNA of people who lived on the landscape before the East African migration, we are able to detect the admixture percentages in all San groups. The admixture percentages in the Khoekhoe, historically identified as pastoralists, are higher than previously estimated," says Carina Schlebusch.
Of the Iron Age individuals, three carry at least one Duffy null allele, protecting against malaria, and two have at least one sleeping-sickness-resistance variant in the APOL1 gene. The Stone Age individuals do not carry these protective alleles. "This tells us that Iron Age farmers carried these disease-resistance variants when they migrated to southern Africa," says co-first author Helena Malmström, archaeo-geneticist at Uppsala University. Read more at https://archaeologynewsnetwork.blogspot.com/2017/09/modern-humans-emerged-more-than-300000.html#yLH3TU2kB78b8vLT.99
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