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Genetic history of Central Africa

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The genetic history of Central Africa encompasses the genetic history of the people of Central Africa. The Sahara served as a trans-regional passageway and place of dwelling for people in Africa during various humid phases[1][2][3] and periods throughout the history of Africa.[4][5]

Archaic Human DNA

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Further information: Interbreeding between archaic and modern humans § Archaic African hominins

Archaic traits found in human fossils of West Africa (e.g., Iho Eleru fossils, which dates to 13,000 BP) and Central Africa (e.g., Ishango fossils, which dates between 25,000 BP and 20,000 BP) may have developed as a result of admixture between archaic humans and modern humans or may be evidence of late-persisting early modern humans.[6] While Denisovan and Neanderthal ancestry in non-Africans outside of Africa are more certain, archaic human ancestry in Africans is less certain and is too early to be established with certainty.[6]

Ancient DNA

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In 4000 BP (or even earlier during the Mesolithic), there may have been a population that traversed from Africa (e.g., West Africa or West-Central Africa), through the Strait of Gibraltar, into the Iberian Peninsula, where admixing between Africans and Iberians (e.g., of northern Portugal, of southern Spain) occurred. Based on a small trace presence of sub-Saharan African components in select samples from Iberia, and the discovery of a mitogenome L2a1 found in one individual, while all others belonged to European mitochondrial haplogroups.[7]

Cameroon

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West African hunter-gatherers, in the region of western Central Africa (e.g., Shum Laka, Cameroon), particularly between 8000 BP and 3000 BP, were found to be related to modern Central African hunter-gatherers (e.g., Baka, Bakola, Biaka, Bedzan).[8]

Democratic Republic of Congo

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At Kindoki, in the Democratic Republic of Congo, there were three individuals, dated to the protohistoric period (230 BP, 150 BP, 230 BP); one carried haplogroups E1b1a1a1d1a2 (E-CTS99, E-CTS99) and L1c3a1b, another carried haplogroup E (E-M96, E-PF1620), and the last carried haplogroups R1b1 (R-P25 1, R-M415) and L0a1b1a1.[9][10]

At Ngongo Mbata, in the Democratic Republic of Congo, an individual, dated to the protohistoric period (220 BP), carried haplogroup L1c3a.[9][10]

At Matangai Turu Northwest, in the Democratic Republic of Congo, an individual, dated to the Iron Age (750 BP), carried an undetermined haplogroup(s).[9][10]

Y-Chromosomal DNA

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Further information: Y-DNA haplogroups in populations of Sub-Saharan Africa

Haplogroup R-V88 may have originated in western Central Africa (e.g., Equatorial Guinea), and, in the middle of the Holocene, arrived in North Africa through population migration.[11]

Mitochondrial DNA

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Further information: Haplogroup L1 (mtDNA) and Haplogroup L2 (mtDNA)

In 150,000 BP, Africans (e.g., Central Africans, East Africans) bearing haplogroup L1 diverged.[12] Between 75,000 BP and 60,000 BP, Africans bearing haplogroup L3 emerged in East Africa and eventually migrated into and became present in modern West Africans, Central Africans, and non-Africans.[12] Amid the Holocene, including the Holocene Climate Optimum in 8000 BP, Africans bearing haplogroup L2 spread within West Africa and Africans bearing haplogroup L3 spread within East Africa.[12] As the largest migration since the Out of Africa migration, migration from Sub-Saharan Africa toward the North Africa occurred, by West Africans, Central Africans, and East Africans, resulting in migrations into Europe and Asia; consequently, Sub-Saharan African mitochondrial DNA was introduced into Europe and Asia.[12]

Mitochondrial haplogroup L1c is strongly associated with pygmies, especially with Bambenga groups.[13] L1c prevalence was variously reported as: 100% in Ba-Kola, 97% in Aka (Ba-Benzélé), and 77% in Biaka,[14] 100% of the Bedzan (Tikar), 97% and 100% in the Baka people of Gabon and Cameroon, respectively,[15] 97% in Bakoya (97%), and 82% in Ba-Bongo.[13] Mitochondrial haplogroups L2a and L0a are prevalent among the Bambuti.[13][16]

Autosomal DNA

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Genetically, African pygmies have some key differences between them and Bantu peoples.[17][18]

Medical DNA

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Evidence suggests that, when compared to other Sub-Saharan African populations, African pygmy populations display unusually low levels of expression of the genes encoding for human growth hormone and its receptor associated with low serum levels of insulin-like growth factor-1 and short stature.[19]

The genomes of Africans commonly found to undergo adaptation are regulatory DNA, and many cases of adaptation found among Africans relate to diet, physiology, and evolutionary pressures from pathogens.[20] Throughout Sub-Saharan Africa, genetic adaptation (e.g., rs334 mutation, Duffy blood group, increased rates of G6PD deficiency, sickle cell disease) to malaria has been found among Sub-Saharan Africans, which may have initially developed in 7300 BP.[20] Sub-Saharan Africans have more than 90% of the Duffy-null genotype.[21] In the rainforests of Central Africa, genetic adaptation for non-height-related factors (e.g., immune traits, reproduction, thyroid function) and short stature (e.g., EHB1 and PRDM5 – bone synthesis; OBSCN and COX10 – muscular development; HESX1 and ASB14 – pituitary gland’s growth hormone production/secretion) has been found among rainforest hunter-gatherers.[20]

References

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  1. ^ Osborne, Anne H.; et al. (October 2008). "A humid corridor across the Sahara for the migration of early modern humans out of Africa 120,000 years ago". Proceedings of the National Academy of Sciences of the United States of America. 105 (43): 16444–16447. Bibcode:2008PNAS..10516444O. doi:10.1073/pnas.0804472105. PMC 2575439. PMID 18936490. S2CID 10418009.
  2. ^ Drake, Nick; Breeze, Paul (2016). "Climate Change and Modern Human Occupation of the Sahara from MIS 6-2". Africa from MIS 6-2. Vertebrate Paleobiology and Paleoanthropology. Africa from MIS 6-2. pp. 103–122. doi:10.1007/978-94-017-7520-5_6. ISBN 978-94-017-7519-9. S2CID 131383927.
  3. ^ El-Shenawy, Mohammed I.; et al. (2018). "Speleothem evidence for the greening of the Sahara and its implications for the early human dispersal out of sub-Saharan Africa". Quaternary Science Reviews. 188: 67–76. Bibcode:2018QSRv..188...67E. doi:10.1016/j.quascirev.2018.03.016. S2CID 134694090.
  4. ^ Scheele, Judith (Aug 2016). Crossroads Regions: The Sahara. Oxford Handbooks Online. doi:10.1093/oxfordhb/9780199935369.013.18. ISBN 978-0-19-993536-9.
  5. ^ Wippel, Steffen (2020). "The Sahara as a Bridge, Not a Barrier: An Essay and Book Review on Recent Transregional Perspectives". Neue Politische Literatur. 65 (3): 449–472. doi:10.1007/s42520-020-00318-y. S2CID 224855920.
  6. ^ a b Bergström A, Stringer C, Hajdinjak M, Scerri EM, Skoglund P (February 2021). "Origins of modern human ancestry". Nature. 590 (7845): 229–237. Bibcode:2021Natur.590..229B. doi:10.1038/s41586-021-03244-5. PMID 33568824. S2CID 231883210.
  7. ^ González-Fortes, G.; et al. (2019). "A western route of prehistoric human migration from Africa into the Iberian Peninsula". Proceedings of the Royal Society B: Biological Sciences. 286 (1895): 20182288. doi:10.1098/rspb.2018.2288. PMC 6364581. PMID 30963949. S2CID 104296971.
  8. ^ Lipson M, Ribot I, Mallick S, Rohland N, Olalde I, Adamski N, et al. (January 2020). "Ancient West African foragers in the context of African population history". Nature. 577 (7792): 665–670. Bibcode:2020Natur.577..665L. doi:10.1038/s41586-020-1929-1. PMC 8386425. PMID 31969706. S2CID 210862788.
  9. ^ a b c Wang K, Goldstein S, Bleasdale M, Clist B, Bostoen K, Bakwa-Lufu P, et al. (June 2020). "Ancient genomes reveal complex patterns of population movement, interaction, and replacement in sub-Saharan Africa". Science Advances. 6 (24): eaaz0183. Bibcode:2020SciA....6..183W. doi:10.1126/sciadv.aaz0183. PMC 7292641. PMID 32582847.
  10. ^ a b c Wang K, Goldstein S, Bleasdale M, Clist B, Bostoen K, Bakwa-Lufu P, et al. (June 2020). "Ancient genomes reveal complex patterns of population movement, interaction, and replacement in sub-Saharan Africa". Science Advances. 6 (24): eaaz0183. Bibcode:2020SciA....6..183W. doi:10.1126/sciadv.aaz0183. PMC 7292641. PMID 32582847.
  11. ^ González M, Gomes V, López-Parra AM, Amorim A, Carracedo A, Sánchez-Diz P, et al. (March 2013). "The genetic landscape of Equatorial Guinea and the origin and migration routes of the Y chromosome haplogroup R-V88". European Journal of Human Genetics. 21 (3): 324–331. doi:10.1038/ejhg.2012.167. PMC 3573200. PMID 22892526.
  12. ^ a b c d Sá, Luísa; et al. (16 August 2022). "Phylogeography of Sub-Saharan Mitochondrial Lineages Outside Africa Highlights the Roles of the Holocene Climate Changes and the Atlantic Slave Trade". International Journal of Molecular Sciences. 23 (16): 9219. doi:10.3390/ijms23169219. ISSN 1661-6596. OCLC 9627558751. PMC 9408831. PMID 36012483. S2CID 251653686.
  13. ^ a b c Quintana-Murci L, Quach H, Harmant C, Luca F, Massonnet B, Patin E, et al. (February 2008). "Maternal traces of deep common ancestry and asymmetric gene flow between Pygmy hunter-gatherers and Bantu-speaking farmers". Proceedings of the National Academy of Sciences of the United States of America. 105 (5): 1596–1601. Bibcode:2008PNAS..105.1596Q. doi:10.1073/pnas.0711467105. PMC 2234190. PMID 18216239.
  14. ^ Sarah A. Tishkoff et al. 2007, History of Click-Speaking Populations of Africa Inferred from mtDNA and Y Chromosome Genetic Variation. Molecular Biology and Evolution 2007 24(10):2180-2195
  15. ^ Lluis Quintana-Murci et al. MtDNA diversity in Central Africa: from hunter-gathering to agriculturalism. CNRS-Institut Pasteur, Paris
  16. ^ Silva M, Alshamali F, Silva P, Carrilho C, Mandlate F, Jesus Trovoada M, et al. (July 2015). "60,000 years of interactions between Central and Eastern Africa documented by major African mitochondrial haplogroup L2". Scientific Reports. 5: 12526. Bibcode:2015NatSR...512526S. doi:10.1038/srep12526. PMC 4515592. PMID 26211407.
  17. ^ Jarvis JP, Scheinfeldt LB, Soi S, Lambert C, Omberg L, Ferwerda B, et al. (2012). "Patterns of ancestry, signatures of natural selection, and genetic association with stature in Western African pygmies". PLOS Genetics. 8 (4): e1002641. doi:10.1371/journal.pgen.1002641. PMC 3343053. PMID 22570615.
  18. ^ López Herráez D, Bauchet M, Tang K, Theunert C, Pugach I, Li J, et al. (November 2009). "Genetic variation and recent positive selection in worldwide human populations: evidence from nearly 1 million SNPs". PLOS ONE. 4 (11): e7888. Bibcode:2009PLoSO...4.7888L. doi:10.1371/journal.pone.0007888. PMC 2775638. PMID 19924308.
  19. ^ Bozzola M, Travaglino P, Marziliano N, Meazza C, Pagani S, Grasso M, et al. (November 2009). "The shortness of Pygmies is associated with severe under-expression of the growth hormone receptor". Molecular Genetics and Metabolism. 98 (3): 310–313. doi:10.1016/j.ymgme.2009.05.009. PMID 19541519.
  20. ^ a b c Pfennig, Aaron; et al. (March 29, 2023). "Evolutionary Genetics and Admixture in African Populations". Genome Biology and Evolution. 15 (4): evad054. doi:10.1093/gbe/evad054. OCLC 9817135458. PMC 10118306. PMID 36987563. S2CID 257803764.
  21. ^ Wonkam, Ambroise; Adeyemo, Adebowale (March 8, 2023). "Leveraging our common African origins to understand human evolution and health" (PDF). Cell Genomics. 3 (3): 100278. doi:10.1016/j.xgen.2023.100278. PMC 10025516. PMID 36950382. S2CID 257458855.
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