Tracing the Geographical Origins of Human Genetic Diversity - A Possible Phylogeographic Scenario

Loosdrecht, M.S. van de (2011) Tracing the Geographical Origins of Human Genetic Diversity - A Possible Phylogeographic Scenario. Bachelor's Thesis, Biology.

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Abstract

Evidence underlining the Recent Out of Africa theory came from genetic diversity and population bottleneck studies that showed a restricted African origin for modern human dispersal and the non-African populations to be small subsets of the African gene pool; a genetic pattern most accurately explained by a serial founder effect. After the Recent Out of Africa theory was proposed, various researches suggested additional hypotheses on early Homo sapiens genetic and migration history to give more detailed explanations with regard to the origin of the observed diversity among populations from distinct geographical regions. The main aim of this thesis is trying to unify key findings from these studies into one congruent scenario to describe accurately the dynamics in early modern human population phylogeography, from the moment of origin in Africa till the initial settlement throughout the Asian, Oceanian and European continent. Human migration is thought to have originated in Southeast-Africa, the region that contains the highest genetic diversity found today and important ancient population radiations are thought to have occurred in Southwest-Africa. When the founder population left Africa ~85 kiloannum ago (kya), the population thus carried a selected gene pool. Early modern humans may have migrated from Africa to Eurasia along a northern route through the Levant, or along a southern route through the Arabian Peninsula. Since supporting evidence for each route focuses on different time periods, theoretically it is possible that both migrations routes were taken. The Multiple Route hypothesis combines both migration routes to describe human phylogeographic patterns: haplogroup M being the signature of an early southern route migration to Southeast-Asia and N of later northern route migration to West-Eurasia. The hypothesis assumes an African origin for haplogroups (L3)N and M. In contrast, the Single Southern Route hypothesis states that both M and N were carried out in one unique rapid migration event along a southern route to Southeast-Asia. West-Eurasia was colonized by an early offshoot of a South-Indian radiation. This hypothesis assumes an Asian origin for N and M. This thesis finds the Single Southern Route hypothesis the most accurate in describing human phylogeographic patterns. This hypothesis, completed by two additional explanations on human migration (back migration from Asia to Africa and a migration pause in the Levant area) are fundamental to the congruent scenario proposed in the conclusion of this thesis.

Item Type:	Thesis (Bachelor's Thesis)
Degree programme:	Biology
Thesis type:	Bachelor's Thesis
Language:	English
Date Deposited:	15 Feb 2018 07:45
Last Modified:	15 Feb 2018 07:45
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/9576

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