Unravelling the genetic characteristics and demographic history of human populations in diverse environments across North Asia and South America

The vast regions of North Asia and South America harbour diverse populations, often living in extreme environments. Genetic characteristics and the demographic history of the populations of the two regions remain understudied primarily because of the underrepresentation of the populations in large-s...

Full description

Saved in:
Bibliographic Details
Main Author: Ghosh, Amit Gourav
Other Authors: Kim Hie Lim
Format: Thesis-Doctor of Philosophy
Language:English
Published: Nanyang Technological University 2023
Subjects:
Online Access:https://hdl.handle.net/10356/170246
Tags: Add Tag
No Tags, Be the first to tag this record!
Institution: Nanyang Technological University
Language: English
id sg-ntu-dr.10356-170246
record_format dspace
spelling sg-ntu-dr.10356-1702462024-04-02T01:42:57Z Unravelling the genetic characteristics and demographic history of human populations in diverse environments across North Asia and South America Ghosh, Amit Gourav Kim Hie Lim Asian School of the Environment HLKIM@ntu.edu.sg Science::Biological sciences::Genetics Science::Biological sciences::Evolution The vast regions of North Asia and South America harbour diverse populations, often living in extreme environments. Genetic characteristics and the demographic history of the populations of the two regions remain understudied primarily because of the underrepresentation of the populations in large-scale whole-genome studies and public databases. To shed light on the genetic characteristics and demographic history of the populations, I analysed whole-genome sequencing data of 1537 individuals from 140 populations. The results show that the North Asian and South American populations consisted of 6 and 4 genetic ancestries, respectively, with complex episodes of admixtures. Demographic history analyses revealed the influence of the Neolithic revolution and past climate change in the decline of the Kets in North Asia. Demographic history analyses also revealed that the earliest settlers reached South America and underwent simultaneous population splits 14,000 years ago as they settled and isolated in different geographic regions to give rise to the contemporary regional population structure. I highlight the case of the endangered Patagonian population, Kawésqar, who migrated the longest distance since modern humans moved out of Africa. Such dramatic migration coupled with environment-mediated isolation led to high homogeneity and severe loss in immune gene (HLA genes) diversity, making them vulnerable to unencountered pathogens. Since indigenous populations in South America inhabit harsh and environmentally divergent regions, I show that such populations underwent differential genetic adaptations to survive such conditions and associated lifestyles. Overall, this study sheds light on the genetic diversity and historical dynamics of these fascinating yet understudied populations, highlighting their importance in deepening our understanding of human evolution and adaptation to different environmental conditions. Doctor of Philosophy 2023-09-05T02:27:52Z 2023-09-05T02:27:52Z 2023 Thesis-Doctor of Philosophy Ghosh, A. G. (2023). Unravelling the genetic characteristics and demographic history of human populations in diverse environments across North Asia and South America. Doctoral thesis, Nanyang Technological University, Singapore. https://hdl.handle.net/10356/170246 https://hdl.handle.net/10356/170246 10.32657/10356/170246 en This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0). application/pdf Nanyang Technological University
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
collection DR-NTU
language English
topic Science::Biological sciences::Genetics
Science::Biological sciences::Evolution
spellingShingle Science::Biological sciences::Genetics
Science::Biological sciences::Evolution
Ghosh, Amit Gourav
Unravelling the genetic characteristics and demographic history of human populations in diverse environments across North Asia and South America
description The vast regions of North Asia and South America harbour diverse populations, often living in extreme environments. Genetic characteristics and the demographic history of the populations of the two regions remain understudied primarily because of the underrepresentation of the populations in large-scale whole-genome studies and public databases. To shed light on the genetic characteristics and demographic history of the populations, I analysed whole-genome sequencing data of 1537 individuals from 140 populations. The results show that the North Asian and South American populations consisted of 6 and 4 genetic ancestries, respectively, with complex episodes of admixtures. Demographic history analyses revealed the influence of the Neolithic revolution and past climate change in the decline of the Kets in North Asia. Demographic history analyses also revealed that the earliest settlers reached South America and underwent simultaneous population splits 14,000 years ago as they settled and isolated in different geographic regions to give rise to the contemporary regional population structure. I highlight the case of the endangered Patagonian population, Kawésqar, who migrated the longest distance since modern humans moved out of Africa. Such dramatic migration coupled with environment-mediated isolation led to high homogeneity and severe loss in immune gene (HLA genes) diversity, making them vulnerable to unencountered pathogens. Since indigenous populations in South America inhabit harsh and environmentally divergent regions, I show that such populations underwent differential genetic adaptations to survive such conditions and associated lifestyles. Overall, this study sheds light on the genetic diversity and historical dynamics of these fascinating yet understudied populations, highlighting their importance in deepening our understanding of human evolution and adaptation to different environmental conditions.
author2 Kim Hie Lim
author_facet Kim Hie Lim
Ghosh, Amit Gourav
format Thesis-Doctor of Philosophy
author Ghosh, Amit Gourav
author_sort Ghosh, Amit Gourav
title Unravelling the genetic characteristics and demographic history of human populations in diverse environments across North Asia and South America
title_short Unravelling the genetic characteristics and demographic history of human populations in diverse environments across North Asia and South America
title_full Unravelling the genetic characteristics and demographic history of human populations in diverse environments across North Asia and South America
title_fullStr Unravelling the genetic characteristics and demographic history of human populations in diverse environments across North Asia and South America
title_full_unstemmed Unravelling the genetic characteristics and demographic history of human populations in diverse environments across North Asia and South America
title_sort unravelling the genetic characteristics and demographic history of human populations in diverse environments across north asia and south america
publisher Nanyang Technological University
publishDate 2023
url https://hdl.handle.net/10356/170246
_version_ 1795375044454514688