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Printable Handouts
Navigable Slide Index
- Introduction
- Evolution and diversity of humans
- Adaptive phenotypic variation
- Common diseases vary across populations
- Disease-related traits also vary
- Geographic distribution of human phenotypes
- The signature of selective sweeps
- Local adaptations due to selective sweeps
- Some traits show a clinal distribution
- Traits with discontinuous spatial distribution
- Genetic variants and environmental variables
- Subtle shifts in the frequency of standing variation
- Selection on standing variation
- Faster adaptive response
- Selective sweeps vs. polygenic adaptations
- Adaptive introgression
- Admixture & local adaptations
- High-altitude populations as a study system
- Tibetan highlanders and Hb phenotype
- Adaptive alleles: lower Hb levels in Tibetans
- Adaptive introgression of Tibetan EPAS1
- Searching for the origins of Tibetan adaptations
- Tibetans: mix of altitude ancestral components
- Adaptive alleles were maintained at high frequency
- Model of adaptive allele in admixed population
- EGLN1 and EPAS1 regions in Tibetans
- How to detect adaptation signals in a GWAS scan
- Impact of selective sweeps on human phenotypes
- Impact of different environmental aspects
- Climate correlations overlap with various traits
- Advantageous alleles in a selective sweep model
- Categories enriched for recent positive selection
- Polygenic adaptations generate only subtle shifts
- Polygenic adaptations & pathway analysis
- Role of convergent evolution in local adaptations
- Hb phenotypes in Tibetans and Ethiopian Amhara
- Tibetans don't share Hb variation loci with Amhara
- Convergent adaptations to high altitude
- Conclusions
Topics Covered
- Phenotypic diversity in human populations
- Selective sweeps
- Clines of allele frequency
- Selection on standing variation
- Polygenic adaptations
- Adaptive introgression
- Adaptations to high altitude
- Genome-wide evidence for local adaptations
- Interpreting the results of selection scans
- Convergent adaptations
Talk Citation
Di Rienzo, A. (2015, March 18). Local adaptations in humans [Video file]. In The Biomedical & Life Sciences Collection, Henry Stewart Talks. Retrieved December 5, 2024, from https://doi.org/10.69645/IFSM8033.Export Citation (RIS)
Publication History
Financial Disclosures
- Dr. Anna Di Rienzo has not informed HSTalks of any commercial/financial relationship that it is appropriate to disclose.
Other Talks in the Series: Human Population Genetics II
Transcript
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0:00
My name is Anna Di Rienzo from
the Department of Human Genetics at the University of Chicago.
Today, I will review recent studies about how
human populations adapted to the different environments in which they live.
I will review the models through which these adaptations took place,
some of the methods used to look for signals of
local adaptations and how to interpret their results.
I will describe some of the biological findings obtained in these studies.
0:39
Probably, one of the most striking aspects of evolution of
our species is that tremendous diversity of environments,
illustrated here by a map of the ecoregions,
that humans have encountered during their history and have adapted to.
Both genetic data and the fossil record
indicate that modern humans originated somewhere in Sub-Saharan Africa,
and from there they dispersed across the globe to
occupy every corner of the earth landmass.
In so doing, they have encountered a variety of environmental challenges,
including different climates, different levels of UV radiation,
different pathogens and available resources.
In addition, during this history they have introduced
a number of cultural and technological innovations,
which in turn have created new selective pressures.
In response to these environmental challenges,
human populations have evolved a number of cultural, behavioral,
as well as genetic adaptations that lead to that wonderful phenotypic
and cultural diversity that we see today in contemporary populations.