Transcript The Effect of Mating with Neanderthals and Denisovans on our

The Effect of Mating with
Neanderthals and Denisovans
on our Immune system
Group A10
Gerald Duncan, Olivia Lahay, Madeline
Lionberger, Kyle Sledge, Heather Yutko
Introduction
• HLA (human leukocyte antigen): Genes important in immune
system response
• Haplotype: Combination of alleles transmitted together
• Ligand: binds to receptors
• Natural Killer Cells: Integral part of immune system
• Denisovans: group similar to Neanderthals
• Balancing selection: Multiple alleles maintained in population
• Introgression: Gene flow between hybrids and parental
populations
• Admixture: Mixing formerly unexposed populations
Data/Results
• Study led by Stanford University
• Human migration from Africa occurred 67,500 years ago
• Maximum of 4% of modern Eurasian genomes can be traced
back to Neanderthals
• Maximum of 4-6% of modern Melanesian genomes can be
traced back to Denisovans
• Thousands of alleles per HLA
http://images.dailytech.com/nimage/21570_large_HLA_B_Protein.jpg
Model of a HLA-B Protein
Data/Results (Cont’d)
• Percentage of HLA-A deviations believed (Abi-Rached) to be
from sexual activity with extinct races:
I. European: 50%
II. Chinese: 70%
III. Papua New Guinean: 95%
• 50-60 % of Chinese inhabitants possess A*11
• Very rare in African regions
http://www.sciencemag.org/content/334/6052/89/F2.large.jpg
http://www.sciencemag.org/content/334/6052/89/F3.large.jpg
Discussion
• The findings suggest:
I.
II.
• HLA:
I.
II.
III.
IV.
Interbreeding between archaic humans and Homo
sapiens.
Adaptive introgression of HLA genes.
Control NK cells
T cell immunity
Highly polymorphic---different alleles
Vital immune system component
Conclusion
•
•
Some HLA alleles in modern humans may have
originated from extinct human species.
These alleles may contribute to defending against
locally prevalent diseases.
Literature Cited
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Abi-Rached, Jobin, Kulkami, McWhinnie, Dalva, Gragert, Babrzadeh, Gharizadeh, Luo, Plummer, Kimani, Carrington,
Middleton, Rajalingam, Beksac, Marsh, Maiers, Guethlein, Tavoularis, Little, Green, Norman & Parham. 2011.
“The Shaping of Modern Human Immune Systems by Multiregional Admixture with Archaic Humans.” Science
Mag, online. http://www.sciencemag.org/content/334/6052/89.full
Freeman, Scott. Biological Science. 4th ed. San Francisco: Person Education, Inc, 2011. Print.
Handbook of Statistical Genetics. 3rd ed. Eds. D.J. Balding, M. Bishop., C. Cannings. Chichester: John Wiley & Sons, Ltd,
2007. Print.
“Haplotype.” genome.gov. National Human Genome Research Institute. Web. 17 November 2012.
http://www.genome.gov/Glossary/index.cfm?id=99
McGrath, Matt. “Neanderthal sex boosted immunity in modern humans.” BBC News, online.
http://www.bbc.co.uk/news/science-environment-14673047
Mick, Jason. “Neanderthal Sex Gave Europeans and Asians Stronger Immune Systems.” Daily Tech, online.
http://www.dailytech.com/Neanderthal+Sex+Gave+Europeans+and+Asians+Stronger+Immune+Systems/article22
555.htm
Rhymer, Judith M and Daniel Simberloff. “Extinction by Hybridization and Introgression.” Annual Reviews Inc., 1996. Web.
17 November 2012. http://www.annualreviews.org/doi/pdf/10.1146/annurev.ecolsys.27.1.83
Sample, Ian. “The Downside of Sex with Neanderthals.” The Guardian, online.
http://www.guardian.co.uk/science/blog/2011/aug/25/neanderthal-denisovan-genes-human-immunity
Vivier E, Tomasello E, Baratin M, Walzer T, Ugolini S. “Functions of natural killer cells.” Nat Immunol, May 2008. Web. 17
November 2012. http://www.ncbi.nlm.nih.gov/pubmed/18425107
Young, Ed. “Did sex with Neanderthals and Denisovans shape our immune system? The jury’s still out.” Discover Magazine,
online. http://blogs.discovermagazine.com/notrocketscience/2011/08/25/did-sex-with-neanderthals-anddenisovans-shape-our-immune-systems-the-jury%E2%80%99s-still-out/