Neanderthals and Disease Genes Group E - Julia Walker, Kimmi Vo, S. Chiamaka Okorie, George Fabrikarakis, Scott Hill, Emily DePina Kelly Bower

What is a Neanderthal? A) An earlier kind of human B) An extinct species of human Kelly Bower

Neanderthal Origins At minimum, there have been 20 different kinds of hominids on earth over the last 4.4 million years First hominids originated in Ethiopia Earliest Neanderthals lived in Europe and western Asia approx. 200,000 years ago Left impressive records of themselves, great with stonework Kelly Bower

Kelly

Denisovan Origins Separate population from Neanderthals Related through Common Origin Both present in Eurasia when humans emerged from Africa Interbred with humans and Neanderthals Scott

Modern Humans Origins Homo Sapiens originated in Africa (100,000-200,000 years ago) Entered Europe (approx. 40,000 years ago) Had basic stone, antler and bone tools + basic culture (art, music, records) Neanderthals less advanced H. Sapiens only hominids present for approx. last 25,000 years Julia Walker

Gene Flow Possible Model Julia Walker

DNA Analysis Ancient DNA very difficult to work with Fragmentation begins very soon after death Average length of old molecules; approx. 100 base pairs Must amplify DNA fragments to study PCR: multiplication of DNA in test tube, brings back correct sequence George polymerase chain reaction

Comparison of DNA very revealing: Allow scientists to detect shared variants and estimate degree to which sequences related Can discover how populations related to one another, time since split and periods of expansion and contraction in size As population shrinks, genetic diversity declines Learn about dynamics of genetic change in populations over time George

What is NOT a benefit of DNA analysis? A) Clearly examine ancient DNA B) Detect shared variants C) Discover how populations relate to each other D) Estimate time since population split George

Neanderthal Genes in Modern Humans Neanderthals: extinct species of human - differing in DNA only by .12% Eurasia Modern humans: archaic homo sapiens evolved to anatomically modern humans solely in Africa Africa Kimmi Vo - so how does this affect us? We mainly originate from modern humans

Interbreeding between species Interbreeding w/ modern humans (homo sapiens) led to non-Africans Middle east, not Africa as most expected Neanderthal genes helped modern humans adapt to non- African environments We all have more Neanderthal genes that we think Kimmi

“Neanderthals Gave Us Disease Genes” New study: disease-causing genes arose from interbreeding with Neanderthals Interbreeding not thought possible in past Beneficial and malignant gene transfer Genome studies reveal: human genome 2-4% Neanderthal genes Emily

Neanderthal Genes Now Alleles enriched for genes affecting keratin filaments Genes not evenly distributed - found to affect skin and hair No sex-linked genes, many had harmful effects removed through natural selection infertility, sterilization Emily

What percent of the human genome has Neanderthal genes? B) 15% -24% C) 2% - 4% D) 6% - 10% Emily

Modern Day Impact Neanderthal DNA slowly “purged” from environment Largely-negative gene variants remain and have led to modern day diseases. Could these benefit in another way? Chiamaka -natural selection flushed out bad genes -we still have the DNA because admixture happened early in the evolutionary line

Neanderthal Genes In Us Type 2 diabetes Long-term depression Lupus Biliary Cirrhosis Markers that affect chance of Crohn’s disease Chiamaka -markers that increase/decrease chance of Crohn’s -don’t know if neanderthals also had these diseases or if they only passed on genes that affected the risks

Sources http://news.nationalgeographic.com/news/2010/05/100506-science-neanderthals-humans- mated-interbred-dna-gene/ https://bostoncollege.instructure.com/groups/149869/files/48889883/download?wrap=1 Tanstall, Ian. “Once We Were Not Alone.” Scientific American. 56-62. 1999. Print. http://www.bbc.com/news/science-environment-25944817

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