{"id":1934,"date":"2015-01-28T19:59:26","date_gmt":"2015-01-28T19:59:26","guid":{"rendered":"http:\/\/healthmedicinet.com\/news\/did-genetic-links-to-modern-maladies-provide-ancient-benefits\/"},"modified":"2015-01-28T19:59:26","modified_gmt":"2015-01-28T19:59:26","slug":"did-genetic-links-to-modern-maladies-provide-ancient-benefits","status":"publish","type":"post","link":"http:\/\/healthmedicinet.com\/news\/did-genetic-links-to-modern-maladies-provide-ancient-benefits\/","title":{"rendered":"Did genetic links to modern maladies provide ancient benefits?"},"content":{"rendered":"

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IMAGE:\u00c2\u00a0<\/strong>A reconstruction of Homo neanderthalensis<\/i>, as created by artist John Gurche for the Smithsonian\u00e2\u20ac\u2122s National Museum of Natural History. A study led by University at Buffalo biologist Omer Gokcumen compared\u00e2\u20ac\u00a6
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Credit: From Shaping Humanity, by John Gurche. <\/p>\n

Image may be republished ONLY in conjunction with stories about the research outlined in this press release.<\/p>\n<\/figcaption>\n<\/p>\n<\/figure>\n

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BUFFALO, N.Y. \u00e2\u20ac\u201d Psoriasis, a chronic skin condition, can cause rashes that itch and sting.<\/p>\n

So why would a genetic susceptibility to this and other ailments persist for hundreds of thousands of years, afflicting our ancient ancestors, and us?<\/p>\n

That\u00e2\u20ac\u2122s the question scientists are asking after discovering that genetic variations associated with some modern maladies are extremely old, predating the evolution of Neanderthals, Denisovans (another ancient hominin) and contemporary humans.<\/p>\n

The study was published this month in Molecular Biology and Evolution<\/em>. <\/p>\n

\u00e2\u20ac\u0153Our research shows that some genetic features associated with psoriasis, Crohn\u00e2\u20ac\u2122s disease and other aspects of human health are ancient,\u00e2\u20ac\u009d says senior scientist Omer Gokcumen, PhD, a University at Buffalo assistant professor of biological sciences. <\/p>\n

Some of humanity\u00e2\u20ac\u2122s early ancestors had the telltale features, called deletions, while others did not, mirroring the variation in modern humans, the scientists found. This genetic diversity may have arisen as far back as a million or more years ago in a common ancestor of humans, Denisovans and Neanderthals.<\/p>\n

The discovery highlights the importance of balancing selection, a poorly understood evolutionary dance in which dueling forces drive species to retain a diverse set of genetic features.<\/p>\n

The research raises the possibility that the diseases in question \u00e2\u20ac\u201d or at least a genetic susceptibility to them \u00e2\u20ac\u201d \u00e2\u20ac\u0153may have been with us for a long time,\u00e2\u20ac\u009d Gokcumen says.<\/p>\n

Why this would happen is an open question, but one possibility is that certain traits that made humans susceptible to Crohn\u00e2\u20ac\u2122s and psoriasis may also have afforded an evolutionary benefit to our ancient ancestors. <\/p>\n

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Dueling forces shape evolution:<\/p>\n<\/p>\n

Though we often think of evolution as black and white \u00e2\u20ac\u201d a trait is either good or bad \u00e2\u20ac\u201d there are instances where the line is not so clear, Gokcumen says.<\/p>\n

\u00e2\u20ac\u0153The best example of this is sickle cell anemia,\u00e2\u20ac\u009d he explains. The disorder causes red blood cells to take on a curved, crescent-like shape, which leads to anemia (a problem), but also protects against malaria by keeping parasites out of cells (an advantage). These opposing pressures create a balance where the copy of the gene that causes the sickle cell anemia remains in the population in malaria-ridden geographies.<\/p>\n

The new study hints that the ancient deletions that are associated with Crohn\u00e2\u20ac\u2122s disease and psoriasis may play similar \u00e2\u20ac\u201d but likely more complex \u00e2\u20ac\u201d roles in health.<\/p>\n

\u00e2\u20ac\u0153Crohn\u00e2\u20ac\u2122s disease and psoriasis are damaging, but our findings suggest that there may be something else \u00e2\u20ac\u201d some unknown factor now or in the past \u00e2\u20ac\u201d that counteracts the danger when you carry genetic features that may increase susceptibility for these conditions,\u00e2\u20ac\u009d Gokcumen says. \u00e2\u20ac\u0153Both diseases are autoimmune disorders, and one can imagine that in a pathogen-rich environment, a highly active immune system may actually be a good thing even if it increases the chances of an auto-immune response.\u00e2\u20ac\u009d<\/p>\n

Ancient genetic variations maintained due to opposing evolutionary pressures may be \u00e2\u20ac\u0153underappreciated,\u00e2\u20ac\u009d says Yen-Lung Lin, a PhD candidate in UB\u00e2\u20ac\u2122s Department of Biological Sciences who is lead author in the study. \u00e2\u20ac\u0153We\u00e2\u20ac\u2122re thinking forces that maintain variation might be more relevant to human health and biology than previously believed.\u00e2\u20ac\u009d<\/p>\n

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Important genetic variations predate Neanderthals<\/p>\n<\/p>\n

Gokcumen\u00e2\u20ac\u2122s team compared modern human genomes to those of other closely related species, including chimpanzees and two archaic hominins: Neanderthals and Denisovans, both of which evolved hundreds of thousands of years ago and whose genomes were sequenced by other scientists using ancient remains.<\/p>\n

Gokcumen\u00e2\u20ac\u2122s team identified chunks of DNA that exist in chimpanzees but that were later erased through evolutionary processes. These DNA segments are called deletions, and today, they are present in some human genomes and missing from others. <\/p>\n

The study found that certain functionally important deletions that vary among modern humans likely originated in a common ancestor of humans, Neanderthals and Denisovans, possibly dating as far back as a million or more years ago. These unusually old deletions included ones that are common in Crohn\u00e2\u20ac\u2122s disease and psoriasis patients, as well as deletions linked to a person\u00e2\u20ac\u2122s ability to respond to a number of drugs, including growth hormone treatments.<\/p>\n

In the past, scientists have conducted similar studies examining genetic variations that consist of a single unit of DNA called a nucleotide. The new research investigated longer sequences of DNA, taking advantage of recently available genomic data for modern and ancient hominins. The study demonstrates the power of leveraging such data to investigate different types of genetic differences among humans and to illuminate our species\u00e2\u20ac\u2122 genetic history.<\/p>\n

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Collaborators: <\/p>\n<\/p>\n

Gokcumen and Lin\u00e2\u20ac\u2122s co-authors included Jerry Ajay in UB\u00e2\u20ac\u2122s Department of Computer Science and Engineering, Pavlos Pavlidis of the Institute of Molecular Biology and Biotechnology, part of the Foundation for Research and Technology-Hellas in Greece, and Emre Karakoc from Max Planck Institute for Evolutionary Biology.<\/p>\n","protected":false},"excerpt":{"rendered":"

IMAGE:\u00c2\u00a0A reconstruction of Homo neanderthalensis, as created by artist John Gurche for the Smithsonian\u00e2\u20ac\u2122s National Museum of Natural History. A study led by University at Buffalo biologist Omer Gokcumen compared\u00e2\u20ac\u00a6 view more Credit: From Shaping Humanity, by John Gurche. Image may be republished ONLY in conjunction with stories about the research outlined in this press […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[],"tags":[],"class_list":["post-1934","post","type-post","status-publish","format-standard","hentry"],"_links":{"self":[{"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/posts\/1934","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/comments?post=1934"}],"version-history":[{"count":0,"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/posts\/1934\/revisions"}],"wp:attachment":[{"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/media?parent=1934"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/categories?post=1934"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/healthmedicinet.com\/news\/wp-json\/wp\/v2\/tags?post=1934"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}