Corporate Banner
Satellite Banner
Genomics
Scientific Community
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Humans and Chimps Share Genetic Strategy in Battle Against Pathogens

Published: Tuesday, February 19, 2013
Last Updated: Tuesday, February 19, 2013
Bookmark and Share
Findings point to common ancestry.

A genome-wide analysis searching for evidence of long-lived balancing selection—where the evolutionary process acts not to select the single best adaptation but to maintain genetic variation in a population—has uncovered at least six regions of the genome where humans and chimpanzees share the same combination of genetic variants.

The finding, to be published Feb. 14 in the journal Science, suggests that in these regions, human genetic variation dates back to a common ancestor with chimpanzees millions of years ago, before the species split. It also highlights the importance of the dynamic co-evolution of human hosts and their pathogens in maintaining genetic variation.

Balancing selection allows evolution to keep all hereditary options open. The classic human example is the persistence of two versions of the hemoglobin gene: a normal version and hemoglobin S., a mutation that distorts the shape and function of red blood cells. Those who inherit two normal hemoglobin genes are at high risk for malaria, a parasitic disease that infects more than 200 million people each year. Those who inherit one normal gene and one hemoglobin S. gene are partially protected from malaria—a potentially life-saving benefit. Those with two copies of the gene suffer from sickle-cell anemia, a serious and lifelong circulatory disease.

“When we looked for genetic clues pointing to other, more ancient, examples of balancing selection, we found strong evidence for at least six such regions and weaker evidence for another 119—many more than we expected,” said study author Molly Przeworski, PhD, professor of human genetics and of ecology and evolution at the University of Chicago.

“We don’t yet know what their functions are,” she said. None of the six regions codes for a protein. There are clues that they are involved in host-pathogen interactions, “but which pathogens, what immune processes,” she said, “we don’t know.”

The researchers used genetic data from 10 chimpanzees from Western Africa and 59 humans from sub-Saharan Africa who were part of the 1,000 Genomes Project.

The scientists looked for cases in which genetic variations that arose in the ancestor of humans and chimpanzees have been maintained through both lines. The fact that variation in these regions of the genome has persisted for so long argues that they “must have been functionally important over evolutionary time,” said Ellen Leffler, a graduate student in Przeworski’s laboratory and first author of the study.

The researchers, from the University of Chicago and Oxford University, designed the study to be very conservative. “We wanted to find the cases we believed the most, rather than the most cases,” Przeworski said.

Computers sorted snippets of the genetic data from humans and chimps into clusters, depending on how similar the subjects were to each other. For almost every snippet, they found a cluster of humans and a separate cluster of chimpanzees, as expected. But there were a few segments of the genomes in which each cluster included both chimpanzees and humans; in those regions, some humans were more closely related to some chimpanzees than to other humans.

“Instances in which natural selection maintains genetic variation in a population over millions of years are thought to be extremely rare,” the authors wrote. The oldest and best known example of balanced polymorphism shared between humans and chimpanzees is the major histocompatibility complex (MHC), a group of genes that help the immune system distinguish between the body and potential invaders, such as bacteria or viruses.

Last year, a team led by Przeworski found that humans and gibbons shared genetic variation related to the ABO blood-group system from a common ancestor.
The six new examples of balanced selection described in this study appear to play a role, like the

MHC, in fending off infectious disease. This requires a variety of evolutionary tools, including balancing selection. When a population moves to a new environment—for example the exodus out of Africa to northern Europe—they face many one-time adjustments, such as adapting to less intense sunlight and decreased ultraviolet radiation. Over many generations, their offspring manage to decrease melanin production—a static adaptation for a static environment.

Fighting off pathogens is more dynamic, a constant arms race. Balancing selection may have enabled humans and chimps to retain multiple lines of defense that can be called on when a pathogen evolves new weapons.

“Our results imply that dynamic co-evolution of human hosts and their pathogens has played an important role in shaping human variation,” Przeworski said. “This highlights the importance of a different kind of selection pressure in human evolution.”


Further Information

Join For Free

Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 3,500+ scientific posters on ePosters
  • More than 5,000+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

Grad Student's Finding Enables Rapid Compound Screening
Grad student makes technical leap that could enable rapid screening of anti-cancer compounds.
Friday, August 19, 2016
From Fins to Fingers
New gene-editing methods help the mapping of cells linking fish fins and mammalian limbs.
Friday, August 19, 2016
New Technique Targets Ataxia Gene
Scientists selectively turn off the disease-causing portion of a gene that causes a severe form of ataxia.
Thursday, July 14, 2016
New Microbiome Center to Merge Expertise of UChicago, MBL and Argonne
Researchers to study world of microbes across environments.
Wednesday, May 18, 2016
New Code for Control of Gene Expression
A new cellular signal discovered by a team of scientists at the University of Chicago and Tel Aviv University provides a promising new lever in the control of gene expression.
Thursday, February 18, 2016
Enormous Genetic Variation May Shield Tumors from Treatment
Debate over Darwinian selection vs. random mutations emerges at the tumor level.
Wednesday, November 11, 2015
Gut Bacteria Can Dramatically Amplify Cancer Immunotherapy
Manipulating microbes maximizes tumor immunity in mice.
Monday, November 09, 2015
New Form of DNA Modification May Carry Inheritable Information
Scientists have described the surprising discovery and function of a new DNA modification in insects, worms and algae.
Friday, May 08, 2015
Researchers Identify ‘Fat Gene’ Associated with Obesity
Mutations within the gene FTO have been implicated as the strongest genetic determinant of obesity risk in humans, but the mechanism behind this link remained unknown.
Monday, March 17, 2014
Genetic Analysis Reveals Insights into Genetics of OCD, Tourette’s
Major differences between the genetic makeup of obsessive-compulsive disorder and Tourette’s syndrome, providing the first direct confirmation that both are highly heritable.
Tuesday, November 05, 2013
Graeme Bell Receives International Diabetes Prize
Prize includes a certificate of honor, a Japanese objet d’art and a $150,000 prize.
Tuesday, December 18, 2012
Study Points to New Target for Cancers Resistant to Certain Drugs
A more sensitive method to analyze protein interactions has uncovered a new way that cancer cells may use the cell-surface molecule HER3 to drive tumor progression following treatment with HER1 and HER2 inhibitors.
Tuesday, September 11, 2012
Grapefruit Juice Lets Patients Take Lower Dose of Cancer Drug
First cancer study to harness drug-food interaction.
Thursday, August 09, 2012
Guidelines for Prostate Screening Widely Ignored, Study Finds
2008 recommendations from federal task force had no impact.
Monday, April 30, 2012
Chicago Cancer Genome Project Studies Genetics of 1,000 Tumors
Analyzing the genetics of cancers from different parts of the body may reveal surprising details for treatment and prevention.
Tuesday, December 29, 2009
Scientific News
Faecal Bacteria Linked to Body Fat
Researchers at King’s College London have found a new link between the diversity of bacteria in human poo – known as the human faecal microbiome - and levels of abdominal body fat.
Scientists Find Lethal Vulnerability in Treatment-Resistant Lung Cancer
The study describes how the drug Selinexor killed lung cancer cells and shrank tumors in mice when used against cancers driven by the aggressive and difficult-to-treat KRAS cancer gene.
How Baby’s Genes Influence Birth Weight And Later Life Disease
The large-scale study could help to target new ways of preventing and treating these diseases.
Genes Underlying Dogs’ Social Ability Revealed
The social ability of dogs is affected by genes that also seem to influence human behaviour, according to a new study from Linköping University in Sweden.
‘Cellbots’ Chase Down Cancer, Deliver Drugs Directly to Tumors
Programmable T cells shown to be versatile, precise, and powerful in lab studies.
Modified Yeast Shows Plant Response to Key Hormone
Researchers have developed a toolkit based on modified yeast to determine plant responses to auxin.
ReadCoor Launched to Commercialize 3D Sequencing Tech
ReadCoor will leverage the Wyss Institute’s method for simultaneously sequencing and mapping RNAs within cells and tissues to advance development of diagnostics.
NCI Collaborates with Multiple Myeloma Research Foundation
NCI collaborates with MMRF to incorporate genomic and clinical data into NCI Genomic Data Commons database.
Epigenetic Clock Predicts Life Expectancy
New research finds 5 percent of population ages faster, faces shorter lifespan.
Regulatory RNA Essential to DNA Damage Response
Researchers discover a tumour suppressor is stabilized by an RNA molecule, which helps cells respond to DNA damage.
Skyscraper Banner

SELECTBIO Market Reports
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
3,500+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
5,000+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!