The study, conducted by a team of researchers in Italy, also suggests that you might blame parasites for sculpting some of those genes into risk factors for intestinal disorders.
Parasite-driven selection leaves a footprint on our DNA in the form of mutations known as "single nucleotide polymorphisms" (SNPs). Making sure that genetic variation (in the form of multiple SNPs) is maintained within certain immune genes over time helps ensure that the host can fend off different infections in different environments.
In the new study, Matteo Fumagalli and colleagues sift through 1,052 SNPs in genes that code for immune proteins called interleukins from roughly 1000 people worldwide. Of 91 genes assessed, 44 bore signatures of evolutionary selection, meaning that the genetic variation was neither due to chance nor to the migration of populations over time. And some of that variation correlated with the diversity of parasites that live alongside humans. The data suggests that having lots of different parasites around has shaped the evolution of our interleukin genes.
In general, parasitic worms appear to have had a more powerful influence on certain interleukin genes than smaller microbes such as viruses, bacteria, and fungi. That isn't surprising, says senior author Manuela Sironi, because worms typically evolve slower than bacteria or viruses, giving their human hosts time to adapt in response. Some of the genes that were shaped by worm diversity made perfect sense, as the proteins they encode help generate the precise type of immune response required to rid the body of worms.
Other genes, however, seemed to be influenced more by the diversity of viruses, bacteria, and fungi than by that of worms. SNPs in some of these genes are known risk alleles for inflammatory bowel diseases, such as Crohn's and celiac disease. These "risky" alleles were probably maintained during evolution because they promote the kind of immune response needed to fend off viruses and bacteria. But this type of response also contributes to inflammatory bowel diseases.
Fumagalli, M., et al. 2009. J. Exp. Med. doi: 10.1084/jem.20082779
Amy Maxmen | EurekAlert!
Not of Divided Mind
19.01.2017 | Hertie-Institut für klinische Hirnforschung (HIH)
CRISPR meets single-cell sequencing in new screening method
19.01.2017 | CeMM Forschungszentrum für Molekulare Medizin der Österreichischen Akademie der Wissenschaften
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
19.01.2017 | Earth Sciences
19.01.2017 | Life Sciences
19.01.2017 | Physics and Astronomy