1 in 200 of our human genes can be inactivated with no detectable effect on our health. A study by Wellcome Trust Sanger Institute scientists raises new questions about the effects of gene loss on our wellbeing and evolution.
The study, published today in The American Journal of Human Genetics, explores single letter changes in our genetic code that affect the ability of genes to produce proteins. The researchers' findings suggest that such mutations, while sometimes harmful, generally have little consequence for the individual and may occasionally even be beneficial in evolutionary terms.
The team studied variations in the genetic code of more than 1000 people from around the world. They focused their work on single-letter changes (called SNPs) that disrupt proteins, leading to versions that are either shorter or completely absent. One might intuitively expect that such a change - called a nonsense-SNP - would be harmful to the person.
"We knew that these mutations existed and that many have been associated with genetic diseases, but we were amazed to find that they were so common in the general population," said Bryndis Yngvadottir, lead author on the study. "We found that 167 genes could be inactivated by nonsense mutations, and that individuals carry on average at least 46 such variations. For 99 of the genes, both copies could be lost in adults living a normal existence."
Human DNA contains approximately 20,000 genes: the total of 99 genes with nonsense-SNPs means that at least 1 in 200 genes is dispensable. Some harmful nonsense-SNPs were also present among the 167 genes studied: 8 are listed in the Human Gene Mutation Database which catalogues disease-causing mutations.
While the researchers found that inactivating genes was, on the whole, slightly harmful, there were exceptions. In East Asia, but not in other places, it seems to have been advantageous to lose the MAGEE2 gene.
"There is a theory that 'less is more' where genes are concerned" explained the study's coordinator, Chris Tyler-Smith, "and we already knew of a couple of examples of advantageous gene loss. But this is the first large-scale investigation of its significance for recent human evolution.
"The MAGEE2 gene is an interesting new example, although we have absolutely no idea what this gene does, or why some people are better off without it. However, our study suggests that overall, gene loss has not been a major evolutionary force: our genome does not seem to be in a hurry to get rid of these 'superfluous' genes."
"Certain types of genes tend to be lost preferentially. We found the biggest decrease in the genes that contribute to our sense of smell. Perhaps early humans didn't like smelly partners, and so when humans started to live together in big groups it helped their chances of finding true love if they couldn't smell their partner too strongly," speculated Bryndis Yngvadottir.
Genetic variation in nonsense-SNP numbers was significant: participants in the survey had between 29 and 65 of these mutations each and varied on average by 24 genes as a consequence. 18 of the 169 nonsense-SNPs investigated are also present in the Craig Venter genome published last year.
Innovative genetic tests for children with developmental disorders and epilepsy
11.07.2018 | Christian-Albrechts-Universität zu Kiel
Oxygen loss in the coastal Baltic Sea is “unprecedentedly severe”
05.07.2018 | European Geosciences Union
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
19.07.2018 | Earth Sciences
19.07.2018 | Power and Electrical Engineering
19.07.2018 | Materials Sciences