Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Human testes may multiply mutations

28.08.2007
The organs that produce sperm also may make it easier for mutations to pass to offspring, USC biologists say.

The testes in humans may act as mutation multipliers that raise the odds of passing improved DNA to offspring – but that can also backfire by increasing the frequency of certain diseases.

The new theory is part of a study, appearing in PLOS Biology, that tries to explain the puzzlingly high frequency of Apert syndrome, a genetic cranial deformity found in approximately one out of every 70,000 newborns.

The study’s authors suggest that natural selection may favor “germline” cells – the precursors to sperm – carrying a mutation that causes Apert syndrome.

A competitive advantage for mutated sperm precursor cells could explain why Apert strikes 100 to 1,000 times more people than expected from a single mutation.

Useful mutations in sperm precursor cells also may be more likely to pass to the next generation, the authors suggest, “because the effective mutation frequency is elevated beyond the level that can be achieved by the molecular mutation process alone.”

Why natural selection might favor sperm precursor cells carrying a disease mutation is not yet understood.

The authors based their conclusions on an analysis of four human testes and computer models of mutation frequency.

They say their study is the first to check the location of mutant germline cells in the testes in any species. The result was surprising.

“You would expect that when a new mutation arose, it could arise virtually anywhere in the organ,” said Norman Arnheim, holder of the Ester Dornsife Chair in Biological Sciences at USC and one of the co-leaders of the project along with computational biologist Peter Calabrese.

“But when we divided the testes up, we didn’t find that. What we found were some very big clusters of precursor cells that were mutant.”

The data did not support the theory that the site of the mutation in the Apert gene is unusually prone to DNA change.

Another explanation – that the mutations arise very early in the life of a germline cell and multiply through subsequent divisions – also did not fit the data, Arnheim and Calabrese said.

But the clusters of mutant cells could be explained if the mutant cells made copies of themselves more frequently than normal cells.

If a mutant cell divided into two copies of itself every four to five years, the extra copies would be enough to explain the clusters, the researchers said.

They added that the model explains the increase in Apert risk with paternal age, while noting that other selection-based models also may be able to explain the same data.

Citing related studies along with their findings, the authors concluded that “it now seems very likely that (natural) selection can be a driving force acting to increase the mutation frequency at a number of genes in humans.”

Carl Marziali | EurekAlert!
Further information:
http://www.usc.edu

More articles from Studies and Analyses:

nachricht Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas
17.03.2017 | University of Maryland

nachricht Diabetes Drug May Improve Bone Fat-induced Defects of Fracture Healing
17.03.2017 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>