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 New study: How does Europe become a leading player for software and IT services?
03.04.2017 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Reusable carbon nanotubes could be the water filter of the future, says RIT study
30.03.2017 | Rochester Institute of Technology

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: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

DGIST develops 20 times faster biosensor

24.04.2017 | Physics and Astronomy

Nanoimprinted hyperlens array: Paving the way for practical super-resolution imaging

24.04.2017 | Materials Sciences

Atomic-level motion may drive bacteria's ability to evade immune system defenses

24.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>