IFG – Institut für forensische Genetik Münster, Prof. Dr. Bernd Brinkmann

Elevated mutation rate in teenage fathers

Press release – for the published manuscript follow this link

A survey of 24,097 parents and their children show that the children of teenage fathers have unexpectedly high levels of DNA mutations. Teenage fathers evidently have sperm cells with about 6 times more DNA mutations than the egg cells of teenage girls. And it seems their sperm cells have about 30% more mutations than those of 20-year-old men. This could explain why children from teenage parents have a higher risk for autism, schizophrenia, low birth weight, spina bifida, and other defects. It should be noted though that only 1.5 percent of babies on average have abnormalities, hence an increase by 30 percent to 2 percent of births is still a small percentage.

The reason for the excessive DNA mutations in teenage fathers‘ children is not yet clear. Possibly the DNA copying mechanism is particularly error-prone at the beginning of male puberty. Or, sperm production in boys may undergo dozens more cell cycles (and therefore DNA copying errors) than has previously been suspected.

The type of DNA analysed in this survey is repetitive DNA known as microsatellites, which the authors have used to track the number of times that a cell divides. It will now be important to investigate whether other types of DNA mutations are also increased in the children of teenage fathers.

The research was conducted in Cambridge, in Salzburg (Austria), and in Muenster (Germany) by Professor Brinkmann’s Institute for Forensic Genetics (IFG.MS) and the Institute of Legal Medicine.

FIGURE LEGEND

Section of a normal testes of a young man (Picture courtesy of Professor Stefan Schlatt, University of Muenster, Germany).

The testis consists of two compartments: the seminiferous tubules with
the seminiferous epithelium, and the interstitial space. Seminiferous
tubules are surrounded by a basement membrane. Spermatogenesis is
initiated from spermatogonial stem cells in attachment to the lamina,
and ends with mature spermatids which are released into the lumen of the
tubule.

It has long been suspected that as men age, their stem cells incur more and more DNA copying errors, producing sperm with increasingly mutated DNA. But the current research unexpectedly shows that teenage males also produce mutated sperm at about the same error rate as 30-40-year-old men. It appears that the spermatogonial cells accumulate DNA errors unnoticed during childhood, or commit DNA errors at an especially high level at the onset of puberty.

Contact: Dr. Carsten Hohoff hohoff@ifg-ms.de

see also the Cambridge university
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