A 70-year-old man can enjoy the blessing of fatherhood to perfectly healthy children. That is practically a miracle quality-wise because the male gametes are being produced in huge amounts, 1000 per second to be exact. That amounts to about 30 billion a year. Each and every one of those sperms could potentially contribute by half to the formation of a human being. So how could this rapid production preserve and maintain the critical quality required? How could errors during the sperm production be avoided? Researchers have recently gained an insight into the molecular mechanism as released in the “Proceedings of the National Academy of Sciences”.

During the sperm production, there is an automatic quality control process. This control mechanism is strengthened by a specific genetic addition, present in both humans and great apes. The triggering factor is comprised of parts of an endogenous retrovirus, incorporated in our genome. 15 million years ago, this viral DNA was presumably incorporated in the genetic makeup of one of our ancestors. A lucky coincidence? Perhaps, but the researchers claim it catched on during the process of evolution. The site of insertion of this viral DNA is close to a gene, responsible for the production of a crucial control factor.
The control factor, termed p63, drives faulty cells straight to their apoptosis. It imposes a strict quality control of the genome because even in cases of a slight damage to the DNA, the cells ultimately die. As a result, the passing on of a flawed genome to the next generation is prevented. Some cells definitely fall as victims in the process. In addition, this mechanism could protect against certain types of cancer as testicular carcinoma. They refer that, p63 represents a barrier to the formation of tumors in normal healthy tissues. In cases of testicular cancer, the administration of drugs, that restore the function of p63, could prove potentially useful in the near future.

Source: Pharmazeutische Zeitung and original PNAS paper (thanks to Mariam and Steve Moss for sharing)