In another stunning example of unintended consequences, Icelandic researchers have discovered with older fathers, which have lately been the trend in western society, there are far greater chances for mutations than in dads that have their children younger. The reason for this surprising revelation is simple; since sperm multiply by dividing, and mutations are likely to occur during this process, the older the man, the more often his sperm have divided.
On the other hand, because women receive their eggs all at once, early on in life, they are not subject to the same constant replacement by division. This indicates, according to the research team, that when mutations occur, it is much likelier from the sperm being mutated than the egg.
The findings, which were reported in the influential science journal Nature, warned that with the average age of fatherhood having gone from 28 to 33, between the years 1980 to 2011, it caused the mutation count to go from 60 to 70. This is a remarkably swift societal change in relative terms. The increased risk could mean an heightened incidence of such conditions as autism.
Kári Stefánsson, who is in charge of “deCODE”, a genetics-based company in Reykjavik, was quick to point out, however, in the early days of Icelandic settlement, men didn’t have opportunities for fatherhood until they were in their mid-thirties and there wasn’t a spate of autistic children being sired. Still, there is no doubting that the older dads do carry with them more opportunity for mutations than their younger counterparts. Not all mutation are bad, though, the researchers were quick to point out. The chance of having razor blade adorned knuckles or the ability to shoot lasers from your eyes a la X-Men is not very likely. Still, without mutations there can be no evolutionary process that allows a species to adapt. Natural selection is there to weed out the non-helpful mutations. Unfortunately, some mutations cause tragic and heart-rending deformities in some cases.
“You could argue what is bad for the next generation is good for the future of our species,” Stefánsson suggested in the Nature article.