Late Marriage May Bring Genetic Mutations in Offsprings

Genetic science has been of great interest in the scientific world as it constitutes some of the most important linkages to our evolution. Still clouded with mystery, the DNA study keeps revealing new and interesting facts about our human body. Here is something about how late marriage may bring about genetic mutations. Over the years, late marriages seem to be the trend as people like to get themselves placed at a better financial position before tying the knot. Little do they realize that there might be a risk of creating complications in their offsprings. Elderly fathers pass along many more DNA errors than do young ones a source of genetic diversity, but also a possible driver of autism and other disorders. However, that is not always the case.

As men age, they are more likely to pass genetic mutations on to their children. By introducing change, older men’s’ genes appear to be a major driving force in human evolution, says Kari Stefansson, founder of the company deCODE Genetics and author of a study published in August. But the mutations from a growing number of older fathers may also account for a portion of the recent increase in autism. Jill Neimark shares some interesting facts in Discover Magazine.

Because the cells that give rise to sperm divide frequently—about 23 times a year—they are much more likely to accumulate genetic copying errors than the female precursor cells, oocytes, which divide only twice before becoming eggs. The mistakes add up over a lifetime so that the older the father, the more mutations he has in his sperm. Stefansson and his colleagues estimate that a 70-year-old dad passes on eight times as many mutations as does a 20-year-old.

To grasp the implications, Stefansson’s team compared the whole-genome sequences of 78 Icelandic people diagnosed with autism or schizophrenia with the sequences of their fathers and mothers. Four times as many of the childrens new genetic mutations came from their fathers as from their mothers. Similar results were announced in April and September by bioinformatician Evan Eichler at the University of Washington in Seattle, who demonstrated that the mutation rate in men rises linearly with age. A father 50 or older is about twice as likely as one 29 or under to have an autistic child, Eichler says.

Also in April of last year, Yale University geneticist Matthew State further quantified that risk. In families that have only one autistic child, he found, about 15 percent of the cases are linked to new mutations in sperm cells. Other studies suggest that offspring of older dads are at higher risk of schizophrenia, bipolar disorder, and epilepsy as well. Overall, advanced paternal age probably accounts for 5 percent to more than 25 percent of the risk for autism, depending on whom you ask. Because the average age of fatherhood is rising in many Western countries, more mutations are probably being passed along.

Ultimately, older fathers are a double-edged sword. Most of the mutations they pass on are harmless and some may be beneficial, even essential to our long-term survival as a species, since a genetically varied population is the raw material of evolutionary change. “Though mutations can be dangerous for the next generation,” Stefansson says, “they also increase the diversity in our genome.”

So it may be a wiser option to get married early and have a better chance of healthy offsprings. There are other complications as well with late marriage for example, the generation gap tends to be more(from a conservative standpoint). Or if you may look at it from another perspective, take the risk for the greater good and bring to life a lineage of advanced mutated children and make the much-needed paradigm shift in the society.

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Source

• Discover Magazine, Jill Neimark