Elderly fathers transmit more genetic mutations to their children than older mothers. This was stated by scientists who studied the genomes of thousands of Icelandic parents and children. The authors of the scientific work hope to understand which mutations put children at risk for the occurrence of rare diseases.
New mutations are genetic changes that first appear in the embryo (they were not present in previous generations). They are key factors in evolution, but some of them can be dangerous.
“A huge percentage of rare diseases in children lies in mutations that are not present in their parents,” says deCODE geneticist Kári Stefánsson. “It’s important to find out where these mutations come from.”
And to find out, Stefansson and his colleagues sequenced the genomes of 14,688 Icelanders. The researchers used two different approaches, including comparing the genomic sequences of individuals with their parents, children, brothers and sisters.
“If the sequence is missing from the parents, but is present in the child, then it is new,” explains Stefansson.
They found that 80 percent of the new mutations come from the father, and that the number of mutations increases in accordance with the age of the parents.
According to experts, it is quite clear that age affects male sex cells more than women. Women are believed to be born with all the eggs that alternately ovulate throughout their lives. And although these cells are aging, they do not divide. On the other hand, men constantly produce new spermatozoa, and each cell division carries the risk of creating a new genetic mutation.
These mutations will not be harmful. We are all born with at least 70 new mutations, and most of them do not affect our body and brain, the researchers say.
Other works have shown that fathers after 45 years old are more likely to have children with autism and schizophrenia. At present, scientists have found certain “hot spots” in the genome, where new mutations appear, although the consequences of this are not yet clear.
The results of the study are presented in the scientific publication Nature.
Let’s have a look at overage paternal age. Changing patterns of marriage, education & employment mean that the average age of childbearing for females is increasing, resulting in the highest risks of adverse reproductive outcomes. Scientists in 2019 are suggested that the decade 25–35 years is the optimal age for women, for surrogate programs – the ideal mothers are between ages of 21-35. 2019 stats shows, fathers aged <38 years accounted for 42% of live births within marriage, while 58% of such births were to fathers aged 38–54 years. If this trend continues, the proportion of fathers after 40 years will further increase as well as mutations to their children.