Until now, de novo genetic mutations, alterations in a gene found for the first time in one family member, were believed to be mainly the result of new mutations in the sperm or eggs (germline) of one of the parents and passed on to their child.
Researchers from The Netherlands have now succeeded in determining that at least 6.5% of de novo mutations occur during the development of the child (post-zygotic) rather than from the germline of a parent. The research is published today in the American Journal of Human Genetics*.