Project start: not started yet

New germline mutations are directly transmitted to our children, and therefore have profound consequences for future generations, but we still know surprisingly little about germline mutation processes. Recent advances in individual genome sequencing showed that the majority of de novo mutations (DNMs) originate in the male germline, and firmly established that the rate of DNMs increases with paternal age. To date, however, we lack information on individual mutagenic events necessary to study a unique type of mutagenesis— the selfish expansion of driver mutations in the male germline— due to the limitations of current technologies in studying DNMs. As a result, only a handful of driver mutations are known and characterized so far. This is unfortunate, as these might represent the tip of an iceberg given that in cancer hundreds of driver mutations are found within single genes. Moreover, they cause congenital disorders, self-propagate, are highly recurrent, and drastically increase with paternal age.

We have adapted a new ultra-sensitive sequencing technology with extremely low error-rates to identify accurately DNMs in selected candidate driver genes in sperm that can then be analyzed by our high-throughput digital PCR method. By combining these technologies, we have, for the first time, the capability to study DNMs in candidate driver genes, and investigate their expansion and increase with paternal age in the male germ line. Using our unique expertise in ultrasensitive methodologies to detect rare mutations, in this project we propose to 1) sequence exons of driver genes to discover high frequency DNMs; 2) test selection by examining the spatial expansion of the discovered DNMs in dissected testes, and 3) analyze their increase and transmission patterns in sperm of differently aged men. We envision that this project will generate a comprehensive and powerful analysis of driver mutations in the male germline, and establish a basis for understanding this type of mutagenesis and the associated risks of delayed parenthood in our society.