On Sept. 20, 2017, resarchers at deCODE genetics use whole-genome data from 14,000 people from across the population of Iceland, including 1500 sets of parents and children, to provide the most detailed portrait to date of how sequence diversity in humans is the result of an evolving interaction between sex, age, mutation type and location in the genome. “Parental influence on human germline de novo mutations in 1,548 trios from Iceland” was published in the online edition of Nature.

The study shows that in about 10% of the genome, the de novo mutations coming from the mother equal in number the ones coming from the father. Most of the maternally derived de novo mutations in these regions are C-to-G (C>G) mutations and are rooted in flaws in the repair of double-strand breaks. The density of C>G SNPs in this 10% of the genome is also very high, with considerable variability in the frequency of the less common allele. This indicates that these regions of the genome have been vulnerable to double-strand breaks for a very long time. These same regions of the genome also show a high density of C>G SNPs in chimpanzees, less so in gorillas, and not at all in orangutans.

This study leverages deCODE’s unique genetics resources in Iceland to build upon earlier results linking parental age and sex to variability in recombination and various types of mutation. De novo mutations are so called because they are generated during the formation of eggs and sperm, they can be passed to offspring but are not seen in the parents. The deCODE team was able to develop such a large dataset and catalogue of these mutations correlating whole-genome sequence data from thousands of individuals and multiple generations of families with information on the age of parents at the time their children were born.