Genetic Ancestry and Parental Smoking Influence New Genetic Mutations in Offspring

Recent research has highlighted that the genetic background and lifestyle choices of parents can impact the rate and type of new genetic mutations introduced in their children. Published in Nature Communications, a collaborative study by the Wellcome Trust Sanger Institute, the University of Cambridge, and other partners analyzed whole-genome sequences from approximately 10,000 parent-child trios. The goal was to understand how factors such as ancestry, genetic variants, and environmental exposures like smoking contribute to de novo mutations (DNMs)—rare genetic changes occurring in sperm or eggs that are transmitted to offspring.

The researchers found that differences in ancestry among populations are associated with slight variations in DNM rates. For example, individuals of African ancestry had an average of about 67 new mutations per generation, while European and South Asian groups had around 64, with the disparities possibly due to genetic or environmental influences. Parental age, especially the age of the father, was identified as a significant factor, with each additional year of paternal age correlating with approximately 1.5 new mutations, compared to 0.4 for maternal age. Interestingly, a 2% increase in mutation count was observed in children of parents with documented histories of smoking. Although the effect size is small, it suggests that smoking might subtly influence the genetic mutation rate.

While it remains unclear whether smoking directly causes these mutations or if it is a marker for other mutagenic exposures, this study underscores that both genetic background and environmental factors play roles in genetic variation. Moreover, these findings could refine models used in population and medical genetics, especially in understanding genetic diseases and evolutionary processes.

Co-senior researchers emphasized that the mutation rate is predominantly driven by parental age, but factors like ancestry and lifestyle choices, including smoking, may exert a minor but meaningful influence. Future studies with larger datasets and detailed environmental data are needed to further explore these associations.

This research advances our understanding of how inherited and environmental factors intertwine to shape human genetic diversity and mutation patterns, paving the way for more precise genetic modeling and disease prediction.