Parents Transmit Up to 60 Mutations to Their Children

In an analysis that encompassed the entire human genome, geneticists were finally able to measure the amount of mutations mothers and fathers pass to their children. In this first-of-its-kind investigation, the team found that up to 60 mutations are passed from one generation to the next.

Studying these mutations is critically important for understanding the direction in which our species is heading evolutionarily. These changes are the primary source of variation, one of the leading engines of evolution in all existing species.

Mutations can for example aid a new generation resist some challenges that the previous generation was unable to cope with. This has been evidenced many times over in studies of microorganisms such as bacteria, which go through many generations in a time frame that is not prohibitively long.

The new investigation was carried out by studying two families. Whole genome sequences from the 1000 Genomes Project were also used to augment the validity of the results. Experts found mutations in children that were not obvious in their parents.

However, discovering these mutations is tremendously difficult, taking into account the fact that only 1 in 100 million DNA “letters” change. In past investigations, researchers only looked at how mutations occur over several generations, and across both genders.

“We human geneticists have theorized that mutation rates might be different between the sexes or between people. We know now that, in some families, most mutations might arise from the mother, in others most will arise from the father,” says Dr. Matt Hurles.

“This is a surprise: many people expected that in all families most mutations would come from the father, due to the additional number of times that the genome needs to be copied to make a sperm, as opposed to an egg,” he adds.

Hurles, who holds an appointment as a senior group leader at the Wellcome Trust Sanger Institute, in the United Kingdom, is a co-leader of the research. Experts from Montreal, Canada and Boston, the United States, were also involved in the work, Daily Galaxy reports.

“Today, we have been able to test previous theories through new developments in experimental technologies and our analytical algorithms,” explains project co-leader Philip Awadalla, a professor a the University of Montreal.

“This has allowed us to find these new mutations, which are like very small needles in a very large haystack,” he goes on to say.