New Genetic Patterns Revealed in Humans: Diverse DNA Mutations

Each person is different, so it shouldn't surprise us that our DNA is also extremely diverse. Scientists, though, have found that DNA might show a bit more diversity than expected. They've found that one person can have several DNA mutations in parts of their body, with their original DNA in the rest, resulting in several different genotypes in one individual. They've also discovered that some of the same genetic mutations occur in unrelated people, altering our very concept of what it means to be human.

Genetic mutations can occur in the cells that are passed on from parent to child and may cause birth defects. Other mutations occur after the egg is fertilized, throughout childhood or even into adult life after people are exposed to environmental factors. These later mutations are called "somatic" mutations and do not affect sperm or egg cells. However, these mutated cells can continue to divide and the person can develop tissue, or a part thereof, with a different DNA sequence from the rest of their body.

"We are in reality diverse beings in that a single person is genetically not a single entity--to be philosophical in ways I do not yet understand--what does it mean to be a person if we are variable within?" said Scott Williams, one of the researchers, in a news release. "We have always thought 'your genome is your genome.' The data suggest that it is not completely true."

In the past, researchers thought each person contains only one DNA sequence. Using the computational power of advanced genetic analysis tools that examine all of the genes in one individual, though, scientists have been able to systematically look for somatic variation. They found that it's possible to have multiple genotypes from mutations within one's own body--a condition that's somewhat analogous to chimerism.

"There is a lot more going on than we thought, and the results are, in some ways, astoundingly weird," said Williams in a news release.

In fact, the researchers found that while somatic changes are thought to happen at random, unrelated people exhibited the same mutations. This, in particular, is an important finding since these mutations are not likely being developed and maintained through purely random processes. Instead, they indicate a completely different model that results in particular mutations in specific tissues.

The findings are published in the journal PLOS Genetics.