Evolution: Research Finds Mutations Continue

Evolution

Medical News Today reports on a finding from the body of a 115-year-old woman who died in 2005, and is said to hold key mutations that could further the investigation into evolution. Her body was donated to science, and now researchers have found that her healthy blood cells were identified as having over 400 genetic mutations. This suggests that evolution could still be in existence as human DNA continues to mutate.  The team was led by Dr. Henne Holstege of  the Dutch VU University Medical Center, and the report was published in the Genome Research Journal.

Mutations are frequently studied in various fields due to their links to various diseases and conditions. Quite little is actually known about the origins and effects of mutations. Stem cells, for instance, are in bone marrow and are constantly dividing. This cell division can introduce errors and produce mutations.

In cases of blood cancer, hundreds of mutations have been recorded, but healthy white blood cells are studied by researchers in order to determine whether or not they actually contain mutations, which could suggest that evolution as a process continues. The researchers conducted a whole-genome sequencing of healthy white blood cells from the donor, and it was found that white blood cells do contain a build-up of mutations.

During her life, the woman did not present with symptoms of hematological illnesses. Upon autopsy, the body did not show signs of vascular or dementia-related pathology.  The researchers discovered over 400 somatic mutations that are not passed to offspring and do not lead to disease. These were found in the white blood cells and were not discovered in the brain. The researchers say that white blood cells within the brain rarely divide after birth. The mutations that were identified were found in non-coding regions of the genome. They were found in mutation-prone areas, but have not been previously linked to disease.

Berkeley.edu describes mutations as the building blocks of evolution. Mutations are the raw material of genetic variation.  Without mutation, there would be no evolution. However, some researchers such as Stephen Jay Gould, an American paleontologist, believe that there had been no signs of evolution for 40,000 to 50,000 years.

In 2013 however, an NPR report was released that discussed a popular paleoanthropologist’s view on evolution. John Hawks says that for the past 10-to 20-thousand years, people have been evolving. Even in the past 50 years alone, Hawks alleges that there are longitudinal differences in the population.

A common change that gets a lot of attention, Hawk says, is lactase persistence. Milk contains a sugar called lactose. Eventually, mammals turn off the enzyme, lactase, as they are weaned from breast milk. In certain populations, there exists a persistence of lactase, which amounts to a genetic change.

Researchers like Hawk and Holstege continue finding links between the continuation of evolution and genetic mutations. Holstege says their study warrants further investigation.

By Lindsey Alexander

Sources:

Medical News Today

Berkeley 

PBS

NPR