A new study found that nearly three-quarters of mutations in genes that code for proteins occurred fairly recently in the past 5,000 to 10,000 years.
Researchers said that the study, published in the journal Nature, shows that "recent" events have a powerful effect on the human genome, and reveals that the amount of variation or mutation identified in protein-coding genes is very different than the variation that would have been seen 5,000 years ago.
"One of the most interesting points is that Europeans have more new deleterious (potentially disease-causing) mutations than Africans," researcher Dr. Suzanne Leal, professor of molecular and human genetics at Baylor College of Medicine said in a statement.
"Having so many of these new variants can be partially explained by the population explosion in the European population," she said. "However, variation that occur in genes that are involved in Mendelian traits and in those that affect genes essential to the proper functioning of the cell tend to be much older."
Researchers explain that a single gene controls a Mendelian trait and that mutations in that gene can have potentially devastating effects.
86 percent of the genetic variation or mutation researchers found in protein-coding genes that are predicted to be harmful arose in European-Americans in the last five thousand years.
"The recent dramatic increase in human population size, resulting in a deluge of rare functionally important variation, has important implications for understanding and predicting current and future patterns of human disease and evolution," researchers wrote in the study.
For the study, researchers used bioinformatics techniques to calculate the age of more than a million changes in single base pairs (the A-T, C-G of the genetic code) that are part of the exome or protein-coding portion of the genomes of 6,515 European-Americans and African-Americans.