Genetic Maps of African Americans

Genetic map shows genetic mutation sites

(RxWiki News) Certain congenital diseases such as sickle cell anemia predominantly affect blacks. The University of Oxford constructed the first detailed genetic map from African American genetic information that may allow for better treatment of such diseases.

It is significantly different than those previously created from people with European ancestry, and is expected to aid research in congenital diseases that affect blacks. Such research may eventually allow doctors to better treat congenital diseases.

"Ask a geneticist if you should take a DNA test."

Simon Myers, study co-leader and a lecturer in the department of statistics at the University of Oxford, said that more than half of African Americans carry a version of recombination that is different from Europeans. A genetic map identifies the precise area in the genetic material of a sperm or egg where parental DNA is reshuffled to produce a single reproductive cell, also called recombination.

It has been just recently that scientists have begun to examine genetic differences, and their role in human health. The genetic map is a crucial tool in identifying those differences based on where recombination has occurred across a genome. Recombination, along with mutation, accounts for variety among species.

Mutation is the result of errors that happen when cells divide, while recombination is the process by which large chunks of chromosomes are stitched together during sexual reproduction. The stitching only occurs at certain locations.

Researchers previously discovered a DNA code, or motif, that attracted part of the recombination machinery, a gene called PRDM9. Knowing this string of 13 DNA letters, there were able to focus on recombination hotspots.

When recombination goes wrong it can result in mutations that cause congenital diseases such as Charcot-Marie-Tooth disease and certain anemias.

However, investigators found that the DNA code responsible for most European hotspots, accounted for only two thirds as much recombination in blacks. The remaining third was linked to a new motif of 17 base players, recognized as a version that occurs almost exclusively in blacks.

The findings may help researchers understand the roots of congenital conditions that most often occur in African Americans, and also with the discovery of new disease genes among all populations.

The study, which had 81 co-authors, utilized DNA samples from five large studies used to study common condition such as heart disease and cancer.

The findings were published in journal Nature.

Review Date: 
July 27, 2011