CHOP's Genome Center Helps Build Advanced Genetic Map, Based on African American DNA


The Center for Applied Genomics at CHOP played an important role in a large international research consortium that just created the world’s most advanced genetic map, published July 20 in the journal Nature.

The Center contributed high-density genotypes form nearly 80,000 samples of DNA collected through the Children’s Hospital pediatric network from healthy African American control subjects--children and adults.

Those samples provided important data to the collaboration among numerous researchers from dozens of institutions, led by Dr. David Reich from Harvard University and Dr. Simon Myers of Oxford University in the U.K. The new biological atlas is expected to help scientists better understand the genetic origins of inherited conditions that occur at higher rates in African Americans, as well as assisting the discovery of disease-causing mutations in all human populations.

Hakon Hakonarson, M.D., Ph.D., director of CHOP’s Center for Applied Genomics, and a co-author of the paper, entitled “The landscape of recombination in African Americans,” said “The DNA samples from our biobank played a crucial role in enabling the genetic map, setting the stage for important scientific discoveries in the future.”

Dr. Hakonarson, who was also involved in the initial design of the study, added that since African American populations have an average of 80 percent West African ancestral genes and 20 percent European ancestral genes, they provide valuable resources in helping scientists discern patterns in human genetic variation.

The shuffling of genes from both parents that occurs during conception is called recombination, and some sites along chromosomes are more likely to recombine than other sites. The current study identified 2,500 “hotspots” for recombination that tend to be much more common and involve smaller stretches of DNA in people of West African ancestry, such as African Americans, than in Europeans.

Because errors in recombination may result in disease-causing mutations, these recombination hotspots are more likely to contain mutations responsible for diseases with higher rates among African Americans. A previous scientific study recently showed that the majority of genome research has occurred in people of European ancestry, so this new map provides a contrasting population, with broader opportunities to investigate genetic origins of diseases.

For more details, see this press release from Harvard: