A pair of United States researchers suggested that friends may have the same genomes as a person’s fourth degree cousins.
Published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS), the study revealed that among 2,000 people surveyed, friends may have 0.1% similarity in DNA makeup on average, compared to strangers.
Prof. Nicholas Christakis from Yale University and Prof. James Fowler from the University of California had conducted an analysis of nearly 500,000 single-letter markers across the genetic makeup through the data obtained from Framingham Heary Study.
Other scientists, however, were skeptical about the findings.
“I think that they’re unusual findings, and that usually draws criticisms from scientists,” said Medical Genetics and Political Science Prof. Fowler.
Other researchers expressed skepticism toward the study, saying different factors could affect the results. They were concerned about the ethnicity or other types of “population stratification,” which lead to similar genetic makeup of individuals, most especially of friends.
Prof. Evan Charney from Duke University contested that the conclusion might only work if none of the subjects were related to each other.
“These studies depend upon that assumption – that you’re looking at thousands of people who are not related,” said Charney in a BBC report.