http://www.digitaljournal.com/science/married-couples-have-more-similar-dna/article/384552

Married couples have more similar DNA

Posted May 24, 2014 by Tim Sandle
Married couples have more similar DNA than random pairs of people, according to a new study. n a genetic survey of 825 married couples, researchers found that spouses shared more similar DNA than randomly chosen pairs.
Quang and Ellie s wedding after party.
Quang and Ellie's wedding after party.
Vimeo
Thus the research argues that people tend to gravitate toward similarity at the genetic level. For the study, scientists looked at 1.7 million single nucleotide polymorphisms (SNPs) (that is, a DNA sequence variation) of 1,650 men and women in their 50s, 60s, 70s, or 80s. Compared to the influence of similar educational levels, a well-established determinant of human mate choice, the preference for spouses with a similar genetic composition was about a third as strong.
Benjamin Domingue of the University of Colorado’s Institute of Behavioral Science, said in a research statement: "We do know in some sense that people prefer genetically similar spouses because we know that people tend to date and marry within their own racial and ethnic groups. We worked really hard in this study to not just replicate that fact. We eliminated racial variability and tried to control for ethnic variability. And we still find a preference for genetically similar individuals."
Despite the finding, exactly how people assess and choose mates of similar genetic makeup remains unclear.
The results of the study have been published in the science journal PNAS. The research is titled: "Genetic and educational assortative mating among US adults."