WASHINGTON May 19 He leaves the toilet seat up,
prefers old Japanese monster movies to romantic comedies and
fancies mixed martial arts over ballet. So what do you have in
common with your husband?
More than you may think.
People tend to choose spouses who have similar DNA,
according to scientists who reported on Monday the results of a
study exploring the genetic resemblance of married couples.
The researchers examined the genetic blueprints of 825 U.S.
married couples and found a significant preference for a spouse
with DNA similarities across the entire human genome.
The study compared this affinity for husbands or wives with
similar DNA makeup to the well-established and strong tendency
of people to marry mates with similar educational levels. The
researchers found that the preference for a genetically similar
spouse was about a third as strong as the preference for a
spouse with comparable education.
The 1,650 people studied in the research were non-Hispanic,
white men and women born between the 1930s and 1950s who were
taking part in a broader U.S. government-funded study involving
health and retirement.
"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," said
researcher Benjamin Domingue of the University of Colorado's
Institute of Behavioral Science, who led the study.
"We eliminated racial variability and tried to control for
ethnic variability. And we still find a preference for
genetically similar individuals," Domingue added.
The researchers measured genetic similarity by comparing 1.7
million individual DNA building blocks, known as single
nucleotide polymorphisms, in the study participants. They
compared the genetic makeup of the married couples to other
randomly chosen people of the opposite sex in the same pool of
Domingue said the actual mechanism for a person being drawn
to another person's genetic similarities is probably complicated
and multifaceted - "just a whole host of things," he noted.
The researchers noted that people usually pick spouses with
similar backgrounds and characteristics in addition to
education, including race, religion, age, income and body type.
Genetic similarity can be added to the list, they said.
"For example, people clearly care about height in picking
partners. To the extent that tall people marry other tall
people, that is going to result in genetic similarity among
spouses. But it is difficult to know whether height or genes is
driving this decision," Domingue said.
The researchers said it would be interesting to see the
results of similar studies involving other populations including
additional races, interracial spouses and gay couples.
(Reporting by Will Dunham, editing by G Crosse)