Why did you get the flu this winter, but your co-workers didn’t? The answer, according to a new study of twins, may have less to do with your genes and more to do with your environment—including your past exposure to pathogens and vaccines.
To unravel the competing influences of nature and nurture, researchers led by immunologist Mark Davis of Stanford University in Palo Alto, California, turned to the gold standard test: a twin study. Identical twins are nearly the same genetically, whereas fraternal twins share only about half of their genes. If a trait is hereditary, identical twins will be more likely to share it than fraternal twins, allowing scientists to tease out the genetic component.
After recruiting 210 identical and fraternal twins between 8 and 82 years old, Davis and colleagues took blood samples and measured more than 200 parameters of their immune systems. For example, they measured the numbers of 95 kinds of immune cells and 51 kinds of proteins. Today, the researchers report online in Cell that identical twins’ immune systems were too different for the variation to boil down to genetics.
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Read full, original story: Environment, more than genetics, shapes immune system
