Finding gene activity differences in identical twins

Ars Technica » Scientific Method 2015-01-10

They're called identical twins because their genomes are identical. But even though all of their DNA is the same, they clearly are not. The environment must play a role in how identical twins—and everyone else—uses their genes to become who they are.

Until recently, laboratory techniques have not been sensitive enough to detect how, and to what extent, environmental effects dictate the activity of genes. Now that we have the ability to do so, studies are examining variations in the activity of genes in identical twins to try to start unraveling the relative contributions of genetic and environmental effects.

Everybody has two copies of each gene; one from our mother and one from our father. Each of these is called an allele. DNA and RNA sequencing technologies have advanced to the point where allele-specific expression can now be quantified. In other words, we can see, within one individual, if the mom's gene is producing more or less than the dad's version. Allele-specific expression levels of a given gene may differ between individuals even if the total activity of that gene does not.

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