Fixing the priority: Twins studies or genome

Despite a consensus on the value of twins studies, there’s disagreement over where research dollars should be focused. Some scientists believe genetically sequencing large numbers of unrelated people — in what are called genome-wide association studies, or GWAs — will result in the next wave of scientific progress.

“Instead of doing another study looking at the heritability of schizophrenia with twins, let’s do a very large GWA study with 250,000 people and identify where it exists in the genome,” says University of North Carolina psychiatrist Patrick Sullivan. “We can get directly into the biology. That’s something twin studies can’t do.”

But John Hopper, an epidemiologist and director of Twins Research Australia begs to differ. He terms the practice of sequencing people by the thousands as a “sledgehammer” approach.

Insights into diseases

Twins add important context about their life experiences that may be missed in these larger studies, he says. For example, to assist an international study based at the University of Southern California, he is recruiting pairs in which one twin has breast cancer and the other doesn’t.

“We’ll be able to fill in the gaps by asking, ‘Who went through puberty first?’” says Hopper. “The magic of studying twins is that you get insights into the causes of disease that you couldn’t get any other way. There’s gold among twins.”