Duplicate studies

    A registry of twins will let researchers look deeper into what factors influence our health and behaviour

    By Lewis Kelly on August 6, 2019


    Photo by George Marks / Getty Images

    Yao Zheng likes it when he sees double. A Faculty of Arts researcher focusing on human development, he says studying twins offers insight into everything from the development of cancer to the heritability of mental illness. “When we study humans, there’s no way to control for everything,” he says. “But twins offer a quasi-natural experiment and help us understand how genes and environment shape us.”

    To delve deeper, Zheng is in the process of launching the Alberta Twin Registry, the opening date of which is to be determined. He hopes to convince thousands of Alberta twins to participate, which would make it one of just three twin research registries in Canada — and the largest by far. (Research from the other two is scant, he says.) It will require persuading lots of twins to participate in regular surveys, following them for years to develop broad-based, meaningful studies. Zheng himself plans a study into anti‑social behaviour.

    You can put almost everything that influences a person’s health into three buckets, Zheng says. First is our genes — our heritage from our biological parents. Second is our shared environment — the external factors that influence a study’s subjects. If you were studying, say, lumberjacks, then wearing flannel and felling trees would be part of their shared environment. The third bucket is the non-shared environment, stuff that doesn’t fit in the other two. The passion fruit protein shake one lumberjack downs daily? Part of his third bucket.

    Since twins share half or all their genes and much of their home environment, researchers can control for the first two buckets. They can use large-scale twin studies to arrive at the holy grail of population health research: cause-and-effect findings. The Alberta Twin Registry would be a major step toward making that happen.