How Kids See the World Depends a Lot on Genetics

Baby in eye gaze study

Caption: Child watches video while researchers track his eye movements.
Credit: Washington University School of Medicine, St. Louis

From the time we are born, most of us humans closely watch the world around us, paying special attention to people’s faces and expressions. Now, for the first time, an NIH-funded team has shown that the ways in which children look at faces and many other things are strongly influenced by the genes they’ve inherited from their parents.

The findings come from experiments that tracked the eye movements of toddlers watching videos of other kids or adult caregivers. The experiments showed that identical twins—who share the same genes and the same home environment—spend almost precisely the same proportion of time looking at faces, even when watching different videos. And when identical twins watched the same video, they tended to look at the same thing at almost exactly the same time! In contrast, fraternal twins—who shared the same home environment, but, on average, shared just half of their genes—had patterns of eye movement that were far less similar.

Interestingly, the researchers also found that the visual behaviors most affected in children with autism spectrum disorder (ASD)—attention to another person’s eyes and mouth—were those that also appeared to be the most heavily influenced by genetics. The discovery makes an important connection between two well-known features of ASD: a strong hereditary component and poor eye contact with other people.

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Random Mutations Play Major Role in Cancer

Cancer OddsWe humans are wired to search for a causative agent when something bad happens. When someone develops cancer, we seek a reason. Maybe cancer runs in the family. Or perhaps the person smoked, never wore sunscreen, or drank too much alcohol. At some level, those are reasonable assumptions, as genes, lifestyle, and environment do play important roles in cancer. But a new study claims that the reason why many people get cancer is simply just bad luck.

This bad luck occurs during the normal process of cell division that is essential to helping our bodies grow and remain healthy. Every time a cell divides, its 6 billion letters of DNA are copied, with a new copy going to each daughter cell. Typos inevitably occur during this duplication process, and the cell’s DNA proofreading mechanisms usually catch and correct these typos. However, every once in a while, a typo slips through—and if that misspelling happens to occur in certain key areas of the genome, it can drive a cell onto a pathway of uncontrolled growth that leads to cancer. In fact, according to a team of NIH-funded researchers, nearly two-thirds of DNA typos in human cancers arise in this random way.

The latest findings should help to reassure people being treated for many forms of cancer that they likely couldn’t have prevented their illness. They also serve as an important reminder that, in addition to working on better strategies for prevention, cancer researchers must continue to pursue innovative technologies for early detection and treatment.

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