consumer genetic testing

The story worth a long read

Grab yourself a cup of coffee, sit down and read the first part of Tina Hesman Saey's sprawling series on consumer genetic testing. It's an epic journey. Maybe you've seen the ads for consumer genetic tests offered by 23andMe or AncestryDNA. Maybe you're one of the millions that have tried the tests for yourself. Well, Tina tried eight. And with a Ph.D. in genetics, she knows a thing or two about understanding the results. Let's just say these companies promise more than they can deliver.

Make sure to check out her detailed review of 23andMe, Veritas Genetics and Genos' tests. And in case that's not enough genetics news for you, read her update on how a controversial genetic technique found a suspect in a cold case.

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Traits that tickle

A lot of what you can learn from consumer genetic testing is more useful for dinner party banter than health decisions. A few favorites:

Photic sneeze reflex — Some people sneeze when they suddenly encounter bright light. At least 54 genetic variants scattered among multiple chromosomes help control the sun-stoked achoo.

Ear fold — How prominent the rim on the outer edge of the ear is depends in part on a variant of the EDAR gene. The gene is important for skin, ear, eye and hair development.

Cilantro preference — Some people like cilantro, others say it tastes soapy. Studies have linked some genetic variants to liking or disliking the herb.

Big toe or not? — Some people have longer second toes than big toes. At least 35 genetic variants, plus the balance of estrogen and testosterone in the womb, help determine toe (and finger) length.

Sweet or salty — Preference for salty or sweet snacks is influenced by at least 43 genetic variants, some located in or near genes involved in brain development.

Asparagus odor in urine — A variant near the OR2M7 gene influences whether people can smell asparagus in their urine after eating the vegetable.

Smelling the roses — Some people can detect a specific rose scent chemical, thanks to an OR5A1receptor gene variant.

ICONS: E. OTWELL

“There will be a time when many more common health conditions will have tests you can do that will really inform you,” says Bryce Mendelsohn, a medical geneticist at the University of California, San Francisco. “But it will be years, years, decades before we’re really at that stage.”