A medical team was ready for me when I arrived: a genetic counsellor, a researcher, two doctors. (It was in the midst of the SARS outbreak, and it didn’t help that everyone sounded like Darth Vader from behind their face masks.) They had found a problem with one of my 46 chromosomes, they said – No. 11. It was inverted.
Inverted, I asked, as in upside down?
Inverted, they repeated – not the whole chromosome, but a good chunk of it.
Was it hanging like a bat in my cells, I wondered, or was it more like a Led Zeppelin track, playing backward and saying something sinister?
It was rare, they told me, to see such a thing – and troubling. Chromosome 11 is no genomic idler – it is tied to personality, with receptor genes linked to mood, pleasure and movement. So what did it mean that mine was belly-up?
“It may mean your entire genome is unstable,” they said. “These inversions are known to cause problems.”
They gave me a package of medical literature on chromosomal inversions and offered to scan my unborn child for the same anomaly – in case it led to doubts about continuing my pregnancy. It did, but I never did go for that scan.
Two years later, after the birth of a healthy child, I was still trying to make sense of my upside-down 11. Dr. Scherer invited me to a meeting of international scientists who were in town to discuss “structural variation in the human genome.”
A parade of researchers took to the podium, describing the quirks they were spotting in the genomes of perfectly healthy folks: swaths of deleted code, hundreds of thousands of extra bits, chromosome pairs that did not match, and inverted chromosomes of all sorts, inside out and backward.
“What the heck is normal?” one of the experts joked. Most agreed they could not know without a grand stockpile of genomes to reference. People were making critical medical decisions with only half the story.
Seven years later, that’s still true. Even in Dr. Scherer’s own lab, where he and his team are focused on solving the genetic mystery of autism, it can be tricky to tell when they have spotted a meaningful mutation – there are too few control genomes for comparison. Recently, he had no choice but to use his own DNA as a control.
“It’s a big problem for any genetic study,” he says – and worse for anyone studying patients from non-European ancestry, for whom control data are virtually non-existent. Genomes can vary dramatically between ethnic groups, but without a large bank of data drawn from different populations, researchers cannot tell what is common and what isn’t.
Elise Heon, ophthalmologist-in-chief at the Hospital for Sick Children, faced this challenge in 2009, when she was facing a tight deadline to place a Tamil patient in a promising gene-therapy trial. Dr. Heon had discovered a gene mutation in the girl, who had a retinal disorder that had left her legally blind, but she had no way of knowing if it was the cause of the girl’s disease or simply a variant common in Tamil people. Dr. Heon’s only hope was to find other Tamils, and collect samples from them quickly.
As it happened, Tamil protesters had gathered outside the U.S. consulate down the road from the hospital. Dr. Heon and a handful of other researchers packed spit kits and consent forms and headed to the protest to collect DNA samples that could be used as controls.
The mutation turned out to be the culprit, and the Tamil girl gained access to the trial, which improved her sight, and enabled her to walk without a cane.
Privacy is a relatively young concept, born with the rise of cities, George Church argues. For most of human history, everyone lived in villages, and extended families in homes without doors, and everyone knew everyone’s business.
Dr. Church is the lanky, 58-year-old Harvard University genetics professor and entrepreneur who created the U.S. version of the Personal Genome Project in 2005. He is on a mission to change global perceptions of genetic information.Report Typo/Error
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