2018/02/08

DNA is not your destiny

DNA genes don't determine traits - Why mapping your DNA may be less reliable than you think

https://www.theglobeandmail.com/technology/science/genetic-testing/article37829424/

Excerpt: "Yet, the more genomes researchers study, the more evidence mounts that using DNA to predict health risks is anything but precise – for now, at least. These days, nature's longest thread comes off a like a trickster, shape-shifting from person to person, written in a wily language no one fully understands, with at least three billion ways to misread it.

Launched publicly in Canada in 2012, the PGP aims to build an open, online database of Canadian genomes for use by researchers anywhere and more than 1,100 Canadians have signed up so far. But by unravelling the entire codes of just the inaugural participants, what the project leaders have found is both promising and perplexing: medically relevant information in each volunteer, but also a vast trove of mysterious quirks and dramatic glitches that none of them expected to see in a cohort of healthy people.

Surprising, too, is that many of the volunteers carry mutated genes that suggest they should be sick, diseased or even near death – but aren't.

Take Participant No. 16, whose genes seem to tell the grim story of an aortic stenosis. The potentially lethal heart defect develops before birth, narrowing the body's main artery just above the valve that connects it to the heart, forcing it to work harder, which can lead to chest pains, heart failure and the risk of sudden death. On paper, No. 16 looks like a time bomb. In real life, he is a healthy 67-year-old who works long hours, skis, trains with CrossFit three times a week and, according to a CT scan, has a normal heart.
 
Participant No. 27 is another jolt. Missing from about 70 per cent of her blood cells is an entire chromosome, the X sex chromosome, of which women usually have two copies. On paper, No. 27 has mosaic Turner syndrome, a rare disorder that only affects females and can lead to impaired sexual development, short stature, a webbed neck and heart problems. In reality, she is a healthy 54-year-old who had no inkling her DNA harboured such a twist.

The report, compiled by 53 researchers at the Hospital for Sick Children and the University of Toronto, captures the staggering breadth of how much is left to learn before science can properly interpret humanity's operating code. It offers proof that most research to date has overlooked the different types of genetic glitches that can lead to health problems, while adding to the growing realization that many genes once thought to cause disease probably don't.

Just ask Participant No. 16 about the heart abnormalities his genes suggest.

You can imagine someone getting this report back and saying, 'Oh my God, I'm gonna die of this! How do I check it out?' Then there will be echocardiograms and all these things being done on people who are perfectly healthy," says Doug Mowbray, who wasn't troubled by his vexing results because the participants had a genetic counsellor walk them through the fog. But also because he's a doctor himself – a radiologist, in fact, in Southwestern Ontario. He knew his heart was normal because he took a good look at it while calibrating a new imaging scanner a few years ago.

All of which implies that in these foggy days of the so-called genomic revolution, people can easily be led astray by test results that may bring false comfort, or needless stress and treatment – especially now, when the largely unregulated market of direct-to-consumer DNA tests is booming."

My comment: The DNA genes don't determine traits. There are no skin color, height, intelligence, obesity or any other trait that is directly connected to a certain gene. The ‘grammar’ of the human genetic code is more complex than that of even the most intricately constructed spoken languages in the world. There are only ~19,600 DNA genes used for protein encoding machineries in our DNA, but the number of different protein isoforms in our bodies might be up to one million. Mutations in these overlapping and embedded genes are typically very harmful. The DNA is a library that cells use for managing their tasks.

Traits are determined by our epigenome. This covers the DNA methylation profiles, a huge diversity of histone chemical tags (a biological database) and different types of coding and non-coding RNA-molecules that function as epigenetic information carriers between cells.

Life is not driven by the DNA genes. Genes are driven by your lifestyle. Genes are followers, not leaders. That's why the theory of evolution is the most serious heresy of our time. Don't get lost.