#CBC: « SECOND OPINION | Your life is leaving genetic scars that might show up in your child’s genes – Health »
Hello and happy Saturday! Here’s our summer roundup of eclectic and under-the-radar health and medical science news.
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Scientists now know that the mere act of living leaves molecular scars on our genes.
But it was long assumed that those marks were wiped clean when the genes were passed on to the next generation.
Not so, according to research in the mysterious field of epigenetics. And a new paper shows some of the first evidence of how offspring are affected.
« It was assumed there was zero transmission of epigenetic information from one generation to another, McGill University pharmacology professor Moshe Szyf told us. « This paper adds to that body of evidence showing that assumption is not true. »
Epigenetics is an emerging field of research proving once again that DNA is complicated. It won’t work without a second layer of genetic activity called epigenetics, a series of biochemical processes that translate DNA’s genetic information into cellular mechanisms in the human body.
And the way those epigenetic programs turn certain genes up or down, on or off can be affected by what we eat, and how we live, how much stress we experience, or what toxic exposures we have.
« The big question is how much the experiences we are going through, including trauma, disease or famine, etc. is passed to the next generation, » said Szyf.
The study published in Science shows evidence that fruit fly offspring inherit a specific epigenetic change critical to the embryo’s development. But what do humans have in common with fruit flies? A lot.
‘We were under the illusion that if we know genetics we understand everything about life.’
– Moshe Szyf
« Evolution has taught us that principles that work in one organism usually work in many organisms. And if a basic process appears in a fruit fly, it usually also appears in humans, » Szyf said.
The first clues to epigenetic heritability came from curious observations following a series of famine cycles in a northern province of Sweden in the early 1800s. Scientists linked changes in life expectancy to grandparents’ exposure to feast or famine.
Other observations made after the Dutch famine during the Second World War showed persistent changes in DNA expression six decades later, adding to evidence that life experiences can leave permanent marks on our genes.
« We were under the illusion that if we know genetics we understand everything about life, » Szyf said. « Epigenetic information is much more dynamic and responsive to the environment. And it raises the possibility that experience can be passed from one generation to the next. And that’s the allure of this whole thing. »
Opening the black box of peer review
Imagine having all of your colleagues and all of your competitors looking over your shoulder at everything you do. And now imagine them pointing out everything you did wrong and sending you back to do it all over again.
That’s the basic premise of scientific peer review. Before a research paper is published in a scientific journal, several scientists examine the work to determine if the methods are sound and the conclusions are supported by the data. It’s a much-heralded pillar of the scientific process.
But the irony of peer review is that the process itself is never peer reviewed. David Moher, a senior scientist at the Ottawa Hospital Research Institute, called for the « black box » of peer review to be opened, in a commentary he co-authored in Science.
‘I don’t want to trash journals. I want to make them better.’
– David Moher
« We have very little evidence that peer review works, » Moher told us, pointing to the rise of predatory journals as evidence of the urgent need to improve peer review.
Predatory journals disguise themselves as legitimate scientific publications and make money by charging scientists for publishing their papers. There is evidence of these journals accepting scientific gibberish and appointing people who don’t even exist to their editorial boards. (Read about Dr. Fraud in our March 26 newsletter.)
« If journals do not get a handle on peer review, then they can’t distinguish themselves from these predatory journals, » Moher said.
Ivan Oransky and Adam Marcus are watchdogs who track retractions of scientific papers on their blog Retraction Watch. They compared the current system of peer review to a toothless guard dog, incapable of spotting fraud or plagiarism, or keeping bad science from polluting the scientific record.
« There’s a tremendous movement to open science, » Moher said, calling on publishers to open their doors and allow scientists to study their peer review process. « I don’t want to trash journals. I want to make them better. »
A Canadian moment in medical history
As part of our summer Second Opinion series, we’re featuring great Canadian moments in medical history. This week meet Charles Beer and Robert Noble.
Together they discovered a chemotherapy drug in a Jamaican periwinkle plant that arrived in the mail.
It was an accidental discovery. They weren’t looking for anti-cancer agents. Instead, the two researchers at the University of Western Ontario (now Western University) were searching for diabetes drugs. And they were curious what magic might be found in the periwinkle sample that had been mailed to Noble’s brother.
« The disease of cancer was certainly far from our thoughts when we learned of a tea made from the leaves of a West Indian shrub that was supposedly useful in the control of diabetes mellitus, » they wrote in their 1958 paper « Role of Chance Observations in Chemotherapy: Vinca Rosea. »
Beer was an expert chemist, and he knew how to extract the plant’s key compound. But when those extracts were fed to diabetic rabbits nothing happened. The blood sugar levels didn’t change. But when they injected the extract into the rabbits’ veins, the animals quickly died from a bacterial infection. « Apparently some natural barrier to infection was being depressed, » they wrote.
They soon realized the periwinkle compound lowered the levels of white blood cells and depressed bone marrow. Could this be a possible treatment for leukemia, caused when white blood cells proliferate out of control?
They started growing the plant nearby so they could have a steady supply of the extract, even though in the Canadian climate the plants expressed much less of the active ingredient. Once they could reliably extract the compound they tested it on cancer patients at Princess Margaret Hospital in Toronto. That was almost 60 years ago.
Today vinblastine is on the World Health Organization’s list of essential medicines, used in combination with other drugs on lymphoma and other cancers.
Beer died in 2010 at age 95. Noble died in 1990 at age 80.
These fascinating stories of discovery were selected from the Canadian Medical Hall of Fame, a medical history organization that began in 1994. Every year, six Canadians are inducted. There is a small exhibit hall in London, Ont., but executive director Lissa Foster told us the real hall lives online, with video features for the 125 laureates.
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Note: « Previously Published on: 19 August 2017 | 12:00 pm, as ‘SECOND OPINION | Your life is leaving genetic scars that might show up in your child’s genes – Health’ on CBC RADIO-CANADA. Here is a source link for the Article’s Image(s) and Content ».