One night last month, on my way from Penn Station to Brooklyn, I came across two very different types of New York talent. I didn’t think it was possible, but these two made me love my city just a little bit more. Enjoy.
Researchers from Signature Genomics, a private clinical genetic testing company in Spokane, Washington, have found, for instance, that many children with autism inherit deletions in the 16p11.2 chromosomal region — famously linked to autism — from healthy parents with no sign of the disorder.
The findings debunk previous hype that any one variant is crucial for a particular disorder, the researchers say.
Everyone knows the shape of DNA: the iconic, graceful figure-8s of the double helix. If that ladder weren’t folded into some tight, three-dimensional structure, then the code for every cell in our body would be six feet long! Obviously, that just wouldn’t do.
Until recently, scientists had assumed that DNA folds into a sphere that looks like a tangled ball of yarn (above left). With this arrangement, it would be possible for genes that are close together on the ladder to actually be quite distant in 3D space. But last month, a team of researchers from Massachusetts — including Eric Lander, one of the leaders of the Human Genome Project, and now one of Obama’s lead science advisers — reported in Science that the structure is actually much more smartly organized (above right). From the MIT news office:
This architecture, called a “fractal globule,” enables the cell to pack DNA incredibly tightly while avoiding the knots and tangles that might interfere with the cell’s ability to read its own genome. Moreover, the DNA can easily unfold and refold during gene activation, gene repression and cell replication.
“Nature’s devised a stunningly elegant solution to storing information — a super-dense, knot-free structure,” says senior author Eric Lander, director of the Broad Institute, who is also professor of biology at MIT and professor of systems biology at Harvard Medical School.
For a lot more info about how this work was done, check out Science’s podcast interview with first author Job Dekker, of UMass.
One of the many perks of working from home is having time to bake. Not only are these Halloween treats adorable, but they’re made with Nutella!
I used Giada’s ‘Chocolate Hazelnut Smooches’ recipe, with one modification: It calls for orange sugar, which I couldn’t find anywhere. So I rolled the cookies in shaved pieces of dried papaya instead. Below the fold are directions and more photos. Enjoy!
“The plan is to put me inside the fMRI scanner, apply burning heat, and see whether I can train myself to regulate my pain.”
That’s from reporter Erik Vance, who recently visited the lab of Stanford neurologist Sean Mackey. In a new feature for Nature, Vance describes Mackey’s research through the lens of being an actual participant (fair warning, this is uncomfortable to read):
Inside the coffin-sized tube of the fMRI machine, spasms in my back from its powerful magnet distract from the burning plate strapped again to my arm. On a screen above, I can see a squiggly line that represents the activity in a part of my anterior cingulate cortex. Mackey asks that I envision the heat as alternately searing and soothing. The aim is to master control of the line so that it (and thus my pain) goes up and down. As I switch between these visions the line on the screen twitches up and down.
It is surprisingly difficult. Willpower and meditation have little effect, and after two hours it is increasingly hard to make the stubborn little line move at all.
In this case, I think Vance’s first-person account is remarkably effective way to tell the story. Pain is fundamentally experiential, after all.
It seems like I’m hearing more and more about journalists who put themselves through odd or unpleasant situations for the sake of a story. Ted Conover became a guard at Sing Sing to find out what prison life is really like. Slate’s Emily Yoffe, aka The Human Guinea Pig, has for six years written firsthand accounts, such as what it’s like to: be a daycare worker, a member of the Washington Nationals grounds crew, or compete in a matzo-ball eating competition.
As On the Media pointed out last year during an interview with Conover, this approach is usually extremely popular with readers. But when is going undercover unethical? Or worse — when does it become a gimmick?
A pathway involved in language development is increasingly proving to be important in autism, suggest a series of new studies on cellular and behavioral aspects of the disorder.
Reports published in the last year, as well as preliminary data revealed last week at the Society for Neuroscience meeting in Chicago add heft to the idea that the pathway may cause the language and other problems associated with autism.
In 1990, a letter to Nature described a large, three-generation family from London whose members had severe and distinct deficits in applying grammatical rules, and suggested “one dominant gene” as the cause. A decade later, geneticists screening the family pinpointed a gene — FOXP2, on chromosome 7 — that is mutated in family members with language impairment.
FOXP2 codes for a protein that regulates the expression of other genes. Last year, an international group of scientists identified one of its targets, contactin-associated protein-like 2 (CNTNAP2). They also found that certain common variants of CNTNAP2 tend to crop up in people with specific language impairment, a developmental disorder.
CNTNAP2 was an exciting find because three independent teams had recently published that common variants of the gene up the risk of developing autism.
“I think the evidence now that CNTNAP2 is involved [in autism] is quite good,” says leader of one of the teams, Aravinda Chakravarti, professor at the McKusick Nathans Institute of Genetic Medicine at Johns Hopkins University. “We’re now interested in finding the molecular basis of this.”
After my fun week in Chicago at the Society for Neuroscience conference, I’m now trying to catch up on tweets and blog posts I missed from the American Society of Human Genetics meeting, in Honolulu.
Nature News’s conference blog has an interesting post reporting one of the first surveys of what kind of people are interested in getting genetic testing — and how their results affect their future health care decisions. The ‘Multiplex Initiative‘ is asking 1,000 healthy adults from a the Henry Ford Health System, in Detroit, whether they’d like to be screened for variants in 15 genes that relate to common diseases, such as diabetes, heart disease, and lung cancer.
From the Nature post, here’s what the researchers are finding so far about which people choose to get the tests (emphasis mine):
…one of the strongest factors that predicts which patients choose to take the multiplex test was how much the patient believed that behavior contributes to overall risk of disease. Those who believed more strongly that behavior contributes to disease – that smoking, not just genetic makeup, affects the risk of lung cancer, for example – were more likely to get tested. McBride’s interpreted this finding to mean that the patients wouldn’t believe that they were powerless to do anything about their disease risk if they got a “high risk” test result. And, conversely, they might be more motivated to change their behavior by a multiplex test result.
And Robert Reid of Group Health Cooperative in Seattle said that patients who took the multiplex test made slightly more visits to their primary care doctors in the 18 months after getting their test results than they had in the 18 months prior to taking the test. But even though the increase was significant, it was still a small increase in sheer number of visits. What’s more, the number of screening tests ordered on the patients didn’t increase after the genetic tests were completed.
That seemed like good news to me. It could mean that these people are actually discussing with their docs what the results could mean, and how their lifestyle could affect their risk…right? Right?!
Wrong. The survey found that only 11 percent of the people who got tested discussed the findings with their docs (and 14 percent planned to discuss them). Reid counted that as good news, indicating that the patients weren’t overreacting and spurring unnecessary (and costly) diagnostic tests. I think that’s overly optimistic.
What’s happening, it seems, is that genetic testing makes people think more about their health (and thus, going to the doctor more). But what good are these extra visits if the docs aren’t being asked to help interpret the results? Do the patients figure that their doctor wouldn’t know much about genetics, anyway? Are they right?
Because these defects are seen during a critical period of learning, they could prevent developing brain cells from linking up to appropriate brain circuits, says lead investigator Carlos Portera-Cailliau, assistant professor of neurology and neurobiology at the University of California in Los Angeles. “This presumably has serious consequences for the ability of these mice to learn,” he says.
The researchers studied the gene expression profiles of five brains and found two distinct types: one that preferentially expresses genes controlling immune regulation, and another expressing those related to changes at synapses, the junctions between neurons.
Intriguingly, few genes are over-expressed in both types of brains as compared with healthy controls, which may speak to the heterogeneity of the disorder, says lead investigator John Allman, professor of biology at the California Institute of Technology. “There may be several routes to autism.”
Over at Tech Review’s website, ScienceBlogger Mo Costandi has an amazing photo essay showing how brain imaging technology has progressed since Santiago Ramón y Cajal’s exquisite drawings of the late 19th century. A must-read for brain buffs!
