Down's syndrome happens when a human being ends up with an extra copy of chromosome 21 — three copies, instead of the normal two. But scientists say they might have found a way to make that extra chromosome functionally irrelevant. If they're right, it could lead to treatments that could someday reduce the symptoms of Down's. The trick is connected to another extra chromosome that the human body "turns off" all the time — the X. Women have two X chromosomes, of course, but only one ever gets to express itself
. Scientists put the same mechanism to use on chromosome 21
in petri dish experiments. Read the rest
Nine people who have not recently made any sweeping judgements about biotechnology.
Last week, I told you about the US Supreme Court ruling that made it illegal to patent naturally occurring DNA. In that article, I talked briefly about the fact that the new ruling doesn't cover all DNA. It's still perfectly legal to patent synthetic DNA, and the court documents referred specifically to complementary DNA (aka cDNA).
This is where things get murky. Complementary DNA is a thing that can be both natural and synthetic. And, as a laboratory creation, it's an important step in a common method of replicating naturally occurring DNA. All of which leaves some holes in the idea that the Supreme Court ruling is a simple "win" for open-access science, patent activists, and patients. After all, if you can't patent a gene, but you can patent the laboratory copy of the gene, what's that mean? It's sort of like not being able to patent a novel, but being able to patent a copy of its contents that's had all the white space removed. It seems like everybody is a bit confused by this. So I wanted to take a moment to at least clarify what cDNA is and what some people, on different sides of the science/law/biotech divides, are thinking about it.
It starts with some stuff you learned back in junior high — how information from your DNA gets turned into actual working proteins. Read the rest
History has shown us that even some of the greatest scientific luminaries, towering figures such as the naturalist Charles Darwin, the twice-Nobel-Laureate chemist Linus Pauling, and the embodiment of genius — Albert Einstein — have made some serious blunders.
In an unanimous decision, the United States Supreme Court ruled today that companies can't patent genes, or parts of genes — at least, so long as that genetic material is identical to what occurs in nature. The lawsuit dealt specifically with Myriad Genetics, the company that isolated and has claimed a patent on BRCA 1 and BRCA 2 — genes associated with an increased risk of breast and ovarian cancers. From a practical perspective, Myriad's hold on the genes has meant that tests for genetic cancer risk are strikingly expensive — Xeni paid more than $3000 for hers. It's also meant that, if you get a positive result, there's been nowhere you could go for a second opinion.
That's a big deal. Mutations in the BRCA 1 and 2 genes mean an increased risk of cancer, but there's more than one kind of mutation that can happen. In fact, BRCA 1, alone, has hundreds of known mutations. Some increase your risk of cancer. But, even if you narrow it down to just those, they don't all increase the risk by the same amount. The health choices you make could be very different depending on whether you have an 80% risk of developing breast cancer by age 90 (the worst-case scenario for BRCA 1 mutations), or something much lower. That's the kind of situation where you might really like to have more than one lab run more than one kind of test.
This ruling opens the door for that, and the competition should (theoretically) also lower the cost. Read the rest
Genetically speaking, identical twins ought to be two copies of the same person. Environmentally speaking, if the twins grow up together, they ought to even be influenced by the same things. But if you actually pay attention to identical twins, they aren't identical in personality or interests. How do naturally occurring clones become individual people?
That's the subject of a mouse study that Scicurious writes about on her blog. Fascinating stuff. Read the rest
Short answer: We don't know
. What makes this story by Erin Wayman interesting is the way it carefully breaks down an almost Hollywood-ready narrative and finds the fascinating uncertainty lurking underneath. The truth is, uncertainty is cool. Because it means there's more stuff left to discover. Read the rest
The coelacanth is one of a small handful of living fishes that are probably closely related much more ancient, extinct creatures — including, the first fish to haul itself up onto land. Now scientists have sequenced its genes and are digging through the data in search of genetic clues to how fish and land-dwelling animals are connected to one another
. Among the finds so far, a gene that seems to be connected to how animals grow placentas. Coelacanths don't have placentas, but they do have eggs that hatch inside their own bodies. Read the rest
Thanks to Jurassic Park, we tend to focus on one use for the DNA of extinct creatures — resurrecting them, in full, to live here in the modern age. But it's not necessary to go that far to learn a lot about those animals, and the evolution of life, in general. At the Experimental Podcast, Stephanie Vogt talks about the paleophysiologists who are reconstructing the proteins of extinct animals
using fragments of DNA found in long-dead remains. Those proteins, simple as they may seem, hold some amazing stories. For instance, reconstructed haemoglobin from wooly mammoths could someday help doctors get oxygen to the brains of high-risk human surgery patients. Read the rest
There is definitely a seasonality to human births, writes Beth Skwarecki at Double X Science. The complicated bit is that human baby season isn't necessarily the same (or as strongly expressed) from place to place and culture to culture. In the United States, significantly more babies are born in July, August, and September. Meanwhile, in Europe, babies seem to make their way into the world in spring. So there's clearly a cultural component to this — but culture doesn't explain it, entirely. Skwarecki's piece explores a messy place where culture, genetics, and circadian rhythms intersect
. Read the rest
By studying the way it has mutated and changed over time, scientists can trace human mitochondrial DNA — the DNA that is passed from mother to daughter — back to a single woman. Basically, everybody alive is descended from her. But that's not the same thing as saying that Mitochondrial Eve was once the only woman alive. In a very nice piece — with helpful illustrations — the Christian (but evolution-accepting) scientists at BioLogos explain what Mitochondrial Eve really means and why she can't be used as an argument for creationism
. Whether or not you've ever found yourself arguing this point with a family member or friend, the piece is really useful for deepening your understanding of a pop-science concept that's often thrown around without a clear explanation behind it. Read the rest
In 2010, a group of scientists claimed to have found bacteria that could build its DNA using arsenic, instead of the phosphorous used by the rest of Earth's life forms. Within days, the research behind "arsenic life" was under serious scrutiny and we now know that it was totally wrong. But the work was peer-reviewed. It was sponsored by NASA. How do so many experts make such a big mistake?
Dan Vergano at USA Today has an excellent article looking at just that — and it includes the peer review comments that helped the arsenic life paper get published. Though normally secret, Vergano got a hold of them through a Freedom of Information Act request. Read the rest
Last week, I posted a link to a story on the Atlantic
, all about the history of research into supertasters — humans with the ability to taste a bitter compound called phenylthiocarbamide. It's a big part of why some people can't stand the taste of broccoli, and others love it. But that one piece isn't the full story. According to taste geneticist Stephen Wooding, it wasn't even totally accurate. Instead, he suggested three articles that anybody curious about supertasting should read. First, a history of the science that he wrote for the journal Genetics
. Second, a long read by Cathryn Delude about research that might, someday, make broccoli delicious for everybody
. And a University of Utah site that explains the genetics of taste
. Read the rest
Before you get excited about the bones of Richard III being found under a parking lot
, consider this — the announcement included no mention of how common the DNA sequences that ostensibly identified the body as Richard really are. Those sequences might match Richard's descendants, but if the sequences are also really common, well, that's not saying much. Read the rest
For the record, a Harvard scientist is NOT looking for an "adventurous woman" to give birth to a cloned Neanderthal
. Ladies, you can stop filling out those application forms. Apparently, geneticist George Church and the German magazine Der Spiegel
had a bit of a translation problem. Read the rest
Up north — in Canada and other places where snowy winters are reliable (and reliably heavy) — you find more animals whose fur comes in various shades of white. This is true even for species that are brown or black further south. The difference is obvious. But how does it happen? Carl Zimmer presents two possible paths to paleness — random mutation, and fortuitous cross-species mating
. In related news: Golden retrievers are probably getting it on with Canadian coyotes. Read the rest
Boldly going where nobody's gone before. In a lot of ways, that idea kind of defines our whole species. We travel. We're curious. We poke our noses around the planet to find new places to live. We're compelled to explore places few people would ever actually want to live. We push ourselves into space.
This behavior isn't totally unique. But it is remarkable. So we have to ask, is there a genetic, evolution-driven, cause behind the restlessness of humanity?
At National Geographic, David Dobbs has an amazing long read digging into that idea. The story is fascinating, stretching from Polynesian sailors to Quebecois settlers. And it's very, very good science writing. Dobbs resists the urge to go for easy "here is the gene that does this" answers. Instead, he helps us see the complex web of genetics and culture that influences and encourages certain behaviors at certain times. It's a great read.
Read the rest
Not all of us ache to ride a rocket or sail the infinite sea. Yet as a species we’re curious enough, and intrigued enough by the prospect, to help pay for the trip and cheer at the voyagers’ return. Yes, we explore to find a better place to live or acquire a larger territory or make a fortune. But we also explore simply to discover what’s there.
“No other mammal moves around like we do,” says Svante Pääbo, a director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, where he uses genetics to study human origins.