The U.S. Department of Justice (DOJ) this week released new rules that limit when police can access family tree DNA databases to identify crime suspects. This new genealogy policy is the first ever at the federal level to address how online genetic databases sold as services to the public can be used in law enforcement. Read the rest
An investigation by the health ministry in Guangdong, China determined that scientist He Jiankui broke national laws when he used the CRISPR gene-editing technique to engineer human embryos with resistance to HIV and then implanted the embryos into women who then birthed the babies. Based on the probe, the Southern University of Science and Technology has fired He from his position as a researcher and teacher there. According to an article in the Chinese state media outlet Xinhua, police may also explore charges against He and his colleagues. From Nature:
The Xinhua article confirms many details of the case for the first time: starting in June 2016, it says, He put together a team that, from March 2017, recruited eight couples consisting of an HIV-positive father and an HIV-negative mother. He’s team edited the genes of embryos from at least two couples. (The Xinhua article does not specify what type of gene editing was done, although He claims that the embryos were edited to remove a gene that enables HIV to enter cells.) In addition to the woman who already gave birth, one other woman involved in the experiment is currently pregnant with a gene-edited embryo. Five other couples are not pregnant, the article reports, and one couple dropped out of the experiment.
The article says that He’s gene-editing activities were “clearly prohibited by the state”, but it doesn’t mention which specific laws or regulations the researcher broke.
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Today I learned that using cannabis can lower a fella's sperm count: those looking to partake in parenthood should take note. But that's not the only thing that cannabis can do to your swimmers. According to scientists from Duke University, using marijuana can cause genetic changes to sperm cells--something that could have far-reaching consequences for any baby a dude might father.
From The Verge:
For a study published today in the journal Epigenetics, scientists at Duke University compared the sperm of two groups of rats: those who had been given tetrahydrocannabinol (THC), the psychoactive ingredient in cannabis, and those who had not. Then they compared the sperm of 24 human men who smoked marijuana weekly versus a control group who used marijuana no more than 10 times in their life and not at all in the past half-year. In both cases — rats and humans — marijuana changed how genes work in sperm cells.
In both rats and humans, the cannabis affected many different genes involved in two different pathways. (Think of pathways as another set of instructions, this time for regulating various bodily functions.) One is important for organs to reach full size, and one plays a role in cancer and suppressing tumors.
Before anyone loses their shit, this doesn't mean that any kid you conceive while THC is coursing through your body will be more likely to get cancer. A lot more research needs to be conducted before any firm conclusions can be drawn. As The Verge points out, there were no laboratory controls on how much THC was consumed by the test subjects. Read the rest
A research team from Imperial College London have published promising results of an experiment in which Anopheles gambiae mosquitoes -- responsible for the spread of malaria -- were genetically modified with a stable, gene-drive-based CRISPR modification that caused them to go extinct in the lab.
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When a deaf Czech girl had her genes tested, researchers were surprised to find two sets of her father's genome spliced, leaving almost none of her mother's genome. Only about 25 girls and zero boys have ever been found with this trait. Read the rest
Yeast has brought a lot of joy into the world, but its evolutionary origins were unclear until scientists did a worldwide genomic survey of the humble organism. Based on the genetic diversity of strains found in China, they concluded that its origin is almost certainly in that part of the world. Read the rest
George Church's Harvard lab is one of the most celebrated fonts of innovation in the world of life sciences. George's earliest work on the Human Genome Project arguably pre-dated the actual start of that project. Subsequently, he's been involved in the creation of almost a hundred companies - 22 of which he co-founded.
Much of George's most recent and celebrated work has been with a transformationally powerful gene-editing technique called CRISPR, which he co-invented. George and I discuss CRISPR and its jarring ramifications throughout this week's edition of the After on Podcast. You can listen to our interview by searching "After On" in your favorite podcast app, or by clicking right here:
Our conversation begins with a higher-level survey of the field -- one which cleanly and clearly defines CRISPR by placing it into a broader, and also a quite fascinating framework. We cover four topics, which I'll now define up-front for you, so as to make the interview more accessible.
We begin by discussing genetic sequencing. "Sequencing" is a fancy (and rather cool way) of saying, "reading." Your genome is about three billion characters long. It's written in a limited alphabet, of just four letters: A, G, C, and T. And if someone sequences your genome, it simply means they've read it. They haven't modified it in any way. They haven't have cloned you. They've just gotten a readout (kind of like determining your blood type -- only a few billions times more complicated).
George and I next discuss gene editing. Read the rest
This is Ata, a bizarre, tiny mummified skeleton found in a deserted mining town in Chile's Atacama Desert in 2003.
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Scientists analyzed almost a quarter million DNA samples in the UK Biobank and found 538 new genes that appear to have a role in intellectual capabilities. Read the rest
A Scottish team of animal biotechnologists announced this week they successfully introduced human stem cells into sheep embryos. Perhaps one day we will all have our very own baaing organ donors.
The team are currently allowed to let the chimeric embryos develop for 28 days, 21 of which are in the sheep. While that might be sufficient to see the development of the missing organ when human cells are eventually combined with the genetically modified embryo, Dr Hiro Nakauchi of Stanford University, who is part of the team, said a longer experiment, perhaps up to 70 days, would be more convincing, although that would require additional permission from institutional review boards.
But, Ross said, for the approach to work it is thought that about 1% of the embryo’s cells would have to be human, meaning further work is needed to increase the proportion of human cells in the chimera.
Nakauchi also played down concerns: “The contribution of human cells so far is very small. It’s nothing like a pig with a human face or human brain,” he said
Who .... who said anything about... pigs with human faces and brains? Read the rest
Imagine that a folded note before you reveals -- definitively -- whether an excruciating, protracted neurological death lies a decade into your future. Should you look?
Do so, and you could be rid of the grim uncertainty. Or, you could be fated to live and die with an awful truth. One which will haunt you, but also let you shape your remaining years with a foreknowledge most of us lack.
This is a terrible quandary no one should face. But one person in 10,000 carries a genetic vulnerability to a gruesome affliction called Huntington’s Disease. You almost certainly do not. But for those with a family history of Huntington’s, the odds can be as high as 50/50. And in certain genetic configurations, the disease has 100% “penetrance” - meaning that all who carry the mutation are doomed. This makes the results of a Huntington’s test as close to an iron-clad prediction as genetics ever gets.
Before the test was created, a remarkably high percentage of people with family histories said they’d take it if given the chance. But once the test was available, roughly 90% of those people changed their minds. This makes it nigh impossible to know what we ourselves would do if faced with that choice.
But all of us will face a version of that choice very soon - albeit a far less stark, and radically more ambiguous version. And roughly 0.000% of us are in a position to make that choice in an adequately-informed and emotionally-prepared manner. Read the rest
Matthew Combs, a Fordham University Louis Calder Center Biological Field Station grad student worked with colleagues from Fordham and the Providence College Department of Biology to sequence the genomes of brown rats in Manhattan, and made a surprising discovery: the geography of rats has a genetic correlation, so a geneticist can tell where a rat was born and raised by analyzing its DNA.
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National Geographic interviewed geneticist Adam Rutherford, author of A Brief History of Everyone Who Ever Lived: The Stories in Our Genes. "In many ways, genetics makes a mockery of race," he notes. Read the rest
The field of epigenetics continues to make interesting discoveries about environmental effects on genetic material. A team led by Thomas McDade found that children's experiences affected their DNA, which in turn affected suscepitability to certain diseases. Via Smithsonian:
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Their investigation followed more than 500 children in the Philippines and found that certain childhood situations can create modifications in genes associated with inflammation, which affects how prone we are to suffer from certain illnesses. Specifically, these factors included socioeconomic status, the prolonged absence of a parent, the duration of breastfeeding, birth during the dry season, and exposure to microbes in infancy.
This cohort comprised over 3,000 pregnant women recruited in the Philippines in 1983. These women came from all different walks of life: They differed in access to clean water or a roof over their heads, whether they lived in an urban or a rural area, and whether they came into frequent contact with animals. From the data, they looked at over 500 of those women in order to figure out if their child’s environment growing up led to epigenetic modifications to their DNA—and later to a change in inflammatory proteins in their blood in adulthood.
Once their children were born, the investigators kept track of them and of the environments they were exposed to throughout their lives. Once they turned 21, the investigators took a blood sample that they used to measure the DNA methylation throughout their genome, as well as inflammation-related proteins that have been previously associated with cardiovascular diseases and other aging-related diseases.
The psilocybin in magic mushrooms is a potent psychedelic for animals. But what good is the psilocybin for the shrooms? New genetic research from Ohio State University suggests that the psilocybin might act as an insect repellant, protecting the mushrooms. From New Scientist:
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The gene cluster (linked to psilocybin production) is found in several distantly related groups, suggesting that the fungi swapped genes in a process called horizontal gene transfer. This is uncommon in mushrooms: it is the first time genes for a compound that is not necessary for the fungi’s survival – called a secondary metabolite – have been found moving between mushroom lineages.
Since these genes have survived in multiple species, Slot thinks psilocybin must be useful to the fungi. “Strong selection could be the reason this gene cluster was able to overcome the barriers to horizontal gene transfer,” (researcher Jason Slot) says.
Hallucinogenic mushrooms often inhabit areas rich in fungi-eating insects, so Slot suggests psilocybin might protect the fungi, or repel insects from a shared food source, by somehow influencing their behaviour.
British geneticist Adam Rutherford is one of the country's great science communicators, an alumnus of Nature
whose work we've celebrated here
for many years
; with his second book, A Brief History of Everyone Who Ever Lived
, Rutherford reveals how the century's astounding advances in genetic science reveal just how little we understand about our genes -- and how our ideas about race and heredity are antiquated superstitions that reflect our biases more than our DNA. (See the bottom of this post for an important update about the upcoming US edition!