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Genetic Linkage

How the Tabby Got Its Stripes

In 1902's Just So Stories, Rudyard Kipling famously explained how the leopard got his spots in what would today be deemed an extremely racist fable. Now Christopher Kaelin, Kelly McGowan, and Gregory Barsh, from the HudsonAlpha Institute for Biotechnology, have discovered how the tabby cat got its stripes: from a signal in the fetus. Their findings appear in Nature Communications.

 

"The genes that control simple color variation, like albinism or melanism, are the same in all mammals for the most part. However, the biology underlying mammalian color pattern has long been a mystery, one in which we have now gained new insight using domestic cats," said Barsh, who is editor-in-chief of PLoS Genetics.

 

To trace the origins of the common striped coat pattern, the team analyzed gene expression in single skin cells from fetuses collected from feral cats in trap-neuter-release programs being spayed – half of such females are pregnant. The work revealed a novel mechanism behind the origin of stripes, like Jackie's in the photograph.

Alan Turing's Idea

 

To continue reading, go to my DNA Science blog at Public Library of Science.

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New COVID Vaccines and More: A Perusal of ClinicalTrials.gov

The pandemic has upended many practices, among them peer review of technical medical and scientific articles.

 

Lax Peer Review + Social Media = Misunderstanding Science

 

Pre-COVID, the preprint sites bioRxiv.org ("bio-archive," founded in 2013) and medRxiv ("med-archive," founded in 2019) were mainly the province of science and medical journalists, and of course researchers. Preprints are technical papers that haven't yet been peer-reviewed, a process that can take months. Preliminary screens remove outrageous claims and check for plagiarism.

 

Until a few months into the pandemic, the warning on both sites not to report on these papers was hard to navigate to, but seasoned journalists knew to respect the conditions. With general assignment reporters suddenly covering a health care crisis that increasingly required knowledge of virology, immunology, and biotech, medRxiv and bioRxiv became great sources of news.

 

The disclaimer was moved to the opening page: "Preprints are preliminary reports of work that have not been certified by peer review. They should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information."

 

The warning hasn't helped.

 

Skipping peer review leads to confusion and the spread of misinformation, especially through the echo chamber of social media. "COVID Vaccine Preprint Study Prompts Twitter Outrage," for example, details the hoopla over a medRxiv preprint that, according to experts on the statistics used, grossly overestimates the risk of heart inflammation in male teens after taking the Pfizer-BioNTech vaccine. The yelling continues.

 

To continue reading, go to my DNA Science blog at Public Library of Science.

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How snake venom and a smoking cessation drug inspired a nasal spray that blocks COVID

A simple nasal spray that stops SARS-CoV-2 in its tracks? 

 

That could block the coronavirus in the nose, before it can travel down to the lungs or be coughed onto another person, perhaps becoming a powerful partner to vaccines and therapeutics, and easy to administer, store, and ship.

 

It "could allow us to reduce transmission and be able to have a quick response to outbreaks in certain areas of the world," said Jeffrey Nau, CEO of Oyster Point Pharma, based in Princeton NJ. The company recently announced repurposing of the smoking-cessation pill Chantix™ (varenacline), as well as a second molecule in the same class, simpinicline, each as nasal sprays against COVID. The FDA approved Chantix, a Pfizer product, in 2006. Today nearly 400 clinical trials are exploring other uses.

 

To continue reading, go to Genetic Literacy Project, where this post first appeared.

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Viewpoint: ‘The fetus is 1/25th of an inch’ — Texas abortion ban bungles the science on when human life begins

Now that early abortion is essentially banned and criminalized in Texas, with other states soon to debate similar legislation, it's important to reflect on one of the key issues raised by this new law: When does human life begin? Here is a background primer on human prenatal development. 

 

Understanding the biology is more important than ever, because the new Texas law is even more draconian than it appears to be at first blush, if that's even possible. It bans abortion at 6 weeks, but this cutoff is actually 4 weeks after conception when the fetus is 1/25th of an inch. Counting gestation from the last menstrual period is archaic, perhaps a holdover from the days when most obstetricians were male. And as anyone who has ever suspected she is pregnant knows, that reasoning is absurdly wrong. The "morning-after pill" is not a "two-weeks-later" pill. Nonetheless and unfortunately, much of the media have spread the meaningless 6-week factoid.

 

To conntinue reading go to Genetic Literacy Project, where this post first appeared.

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New Target for Treating Huntington’s Disease: Controlling Runaway DNA Repair

When results of a clinical trial of a treatment for a rare disease are disappointing, feelings of despair among hopeful affected families resurface – especially if the only options are repurposed drugs. That's the case for Huntington's disease, an inherited neurological condition that affects about 30,000 people in the US, 16 percent of them children.

 

The HD community is reeling from two such setbacks. But a new approach to halting the runaway expansion of the HD gene (called HTT) that lies behind the illness may reignite hope. The strategy focuses not on the HTT gene itself, but on another with which it interacts – a gene that takes part in repairing damaged DNA. Results appear in Cell Reports.

 

An "Expanding Repeat" Disease

 

"Horse-and-buggy doctor" George Sumner Huntington first described HD in 1872.

 

To continue reading, go to my DNA Science blog, where this post first appeared.

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Returning to Live Music and How a Tiny Mutation Sent Delta All Over the World

Ann Wilson, of Heart fame.

A few nights ago I went to my first live music show since pre-pandemic times: Ann Wilson, the vocalist from Heart. She and her new band were at The Egg, a small ovoid-shaped venue in Albany, New York. We were in the third row, very close to the stage. All of us wore masks, and should a smidge of nostril emerge, an admonishing usher materialized instantly.

 

"It's great to see all of your smiling eyes!" joked Ann as she looked out at the limited-capacity audience. The performers were unmasked, Ann belting out the tunes, the guitarist next to her writhing in the throes of guitar-face, a malady in which a man playing a guitar assumes a simian visage, like Caesar in Rise of the Planet of the Apes caught deep in thought. Who knew that guitar-face would one day deter spread of a virus?

 

The show was amazing, full of rock classics, Heart tunes, and songs Ann wrote during lockdown. COVID restrictions just couldn't reign in long-ingrained concert behavior. And so we all belted out Dream On and Barracuda along with Ann and her band the Amazing Dawgs, our masks undulating to the beat, as I hoped fervently that none of the oldish audience would keel over from asphyxiation.

 

"An Experimental Pop Concert" Simulates Viral Spread

 

This morning I was happy to see a new paper, "The risk of indoor sports and culture events for the transmission of COVID-19," published in Nature Communications. Stefan Moritz and colleagues in Germany staged "an experimental pop concert" in August 2020 and found that good ventilation and "suitable hygiene measures" could limit virus-carrying aerosols and droplets.

 

To continue reading, go to my DNA Science blog, where this post first appeared.

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The Tomorrow War on Amazon Prime Echoes COVID: Science from the Past Saves Humanity’s Future

Scary monsters, time travel, and a female protagonist plucked from The Handmaid's Tale cast: what could be better?

 

A Derivative Plot with Interesting Embellishments

 

In Amazon Prime's new "military science fiction action film" The Tomorrow War, released July 2, young time travelers from 2051 arrive in the middle of a World Cup match near the end of 2022 with a message: humanity is on the brink of extinction from being food for the "Whitespikes." The visitors need new troops to jump ahead to the future. At first I thought the characters were saying "white stripes" and expected the appropriate soundtrack, but the spikes are part of the enemy's phenotype.

 

The Whitespikes appear suddenly, ducking radar and satellites, in November 2048, in northern Russia. They gobble through humanity quickly, leaving a mere half million people. So dire is the future need that military folks and civilians are selected from the populous past for week-long deployments, with no time for training. Only a third survive.

 

The recruits painfully get arm implants that receive signals from a hovering wormhole-based "jumplink" to suck them up into the future. The group ascension reminded me of the people reaching age 30 in Logan's Run floating joyously upward as they attain "Carousel," aka death. The jumplink is far more massive and sophisticated than the clunky bike-like vehicle that hurtled time travelers centuries forward in H. G. Wells' The Time Machine. The sucked-up ones in 2022 are then unceremoniously dumped into a future crawling with fire and destruction and hordes of leaping, slathering, hungry "aliens."

 

To continue reading, go to my DNA Science blog, where this post first appeared.

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Scary Variants and Vaccine Hesitancy Set Up a Perfect Storm – for the Virus

As people in the US grapple with a return to masking to stay ahead of the delta and lambda variants and their coming spawn, researchers are increasingly connecting current epidemiology to modeling predictions. The news isn't good, but we can stop what now seems inevitable – with widespread vaccination.

 

The Cape Cod Cluster

 

On Tuesday, July 27, CDC director Rochelle Walensky updated the media on new guidance recommending that everyone, including the fully vaccinated, wear masks in indoor public settings in areas of substantial and high transmission.

 

"The delta variant is showing every day its willingness to outsmart us and be an opportunist in areas where we've not shown a fortified defense against it. In recent days new data on outbreaks show the delta variant behaves differently than past strains. In rare occurrences, some vaccinated people are infectious after vaccination and may be contagious. This new science is worrisome and unfortunately warrants an update to the recommendations," Walensky explained. (I forgive her anthropomorphizing because she uses "data" as a plural.)

 

News media quickly zeroed in on Cape Cod as the site of the outbreak that prompted the change, and by Friday July 30, CDC's weekly publication the MMWR provided the details:

 

To continue reading, go to DNA Science, where this post first appeared. 

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Cats’ Genomes Make Them Good Models for Human Disease

Over the years, I've shared my home with 17 felines. Several have perched on my printer while I cranked out many articles and books on genetics.

 

Little did I know that the genome of Felis catus is subtly similar to my own. Now, the aptly named Leslie Lyons, an associate professor at the University of Missouri Department of Veterinary Medicine & Surgery, has published an article in Trends in Genetics, "Cats – telomere to telomere and nose to tail, that makes the case for cats as models of human disease. (Telomeres are chromosome tips.)

 

"Approximately 33% of households in the USA own a cat, and as pets, cats have evolved from vermin control to beloved family members," Lyons writes. In the US, 42.7 million households include at least one feline.

 

Cats Are More Genetically Diverse Than Us

 

I've always been amazed at genome analyses that indicate species that are more genetically diverse than we are, when one chimp looks more or less like another to us. Cats are more genetically diverse than us, too.

 

The first genome sequence of a domestic cat was published in 2007. That individual was a 4-year-old Abyssinian named Cinnamon, whose lineage traces back several generations to Sweden.

 

To continue reading, go to DNA Science, where this post first appeared.

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Katla on Netflix: Volcanoes, Glaciers, and Meteorites, Oh My!

I usually write about a sci fi book or film midsummer. That's more necessary this summer than ever, when science reality – half a population refusing vaccination inviting natural selection to favor ever-deadlier (and perhaps vaccine-resistant) viral variants – is far more alarming than anything anyone could make up. So I was easily sucked into Katla, a terrific 8-part series on Netflix.

 

As the first episode opens, it's a year after a massive eruption of Katla, a volcano that looms over the small seaside village of Vík in southern Iceland, about 115 miles from Reykjavik. Until the blast, a glacier capped Katla. In real life, the human population of the village boomed to 683 in 2018, thanks to increased tourism, but I suspect it may have ebbed again due to the pandemic.

 

In the show, strange things start to happen among the holdouts who don't leave the ashy landscape for Reykjavik. Beings begin to stagger out of the hell in the distance, covered in a black goo: animals like birds, cows, and goats, but then people too. And that's when things begin to get weird, because the people who come forth from the volcano were dead.

 

To continue reading, go to DNA Science, where this post first appeared.

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