Ricki Lewis

DNA is the calling card of life. 

In and on our bodies, traces of DNA sequences other than our own announce the presence of many microbes, our microbiome.

DNA in Natural and Artificial Ecosystems

In the environment, snippets of environmental, or "e" DNA, are also abundant, yet more dynamic, constantly changing, compared to the more staid microbial communities inhabiting our skin folds, intestines, armpits, and elsewhere. Airborne eDNA sequences in natural ecosystems are particularly in flux, as species come and go. 

Human-made (artificial) ecosystems also have transient microbial residents that leave in their wake genetic material. One early study probed the short sequences of DNA mired in sticky goo scraped from banisters and stairways of a New York City subway stop, where millions of commuters regularly deposit the microoganisms on their skin.

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

About 100 million adults and 100 million children worldwide have the red, flaky, itchy skin of the most common form of eczema, atopic dermatitis, according to the NIH. The condition stems from a misdirected immune response to a substance – an allergen – that does not actually present a threat. Although the exact causes of eczema aren't well understood, a new study points to an unexpected protective factor: owning a dog.

Allergies like eczema arise from complex interactions of genetic and environmental factors. The new report, in the journal Allergy, is from an international team. The investigators pooled and analyzed the results of many studies to identify possible contributing factors to developing eczema.

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

I love when fiction unfurls a compelling tale whose protagonist has an ultrarare genetic disease.

My most recent favorite is The Sirens. Author Emilia Hart weaves a powerful tale of genetic memory manifest in two pairs of sisters, one aboard a doomed ship transporting women convicts from England to New South Wales circa 1780, the other contemporary.

But before The Sirens came Middlesex and The Covenant of Water. Each elaborates a complex plot around an unusual condition caused by mutation in a single gene. And all three present solid science – a story is a great way to learn genetics.

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

Nine-month-old KJ Muldoon made global headlines following a report in The New England Journal of Medicine, from Kiran Musunuru and Becca Ahrens-Nicklas and their team at Children's Hospital of Philadelphia and Penn Medicine. They used a highly precise form of CRISPR gene editing to correct a mutation – swapping out one DNA base for another – that lay behind the boy's inability to break down proteins in food.

Left unchecked, ammonia would have accumulated to toxic levels in KJ's bloodstream, which would have rapidly lead to organ failure and, ultimately, brain swelling and coma. He was hospitalized until he received the new treatment, kept on a very low protein diet.

The boy inherited one mutation from each parent, and so he couldn't produce a crucial enzyme, carbamoyl phosphate synthetase 1 (CPS-1 deficiency). The condition affects only 1 in 800,000 to 1,300,000 newborns, and it is quickly fatal in half of them.

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

It's odd for me, as a long-time author of college biology textbooks, to witness governments rule on the nature of biological sex, perpetuating an oversimplified, binary definition.

A recent edition of The Week, in "The World at a Glance," relates that Britain's Supreme Court has defined a biological female: "While trans people are protected from discrimination under the 2010 Equality Act, the categories of 'man' and 'woman' in that act must refer to 'biological sex' because any other definition would be 'incoherent and impracticable.'"

Ditto Hungary. A constitutional amendment officially recognizes only male and female, banning LGBTQ groups from holding public events. Prime Minister Viktor Organ claimed inspiration in his biological dictate by the US's recent take on sex determination and gender identity.

"DEFENDING WOMEN"
The US president proclaimed the basis of binary biological sex in the January 20 executive order DEFENDING WOMEN FROM GENDER IDEOLOGY EXTREMISM AND RESTORING BIOLOGICAL TRUTH TO THE FEDERAL GOVERNMENT – CAPS his. The statement conjures Captain Picard, in Star Trek Next Generation, uttering "make it so."

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

Next month, families affected by the rare genetic disease metachromatic leukodystrophy (MLD) will meet in Washington. They will be protesting the April 4 dissolution of the committee of experts that advises Health and Human Services (HHS) leadership on which conditions to include on the Recommended Uniform Screening Panel, aka the RUSP.

The List
RUSP is a state-by-state roster of up to 61 "actionable" metabolic conditions. If they are detected shortly after birth with a few drops of blood from the heel, treatment is possible. But it must begin ASAP.

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

The images of "de-extincted" fuzzy white dog-wolf pups festooning the media this week accompany reports that are so hyped that the technical feat is hidden in the hoopla.

Claimed the company, Colossal Biosciences:

"On October 1, 2024, for the first time in human history, Colossal successfully restored a once-eradicated species through the science of de-extinction. After a 10,000+ year absence, our team is proud to return the dire wolf to its rightful place in the ecosystem. Colossal's innovations in science, technology and conservation made it possible to accomplish something that's never been done before: the revival of a species from its longstanding population of zero."

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

Hitler's "final solution" attempted to strip the German population of Jewish people and others deemed not white. At the same time, the Lebensborn program sought to purify the Aryan gene pool and counter a plunging birthrate through "homes" where "hereditarily healthy" Aryan women conceived, carried, and bore the "racially valuable" children of SS men.

Adriana Allegri's debut novel The Sunflower House (St. Martin's Press, 2024) captures the slow-building horror that unfolded at the Hochland Home in Steinhöring, the first facility in the program.

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

When I heard that 23andMe had filed for bankruptcy, I wasn't alarmed, at first. I'd taken a test from the company, years after I did one for AncestryDNA at a genetics meeting – I hadn't even remembered taking that first test.

I knew 23andMe would someday be in trouble, despite the yearly blitz of ads at holiday time, because of the ephemeral value of their DNA tests – there wasn't a viable way to keep customers on the hook.

Privacy hadn't bothered me. If someone wanted to know my SNP (genetic marker) profile, or the fact that I have more Neanderthal DNA than most people, so be it. The company wasn't sequencing genomes, just identifying a few hundred thousand places in the genome where people vary in the DNA base – A, C, T, or G – a little like a map of state capitols rather than of all streets.

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

Measles virus has long occupied a top spot on a list of most dangerous pathogens, for in addition to spreading easily, it can temporarily cancel immunity against other infectious diseases. A powerful vaccine has vanquished measles since 1963, offering close-to-lifetime immunity. But the disease is returning, thanks to vaccine hesitancy and apparent lack of knowledge of basic biology.

I was too young to remember having measles. But my mother told me I was very sick for a month, and was a day away from being hospitalized for encephalitis when I finally began to improve.

Circa 1960, everyone got measles. In a room full of vulnerable individuals, some 90 percent will quickly become infected, as the virus wafts in droplets dispersed in the air, hanging around for up to two hours. Having the telltale spots, however, conferred lifelong immunity.

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