Ricki Lewis

A 52-year-old woman is at her annual physical exam. The physician assistant mentions he'll need two extra vials of blood for new cancer screening tests, one just FDA-approved, the other available as part of a clinical trial.

 

"But I already get mammograms and colonoscopies based on family history, and my husband gets his PSA screen for prostate cancer every year. So far, so good. Why do I need these new tests?" the patient asks.

 

"They can catch cancers much earlier, from DNA and proteins in your blood plasma, the liquid part. Including cancers much rarer than breast, colon, and prostate."

 

"Sure," says the patient, rolling up a sleeve. She'd be one of the first to have "multi-cancer early detection" – MCED – blood tests that zero in on clues that cancer cells shed into the bloodstream. A treatment begun early is more likely to work. An MCED blood test could be a gamechanger for people who haven't had cancer.

The end-of-year FDA approval of the first CRISPR-based therapy, for sickle cell disease, came a mere dozen years after Jennifer Doudna and Emmanuelle Charpentier introduced the technology. They shared the Nobel Prize in Chemistry in 2020.

 

CRISPR is one of the better abbreviations in genetics. It's certainly more memorable than RFLPs, GWAS, and even SNPs, so euphonious that few reports – technical or otherwise – actually use the term "clustered regularly interspaced short palindromic repeats." CRISPRs are short DNA sequences, peppered with repeats, that latch onto DNA-cutting enzymes, commandeering and directing them to snip certain parts of a chromosome.

 

The genomes of certain bacteria naturally harbor CRISPR sequences. The microbes deploy them to dismantle the genetic material of infecting viruses, a little like an immune response.

 

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

A few weeks ago, I noticed a surprising metric when posting my weekly DNA Science blog – at year's end, I'd hit #500!

 

That got me thinking. Looking back, which blog post was the most important? The answer came to me quickly – but it's not what I would have expected when I began more than a decade ago.

 

The Birth of DNA Science

 

When St. Martin's Press was about to publish my book about gene therapy in 2012, my agent urged me to start blogging. I needed to widen my audience beyond college students forced to buy my textbooks and readers of the articles I'd been cranking out since the 1980s.

 

The book that kickstarted DNA Science was The Forever Fix: Gene Therapy and the Boy Who Saved It. It's a history of gene therapy told through the voices of the patients, families, researchers, and clinicians behind the first FDA approvals, which didn't come until 2017.

 

I launched a website and blog, "Genetic Linkage," through the Author's Guild. Soon, an editor at Public Library of Science asked me to post Genetic Linkage at PLoS. We renamed it DNA Science.

 

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

"Enchant your loved ones with nature's lost scents, revived through biotechnology and perfume artistry."

 

When that popped up on Facebook, I was intrigued. So I clicked.

 

"Meet Invisible Woods: a clean, refreshing scent revived from extinct flower DNA," beneath an image of "origin flower" Wendlandia angustifolia.

 

A quick search revealed that this plant had been presumed extinct, until one popped up in a 1998 survey of its natural habitat in Tamil Nadu, India. Invisible Woods is not really "revived," but "reimagined," using clues from ancient flowers and the tools of biotechnology.

 

Future Society offers six fragrances inspired by past plants, for $98 per 50 milliliters (a little under 2 ounces) or a $35 sampler ideal for a stocking stuffer. Boston-based Ginkgo Bioworks provides the expertise in genetics.

 

I don't use scented products other than Pine-Sol, so this was all new to me. DermNet defines "fragrance" as a combination of organic compounds that produces a distinct smell, whereas a perfume is a liquid mixture that emits a pleasant odor, and oilier than a fragrance. I don't exactly get the distinction, but apparently perfume is the oilier of the two and perfume, cologne, and aftershave are all fragrances.

 

Before I dig into the science, I'll relate taking a quiz on the Future Society website that would help me choose a product. I clicked on the "friend" option, my bestie, Wendy. 

 

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

Anyone who lives with more than one member of Felis catus knows that our beloved felines love to smell each other's anal regions. Now a research team from the Department of Evolution and Ecology and Genome Center University of California, Davis, explains why, with their cataloging of the microbiomes of domestic cat anal glands. The bacterial members of the microbiome produce and release organic compounds that affect the behavior of another cat. The findings are published in Scientific Reports.

 

A microbiome is the collection of microbes that live in or on an organism. The microbiome accounts for 90 percent of a person's cells, packed in because bacterial cells are so much smaller than ours. These microscopic residents live under our arms, between our toes and butt cheeks, in our guts and noses and spleens and eyebrows and, well, everywhere.

 

The new cat study compared the DNA sequences of a gene commonly used in evolutionary investigations, to identify bacterial species residing in domestic feline anal glands. The investigators also identified the "volatile organic compounds" (VOCs) that the anal glands emit, thanks to those microbes. The study evaluated anal gland emissions of several other mammals, including dogs, hyenas, foxes, pandas, and of course humans.

 

An Explanation from Microbiology

 

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

After a long career as a science writer, textbook author, and genetic counselor, I've become an accidental authority on squashes.

 

I began volunteering at the largest food pantry in my small city in June 2020, where my husband Larry had been in charge of the plant and fungal kingdoms for years. It was the height of the pandemic. So gloved and masked, we shoved fruits and veggies into plastic bags, filled shopping carts with the bags, and wheeled them over to a window at which another masked, gloved volunteer quickly pushed the bags to the clients waiting outside.

 

Like most activities back then without human contact, it wasn't much fun.

 

Nowadays, Larry and I help the clients choose fruits and veggies, and I share cooking and storage tips as well as recipes. I love the challenge of figuring out how to prepare something unfamiliar – plantains, Jerusalem artichokes, broccoli rabe.  

 

My favorite client is a 95-year-old Ukrainian woman. I know which days she'll show up with her helper, so I assemble bags of bountiful beets so she can make borsht for her congregation. Schenectady has a large Guyanese community, and the ladies with whom I share tips and recipes call me "mommy." I tell our Black clients how to make stuffed cabbage; they share how to cook collards.

 

But I'm still a biologist at heart. Here at DNA Science a few years ago, I shared The Peaceable Genomes of Pumpkins.

 

For this year's Thanksgiving post, I came upon an article, Genomic Prediction and Selection for Fruit Traits in Winter Squash, published in G3: Genes, Genomes, and Genetics, from Michael R Mazourek of Cornell University and colleagues, from 2020.

 

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

 

 

The email from my former neighbor Shaun Kuczek was unexpected.

 

"Hi Ricki! My Dad passed in July, and we're cleaning out his house. He was a biology teacher for 35 years and I have 40 or so old biology textbooks. I remember that you write biology textbooks, and maybe you have an idea of a way to pass them along? They're all old, 1950s, 1960s. If you think of anything, please let me know."

 

Bernie Kuczek had been 91. In addition to teaching high school biology and chemistry and coaching baseball, Bernie's claim to fame was being drafted by the Brooklyn Dodgers and sitting alongside Jackie Robinson in the dugout. Alas, a broken leg ended his baseball career. Bernie served in the Korean War and worked summers as a fisheries biologist.

 

Treasure from 1952, Just Before Watson and Crick's Paper

Last week DNA Science covered a setback in a clinical trial of a gene therapy for Duchenne muscular dystrophy (DMD). Also recently, FDA's Cellular, Tissue, and Gene Therapies Advisory Committe turned down a stem cell treatment for amyotrophic lateral sclerosis, aka ALS, Lou Gehrig's disease, or motor neuron disease.

 

The two conditions and the therapeutic approaches differ, but their clinical trials illustrate the importance of selecting patients whose characteristics suggest that they are the most likely to respond.

DMD affects 1 in 3,500 male births, compared to approximately 1 in 400 people who develop ALS during their lifetime.

 

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

In the final chapter of my 2012 book The Forever Fix: Gene Therapy and the Boy Who Saved It, I predicted that the technology would soon expand well beyond the rare disease world.

 

I was overoptimistic. Gene therapy clearly hasn't had a major impact on health care, offering extremely expensive treatments for a few individuals with rare diseases. We're still learning possible outcomes of sending millions of altered viruses into a human body. Can they deliver healing genes without triggering an overactive immune response?

 

A report in the September 28, 2023 The New England Journal of Medicine describes a young man with Duchenne Muscular Dystrophy (DMD) who died just days after receiving gene therapy. The details are disturbingly reminiscent of the famous case of Jesse Gelsinger, who died from a ferocious immune response to experimental gene therapy in September 1999.

 

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

When it comes to estimating risk of a disease that is either genetic or has a genetic component, ancestry of an individual plays an important role. That's because increased risk of a particular health condition may be associated with a gene variant (aka mutation) in one population, but not another. Someone from a group not represented in the data on which a clinical test is based could receive an incorrect risk assessment, or even prescribed a drug unlikely to work.

 

A team from the Johns Hopkins Bloomberg School of Public Health and the National Cancer Institute has developed a new algorithm for genetic risk-scoring for major diseases across diverse ancestral populations. Their findings are published in Nature Genetics.

 

Although the algorithm is a start, and takes a logical approach to address health care disparities, it doesn't go far enough. Considering large groups – like Latinos or Africans – doesn't parse humanity sufficiently to hold much predictive power for genetic diseases, or conditions with large genetic components.

 

Tools to Track Disease: Biobanks to AI

 

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