12th edition of my human genetics textbook


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Glenn Nichols, surrounded by his hospice team. The author is in yellow.

Genetic Linkage

Alternate Facts: Why Are We Still Telling Women That Abortion Causes Breast Cancer?

July 20, 2018

Tags: abortion

On June 26th, the Supreme Court ruled in favor of crisis pregnancy centers that were challenging a California law, the Reproductive Fact Act, requiring clinic personnel to inform women of all family planning options — including abortion. The 5-to-4 vote put First Amendment rights of workers whose religion is against abortion above the rights of pregnant women to be told that California provides free or inexpensive family planning information, including abortion.

While critical information about abortion is omitted at many of the crisis pregnancy centers, misinformation is apparently readily dispensed. One popular mantra is that abortion causes breast cancer. It’s a claim likely to scare the daylights out of young, vulnerable women seeking help. But a deep-dive into studies published in the top medical journals shows it is untrue — but findings of those investigations tend not to be shared.

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

Telomere Testing: Science or Snake Oil?

July 16, 2018

Tags: telomeres

It seems lately that any biometric can inspire a test pitched to consumers, using jargony buzzwords and promises of health, wellness, and longevity. Measuring the length of telomeres, the short DNA sequences at the tips of chromosomes that whittle down as we age, is one such pseudoscience-based offering.

“The DNA test to help you stay younger longer,” and “control how well you’re aging based on your telomere length,” blares one website. Send in a swab and receive “your current telomere length reported as the age of your cells in TeloYears, and the option to work with an expert to develop a personalized lifestyle improvement plan based on telomere science.”

Not surprisingly, Telomere Support supplements are available to help achieve the promised stoppage of time. These include the usual suspects of vitamins and anti-oxidants, plus black tea extract and pygeum extract (from the African cherry tree, used to treat an enlarged prostate). Only $59 a month!

Another company offers to tell the consumer “physiological/biological age” via the mean length of the telomeres, with a deal to test four times a year for $299, to track changes.

I’m not buying any of it.

Yes, diseases can result from abnormal telomere maintenance, but that’s got nothing to do with what the companies are pitching. Two new articles in the Mayo Clinic Proceedings report on 17 patients with short telomere syndromes, while a third article, a commentary, tackles the commercialization of the science, "Telomeres in the Clinic, Not on TV".

Continue reading at DNA Science, my blog for Public Library of Science.





Hybrid White Rhino Embryos: Genetic Rescue, Part 2

July 10, 2018

Tags: rhinoceros

Two weeks ago, DNA Science covered the plight of the northern white rhino, suggesting assisted reproductive technologies (ARTs) that might preserve the genomes of the nearly-extinct subspecies. A paper published last week, in Nature Communications, reports creating embryos by injecting northern white rhino sperm nuclei into southern white rhino oocytes (unfertilized eggs).

The hybrid rhino embryos developed to a key early stage, the hollowed-ball blastocyst. If they can survive transfer to surrogate southern rhinos and continue developing, it would demonstrate that at least one route to salvaging the subspecies may be possible. But it might not be enough.

The blastocysts are “the first in vitro produced rhinoceros embryos ever,” said co-author Thomas Hildebrandt, of the German Leibniz Institute for Zoo and Wildlife Research. The northern white rhino population is down to just two infertile females (Najin and her daughter Fatu). The last male, Sudan, died in March. The southern subspecies is some 21,000 animals strong. Yet ironically, the genomes of northern animals, albeit based on a handful of samples, are more diverse.

The hybrid embryos, harboring one southern and one northern genome, are halfway to the goal of re-establishing a founding population of the dwindling subspecies. Mating the hybrids for several generations, serially selecting offspring with the highest percentages of northern DNA, could approach reconstituting the genome of the northern white rhinoceros, given time and luck. This is classical genetics sprung from an assisted reproductive technology.

Continue reading at DNA Science, my blog for Public Library of Science.


The Genetic Power of Jurassic World: Fallen Kingdom

July 4, 2018

Tags: dinosaur, Jurassic Park

The latest installment in the Jurassic Park franchise, coming a quarter century after the first film, is about the “genetic power” of the cloned dinosaurs. Only it really isn’t.

The plot is superficially superficial – reviews seem more focused on Bryce Dallas Howard’s improved footwear from the last go-round, pointing out the thin plotline. But many missed the subtleties and subtext of the science.

I scribbled in the dark theater, as I did when reviewing the ridiculous Rampage a few weeks ago. Fallen Kingdom is much better – at least some thinking went into it.

Save the Dinosaurs!

When last we saw the dinos in 2015, they were running amok on Isla Nublar, 150 miles to the west of Costa Rica. Now a huge volcano has started to sputter. What to do? After all, we brought them back, posits Jeff Goldblum, reprising his mathematician-turned-biologist Ian Malcolm persona in the first scene, deploying multisyllabic words when addressing a befuddled senator. The beasts are facing an “extinction level event.”

Continue reading at DNA Science, my blog for Public Library of Science.

Battling Constipation with Synthetic Biology and DNA Manipulation

June 28, 2018

Tags: constipation, microbiome, synthetic biology

Worldwide about 15 percent of people suffer from constipation. Passing dry, compacted stools can be quite painful, but eating more fruit, drinking more water, and/or taking laxatives – common advice from friends and physicians alike – can lead to frustration rather than relief. And drugs such as linaclotide (Linzess) and plecanatide (Trulance), and even probiotics don’t work for everyone because our gut microbiomes (the bacteria in our stomachs and intestines) differ.

A few novel approaches are on the horizon, according to Clinicaltrials.com, including new laxatives, acupuncture, reflexology, Chinese herbs, and a Brazilian tea brewed from fruits of green anise and fennel and flowers of senna and elder tree. Old remedies are given new names, like "Movicol." It’s just sodium bicarb stabilized with the laxative polyethylene glycol (PEG), which is the infamous elixir taken the night before a colonoscopy. It works.

Other experimental strategies are more invasive. “Interferential therapy” zaps the abdomen with four electrodes, and is performed at home for an hour a day for two to three months. Another is a "vibrating capsule,“ presumably inserted into the anatomical area of concern. In another clinical trial, 100 people are testing “perineal self-acupressure,” massaging the anal area to break up and mobilize the stool. And fecal transplants are being tested too.

But a fecal transplant seems the opposite of precision medicine: receiving trillions of bacteria from someone else, each microbial species exuding its own smorgasbord of biochemicals. Although the approach is both ancient and effective, with such a mixed bag of ingredients, evaluation is largely empiric – it helps or it doesn’t, to treat recurrent Clostridium difficile infection and several other indications in clinical trials.

Biotech harnesses tryptamine
Purna Kashyap, M.B.B.S., associate director of the Mayo Clinic Center for Individualized Medicine and his colleagues sought to harness a specific molecule, tryptamine, to loosen stool and speed its transit from inside to outside. “Our goal with this research is to find treatments that act only in the GI tract without creating problems in other parts of the body,” he said. The work is published in the June issue of Cell Host & Microbe, including a video.

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

Genetic Rescue of the Northern White Rhino

June 27, 2018

Tags: rhinoceros

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People are taking eclectic approaches to saving rhinos from poachers.

Tracking devices on the animals detect an increase in heart rate when danger approaches, like a FitBit wearer encountering a dog that’s sprung it’s invisible fence.

A concoction of rhino keratin (the protein that forms the horn) made in recombinant yeast and rhino DNA (to mark its authenticity) offers a substitute that may keep poachers away.

The Rhino Rescue Project captures rhinos, injects dye into their horns, then releases them, the stain rendering the appendage less desirable to hunters. Dehorning is another approach.

Such efforts may appear to be too late for the brink-of-extinction northern white rhino, but results of a new study published in Genome Research offer hope: genome sequences of nine northern white rhinos reveal a genetic diversity that may provide a way to save them. “Our study demonstrates the emerging role for whole genome sequencing analysis to evaluate the potential for population recovery,” said Cynthia C. Steiner, from the San Diego Zoo Institute for Conservation Research and director of the study. (more…)

New Treatment for Phenylketonuria (PKU) Clears Brain Fog

June 21, 2018

Tags: PKU

In the 1959 novella Flowers for Algernon by Daniel Keyes (and the 1968 film Charly), 32-year-old Charlie Gordon, a janitor at a New York City bakery, undergoes experimental surgery that has boosted the intelligence of a laboratory mouse, Algernon. Soon, Charlie is devouring books, asking questions, and even solving problems at work. But then Algernon dies, and in a short while Charlie returns to his normal state of intellectual dullness. But now he becomes distraught, recognizing his limitations in a way that he didn’t before the surgery.

Dan Peterson is about Charlie’s age, and he, too, has recently experienced a new clarity of thinking thanks to a treatment. In Dan’s case it’s an enzyme substitution therapy called Palynziq (pegvaliase-pqpz), which he injects under his skin daily. FDA approved it on May 24 to treat phenylketonuria (PKU). But unlike Charlie’s brief experience, Dan’s treatment should last. (more…)

Why We Aren't Yet on the Verge of a Preemie Prediction Test

June 21, 2018

Tags: preemie

(Versys Clinics)
Earlier this month, I saw an interesting juxtaposition of newly-published papers making headlines. One was about predicting breast cancer recurrence and the effect on chemo choice, the other on predicting premature birth within two months of the due date.

Apples and oranges, perhaps, but both indications use the same technology: gene expression profiling (measuring messenger RNAs, aka transcripts, which guide synthesis of specific proteins). But the studies are at opposite ends of the research trajectory, with the breast cancer paper representing thousands of patients who’ve taken a test that’s been on the market for years, and the prematurity paper a pilot study of only a few dozen women. (more…)

Gene Therapy for Myotubular Myopathy: Early Signs of Success!

June 11, 2018

Tags: myotubular myopathy, gene therapy

Paul Frase with his son Joshua.
Parents cherish developmental milestones, from a newborn’s grip of an offered finger; to an infant’s holding her head up the first time; to rolling over, creeping, and crawling; then to standing, cruising, and finally walking. Even kicking during a diaper change or yowling requires muscle strength and coordination. But a boy with X-linked myotubular myopathy (MTM) is so weak that even breathing is a huge struggle. If a baby survives the initial hospital stay, care at home becomes a full-time job and is only supportive, delaying the inevitable. That grim picture may be changing. (more…)

Can the Egyptian Fruit Bat’s Unusual Genome Show Us How to Fight Deadly Marburg Virus?

June 11, 2018

Tags: Egyptian fruit bat, Marburg virus, Ebola

The Egyptian fruit bat's immune system enables it to peacefully co-exist with Marburg virus, which can cause a swiftly deadly infection in humans. Although Marburg virus disease affects only a few dozen or hundred people a year, the case:fatality ratio in the scattered outbreaks ranges from 50% to 100%. A recent paper in Cell that explores the bat's genome reveals how its immune system may prevent the virus from harming the flying mammals, which may hold clues for preventing or treating the infection in humans.
(more…)

instruction
Project to engage students in helping families with rare genetic diseases
Book Club Reader's Guide
Many challenging questions to stimulate thought and discussion.
Instructor's Guide
38 discussion questions to get students thinking and talking about gene therapy, including the science, ethical issues, and the drug approval process.
Narrative science
The Forever Fix is the uplifting true story of 8-year-old Corey Haas, who was cured of hereditary blindness just 4 days after gene therapy.
College Textbooks
A spectacularly-illustrated, clearly written human anatomy and physiology textbook, used in pre-health profession programs throughout the U.S.
A highly engaging, clearly written, beautifully illustrated introduction to the science of human genetics for the non-scientist. Now in its 11th edition, 12th to be published in September 2018.
Nonfiction
An ideal starting point for anyone who wants to know more about genes, DNA, genomes, and the genetic ties that bind us all.

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