12th edition of my human genetics textbook


Tags

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

Genetic Linkage

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.

Craig Venter’s Synthetic Genome 3.0 Evokes Classic Experiments

March 31, 2016

Tags: synthetic biology, synthetic genome, J. Craig Venter

Is a synthetic genome new life?
J. Craig Venter and his colleagues at Synthetic Genomics Inc update their efforts to create a “hypothetical minimal genome" in Science.

“JCVI-syn3.0,” or syn3.0 for short, is about 531,000 DNA base pairs organized into 473 genes, serially transplanted into cells of the tiny and fast-replicating Mycoplasma mycoides and M. capricolum. The first iteration of the smallest synthetic genome, JVCI-syn1.0, has just over a million base pairs, and the intermediate JCVI-syn2.0 has 576,000.

While syn3.0 will serve as a foundation for future synthetic biology, it reminds me of two favorite experiments from more than half a century ago. (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.

Quick Links