12th edition of my human genetics textbook


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

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Genetic Linkage

Genome of Galapagos Gentle Giant Lonesome George Leaves Clues to Longevity

December 13, 2018

Tags: Sulcata, Lonesome George

Lonesome George
I have a special fondness for tortoises.

Many years ago I bought a baby Sulcata tortoise at a reptile show. Unbeknownst to me, as I brought the Oreo-sized Speedy home in a McDonald’s burger container, she could live 100+ years.

Speedy grew. Fast. For amusement, she took to moving the furniture around at night. The weekly bowel movement took me several hours to clean up and the culprit hated the bathtub. She loved being outdoors in the summer, a reptilian lawn mower, but come winter, she’d grow depressed stuck inside, stalling herself in a corner of my office like a misplaced file box.

I despaired. Then googling led to articles disparaging idiot northeasterners who take in the likes of iguanas and giant tortoises, then have to deal with the inevitable growth.

I had to rehome my beloved Speedy.

To continue reading go to my blog DNA Science at Public Library of Science, where this article first appeared.

Viewpoint: Putting CRISPR babies in context—learning from the past instead of panicking in the present

December 13, 2018

Tags: CRISPR, He Jiankui

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The birth announcement for the first human babies conceived using gene editing, to prevent an infection, came via YouTube on November 25.

In the words of researcher He Jiankui, of Southern University of Science and Technology in Shenzhen:

Two Chinese girls, who we’ll call Lulu and Nana to protect their privacy, were born healthy a few weeks ago. Their mother Grace started her pregnancy by regular IVF with one difference: right after sending her husband’s sperm into her eggs, an embryologist also sent in CRISPR/Cas9 protein and instructions to perform a gene surgery intended to protect the girls from future HIV infection. The surgery reproduces a natural genetic variation shared by more than 100 million people of primarily European origin that confers strong resistance to initial HIV-1 infection and disease progression.

Dr. He went on to briefly explain the safety measures taken: genome sequencing before the early embyros implanted in the uterus, during the pregnancy, and after birth. “These data indicate the girls’ genomes were changed as intended by the gene surgery, but no off-target editing or large deletions occurred,” he concluded, saying his team would publish the findings soon.

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


A Common Ancestry Metric Is Based On a Century-Old Discovery by a 19-Year-Old: CentiMorgans Explained

December 2, 2018

Tags: Ancestry.com, Sturtevant, centiMorgan

I’ve been immersed in genetic genealogy, following up on a recent contact from a relative I didn’t know existed. While trying to imagine scenarios that might explain how we came to be connected, I contacted Ancestry.com for assistance in seeing actual data. When I found the obvious drop-down menus next to my matches on the website, I was astounded to recognize the unit used to assess the closeness of relationships – a centiMorgan.

I’m sure that’s Greek to most people. But to a former Drosophila (fruit fly) geneticist like me, “centiMorgan” (cM) brought an instant meaning: distance along a chromosome.

Invention of the centiMorgan is one of my favorite tales from the history of genetics. It provided the very first genetic map, and inspired the variations on the theme that were to come, including full genome sequencing.

The intuition that has sent millions of people googling centiMorgans, with more to come after all those DNA kits are opened and spat into for Christmas, goes back to a sleep-deprived 19-year-old with a fantastically brilliant idea, 105 years ago.

To continue reading go to DNA Science, my blog for Public Library of Science, where this article first appeared.

Hiding in Plain Sight: Exploring Parkinson’s Link to the Appendix

December 2, 2018

Tags: Parkinson's disease, appendix, alpha-synuclein

Lurking in the layers of the human appendix lie deposits of alpha-synuclein, a protein prone to gumminess, like sticky rice. Known mostly for its clumping in the brains of people with Parkinson’s disease, alpha-synuclein aggregates found in the appendixes of healthy people made headlines a few weeks ago.

Isn’t the appendix fairly useless, even dangerous when inflamed? Is it also a gateway to a brain disease?

Actually, a link between the Parkinson’s protein and the appendix has been known for a few years. Now, new experiments reported in Science Translational Medicine confirm the connection and suggest a protective role for appendectomy. But rather than advising people to shed their appendixes, the researchers see their findings as opening up a new target for drug discovery for Parkinson’s.

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

The Coffee-Genes Story Brews Discontent on Thanksgiving

November 25, 2018

Tags: coffee

A few weeks ago a report claiming a love for coffee is “in the genes” fleetingly flashed across screens. I thought I’d let the grounds settle and then take a closer look, fitting with my writing about food every Thanksgiving (pumpkins last year, yo-yo dieting in 2016, and turkeys in 2015).

I keep a mental list of dumb things linked to genes.

Geno-Everything

“Get the giggles easily? Blame your genes: Genetic variant enhances how people react to funny – and sad – situations,” reported the Daily Mail, echoing a paper published in the journal Emotion. It refers to the long and short variants (alleles) of the 5-HTTLPR gene, which encodes the serotonin transporter. Variants of that gene are connected to whether participants laughed at Gary Larsen cartoons or not.

An article in The Telegraph, “It’s All In Your Genes: How DNA Explains Your Sense of Humor, Sleep Patterns, and Phobias,” explored arachnophobia, speculating about a genetic advantage handed down from an ancient aversion to spiders. The article links to another Telegraph article about a genetic connection to shopping style.

Soon I found myself sucked into a quagmire of British newspapers parroting each other, but not the technical reports. They evoke “in your genes” to cover quite a technological territory, including twin studies, comparing behaviors to having certain gene variants, to genome-wide association studies, to spinning stories that just make sense, like a fear of scorpions or not eating toxic bugs.

To continue reading go to DNA Science, my blog for Public Library of Science, where this article first appeared.



How Freddie Mercury Got His Voice: It Wasn’t His Teeth

November 16, 2018

Tags: Freddie Mercury

Shortly into the film Bohemian Rhapsody, Freddie Mercury attributes his magnificent voice to four extra incisors: “extra teeth equals extra range.”

The dental endowment had gradually pushed his front teeth forward, causing a great deal of teasing (“Bucky”) when Freddie was a boy and teen, then known as Farrokh Bulsara. He hid them behind his hand and, later on, a mustache. But it never squelched his singing.

The Internet is overflowing with accounts of the transplendent Rami Malek preparing for his role as the four-octave frontman by slipping on a pair of customized prosthetic upper teeth to practice speaking and singing.

While Freddie’s extra teeth were unlikely due to a specific genetic disorder, at least one group of researchers has suggested an alternate biological explanation.

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

If A Genetics Textbook Author Was Treated Like a Political Insta-Author

November 16, 2018

Tags: ghostwriting

Every week, it seems, yet another politician, or someone in a politician’s orbit, releases a book and lights up the media. Against a backdrop of ordinary people recording nearly everything, celebrities and politicians become insta-authors with the big publishers, raking in the huge advances.

Writing these tomes typically takes a few months, maybe a year. How can someone with a full time job do this? Does a politician wake up one day an accomplished writer, like me overnight becoming a proctologist, a plumber, or a porn star?

Political insta-authors often have help.

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

The Genomic Scars of Anti-Semitism

November 12, 2018

Tags: Kristallnacht, anti-Semitism

Tomorrow is the 80th anniversary of Kristallnacht, “The Night of Broken Glass.” On November 9 and 10, 1938, Storm Troopers, Hitler Youth, and civilians rampaged through Nazi Germany, shattering the windows of more than a thousand synagogues, Jewish homes, and more than 7,000 businesses, arresting 30,000 Jews and transporting them to concentration camps. Some say the event marked the start of the Holocaust.

The anniversary comes just 13 days after the massacre of innocents at the Tree of Life synagogue in Pittsburgh, a chilling reminder that the flame of anti-Semitism burns on.

History books and the media chronicle the hatred and misplaced sense of superiority that fuels destruction of a people, like the remembrances of Kristallnacht. But evidence also lies in our genomes. That’s the case for the Ashkenazi Jews, whose ancestry traces back to Eastern Europe, not so very long ago.

Continue reading at my DNA Science blog for Public Library of Science, where this article first appeared.

Celebrating National Sea Slug Day

November 4, 2018

Tags: sea slugs

I’ve just discovered that my birthday, October 29, is also National Sea Slug Day, so I thought I’d look into these creatures about which I know nothing, alerted by a news release.

A new 74-page paper in the Zoological Journal of the Linnean Society offers numerous photos, sketches, and electron micrographs of the animals, a type of marine invertebrate also known as a nudibranch (“naked gills”).

In the past, invertebrate zoologists have sorted out the 3,000 or so species of sea slugs by color patterns; whether the gills are elevated, vibrating, or neither; and the shapes of the jaw and the radula, a tongue-like structure with tiny teeth. The new paper adds DNA sequencing to the list of classifying criteria, which added 17 new species to the known 57 or so. All 17 are members of the vibrantly-colored genus Hypselodoris.

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

Not-So-Mad Scientists and Why They’re Making Human Body Parts

November 4, 2018

Tags: organoids

Halloween brings a cornucopia of candy body parts, so it’s a good time to review recent advances in organoid technology.

I’m missing a few body parts myself, so I have an interest in replacements that are biological: Mini-organs grown from stem cells. They’re even implanted with chips to record and send data, like this smart liver. Organoids more accurately model humans than do mice or monkeys, and can stand-in for experiments done on people. With that in mind, let’s take a look at some of the recent developments in this arena.

Mini-kidneys
Polycystic kidney disease affects about 12 million people, gumming up the intricate, highly symmetrically aligned tubules of the paired organs that filter 50 gallons of blood a day. Researchers from the Kidney Research Institute at the University of Washington describe their mini-kidneys, grown from human stem cells, in this issue of Nature.

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

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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