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.

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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