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Ricki Lewis

Genetic Linkage

12 Alternative Facts of Human Genetics

January 28, 2017
Tags: alternative facts, Kellyanne Conway, history of genetics, Mendel, Griffith
I’ve always wanted to write about my favorite experiment in human genetics, but a news hook was elusive. Not any more! Thank you Kellyanne Conway for your intriguing concept of "alternative facts."

I’m writing the 12th edition of my human genetics textbook right now, so it’s the perfect time to browse through the pages and select a few turning points in time when genetic reality might have diverged, leading to different outcomes, if "alternative facts" were possible. But first, to illustrate how scientists reject hypotheses to reach a conclusion, a brief review of what’s been called "The Most Beautiful Experiment in Biology".  Read More 
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A Necessary Retelling of the Smallpox Vaccine Story

January 17, 2017
Tags: vaccine, smallpox, Edward Jenner, Donald Trump, RFK Jr, Autism, anti-vaxxer
People once feared that small cows would emerge from the arms of vaccinated people. Ignorance about vaccines persists.
A curious confluence of events unfolded January 10. Just hours before President Obama uttered the powerful “science and reason matter” in his farewell address, Robert F. Kennedy Jr. announced that the incoming president had tapped him to head a committee on vaccine safety.

RFK Jr. is not a pediatric immunologist nor an epidemiologist, but a vocal "vaccine skeptic". Although the PEOTUS dialed back on the purported appointment shortly after social media erupted, a tweet from March 28, 2014 clarifies the new president’s analysis of the history and science of vaccines:

Healthy young child goes to doctor, gets pumped with massive shot of many vaccines, doesn’t feel good and changes – AUTISM. Many such cases!  Read More 
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Gene Action Tracks an Autoimmune Disease: Systemic Sclerosis

January 5, 2017
Tags: systemic sclerosis, scleroderma
Systemic sclerosis (Ssc) is a rare disease in which collagen gloms up internal organs and toughens the skin into an armor of sorts. It's also called scleroderma, from the Greek for “hard” (skleros) and “skin” (derma). Ssc is autoimmune, not inherited, but a recent report in JCI Insight describes how gene expression profiling -- transcriptomics – can add precision to diagnosis, monitor response to treatment, and identify drugs that might be repurposed to target SSc.  Read More 
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Genetics Error in "The Man in the High Castle" Season 2?

January 4, 2017
Tags: The Man in the High Castle
What if the Germans and Japanese had won WW2?
I’ve just finished watching season 2 of Amazon video’s terrifying The Man in the High Castle, which depicts an alternate reality in which Germany and Japan won the second world war, with an atomic bomb taking out Washington, DC. I admit confusion over gaping plot holes and teasers, but I did catch enough of the dialog to suspect that genetic info about one of the families is wrong.

Thomas Smith, adolescent son of Obergruppenführer John Smith, has a form of muscular dystrophy. According to a footnote in Wikipedia, it is Landouzy-Dejerine syndrome, which I hadn’t heard of by that name but recognized its name today, facioscapulohumeral muscular dystrophy (FSHD). It is autosomal dominant – if you have it, so does or did one of your parents, unless you're a new mutation (about 30 percent of cases).

In a 10-second scene in the final episode, we learn that John Smith’s uncle had the disease, and that his two daughters must be carriers.

Well, no.

A dominant condition doesn’t have carriers. You have the mutation or you don't, although symptoms may occur later in life, in which case a person with the mutation is pre-manifest, not a carrier in the classic sense. Since Tom’s uncle had it too, presumably before the State murdered him, and the condition is rare, it must be inherited, not due to a new mutation. I can only reconcile these facts if John Smith has the mutation too but is non-penetrant – meaning he has the genotype but not the phenotype. I wonder what the Nazis, obsessed with purifying the gene pool, would do with that intel! Plus, Thomas has what appears to be seizures and he trips – not the upper body weakness of the disease.

I suppose the writers chose FSHD because it isn’t horrible, making it more horrible that the Nazis exterminate those who have it. When Thomas realizes that he’s not healthy, he mutters the mantras “I’m a useless eater” and “I'm defective.”

I won’t spoil the ending. But can anyone explain an inheritance pattern that has carriers and non-penetrance? Meanwhile, maybe the new showrunner for season 3 will take a genetics course. Read More 
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