Alexander Gardner via Wikimedia Commons // Public Domain
Alexander Gardner via Wikimedia Commons // Public Domain

Did Abraham Lincoln Have a Genetic Mutation?

Alexander Gardner via Wikimedia Commons // Public Domain
Alexander Gardner via Wikimedia Commons // Public Domain

Abraham Lincoln's life has provided material for scores of historians. But one aspect of his history is being investigated by a very different kind of expert: geneticists. Lincoln’s appearance and medical history have some convinced that he had a condition called Marfan syndrome.

Marfan syndrome is one of a family of connective tissue disorders—that is, conditions that affect the glue that holds the body together. It affects many body systems and can be quite serious, but its most obvious signs are external: an unusually tall, lanky stature; and long limbs, hands, and feet—and if that doesn’t describe Abraham Lincoln, nothing does. 

The condition affects about 1 in every 5000 people, but because the syndrome is frequently inherited, many of the people who have it are related. And when one person is diagnosed, physicians frequently start looking at that person’s ancestry. Such was the case of a 7-year-old boy diagnosed in 1964. The diagnosing physician, a man named Harold Schwartz, had traced his patient’s family tree back more than 200 years, all the way to Mordecai Lincoln II, Abraham’s great-great-grandfather. 

Two years before Schwartz’s discovery, a doctor named A.M. Gordon developed a similar theory, which he published in the Journal of the American Medical Association. Schwartz added his new evidence to the academic literature, and the debate began in earnest.

Opponents of the theory argued that Lincoln had never shown any other symptoms of the condition. He had no heart problems, no lung issues, no eye trouble, and no overtly loose joints. He was 56 years old when he was assassinated, which would have been a pretty decent lifespan for anyone in those days. (Medicine has made great progress in its investigation of Marfan syndrome since Lincoln’s day. While there is no cure, the syndrome is treatable, and people who have it can expect to lead long, full lives.) And besides, the nay-sayers said, if Lincoln inherited the condition from his paternal great-grandfather, how do we account for his mother's looks?

This artist may have taken the resemblance a little too far. Painting by Lloyd Ostendorf via Wikimedia Commons // Public Domain

By most accounts, Nancy Hanks Lincoln was the spitting image of her son, with long limbs and a sad, melancholic face. A minister who was a friend of the family described her as “quite tall…bony, angular, lean…She had long arms, large head, with the forehead exceedingly broad … with chest sunken.” Nancy died at the age of 34, either from “milk sickness” or “wasting disease,” depending on which records you read. Whether there were other elements involved in her death, we’ll likely never know.

Her son is another story. Scientists discovered the gene associated with the condition in the 1990s, which suggested to them that genetic testing was possible, as long as you had a sample of someone’s DNA.

As it so happens, we’ve got that. Historians have preserved a number of grisly artifacts from the night of Lincoln’s assassination, including locks of hair, skull fragments, and even his blood, which soaked into his surgeon’s shirt sleeves.

Once scientists realized that they could potentially test the former president's DNA, a second question arose: Should they? In the 1990s, the National Museum of Health and Medicine created a committee of geneticists, lawyers, and forensic scientists, and left the decision up to them.

Those in favor of proceeding argued that, as an American hero, Lincoln could be a beacon and an inspiration for people living with the condition today. Addressing the committee, one person with Marfan syndrome said, “The fact that Lincoln may have had Marfan syndrome shows those of us that we too can contribute something of value to society … It’s time that all people, especially medical ethicists, realize that having the Marfan syndrome is not shameful, it’s just darned inconvenient.”

Those against emphasized how private Lincoln was in life, and stressed that to conduct medical tests on him without his consent would be a huge invasion of that privacy.

The committee eventually decided that, had he been alive, Abraham Lincoln would have consented to testing if the results could have helped other people. Unfortunately, their decision was moot. Additional Marfan-related genes had been discovered during their deliberations, and a definitive diagnosis would not really be possible.

Did Abe Lincoln have Marfan syndrome? We still don’t know for sure. But even without an answer, the debate about Abraham Lincoln’s appearance continues to raise public awareness of a condition affecting thousands of Americans.

Courtesy of Nature
Scientists Create Three Puppy Clones of 'Snuppy,' the World's First Cloned Dog
Courtesy of Nature
Courtesy of Nature

Snuppy, the world's first cloned dog, died in 2015, but his genetic legacy lives on. As the National Post reports, South Korean scientists recently described in the journal Scientific Reports the birth of three clone puppies, all of which are identical replicas of the famous Afghan hound.

Those who lived through the 1990s might remember Dolly, the Scottish sheep that gained fame for being the very first mammal to be cloned from an adult cell. Following Dolly's 1996 cloning, scientists managed to replicate other animals, including cats, mice, cows, and horses. But dog cloning initially stymied scientists, Time reports, as their breeding period is limited and their eggs are also hard to extract.

Ultimately, researchers ended up using somatic cell nuclear transfer (SCNT) to clone a dog, the same method that was used to make Dolly. In the early 2000s, a team of South Korean scientists inserted DNA harvested from an Afghan hound's skin cells into a dog egg from which the DNA had been removed. The egg divided, which produced multiple cloned embryos.

The scientists implanted 1095 of these embryos in 123 dogs, an exhaustive initiative that yielded just three pregnancies, according to NPR. Of these, Snuppy—whose name is a combination of "puppy" and Seoul National University's initials—was the only survivor.

Snuppy died from cancer in April 2015, just shortly after his 10th birthday. To celebrate his successful life, the same South Korean researchers decided to re-clone him using mesenchymal stem cells from the dog's belly fat, which were taken when he was five. This time around, they transferred 94 reconstructed embryos to seven dogs. Four clones were later born, although one ended up dying shortly after birth.

The tiny Snuppy clones are now more than a year old, and researchers say that they don't think that the pups face the risk of accelerated aging, nor are they more disease-prone than other dogs. (Dolly died when she was just six years old, while cloned mice have also experienced shorter lifespans.) Snuppy's somatic cell donor, Tai, lived just two years longer than Snuppy, dying at age 12, the average lifespan of an Afghan hound.

Researchers say that this new generation of Snuppys will yield new insights into the health and longevity of cloned animals. Meanwhile, in other animal cloning news, a Texas-based company called ViaGen Pets is now offering to clone people's beloved pets, according to CBS Pittsburgh—a service that costs a cool $50,000 for dogs.

[h/t National Post]

Researchers Pinpoint the Genes Behind the Durian's Foul Stench

Durian is a popular fruit in parts of southeast Asia. It's also known for having the most putrid, off-putting odor of any item sold in the produce section. Even fans of durian know why the fruit gets a bad rap, but what exactly causes its divisive scent is less obvious. Determined to find the answer, a team of researchers funded by "a group of anonymous durian lovers" mapped the fruit's genome, as reported by the BBC.

The study, published in the journal Nature Genetics [PDF], contains data from the first-ever complete genetic mapping of a durian fruit. It confirms that durian's excess stinkiness comes from sulfur, a chemical element whose scent is often compared to that of rotten eggs.

Analysis of the fruit's chemical makeup has been done in the past, so the idea that sulfur is a major contributor to its signature smell is nothing new. What is new is the identification of the specific class of sulfur-producing genes. These genes pump out sulfur at a "turbocharged" rate, which explains why the stench is powerful enough to have durian banned in some public areas. It may seem like the smell is a defense mechanism to ward off predators, but the study authors write that it's meant to have the opposite effect. According to the paper, "it is possible that linking odor and ripening may provide an evolutionary advantage for durian in facilitating fruit dispersal." In other words, the scent attracts hungry primates that help spread the seeds of ripe durian fruits by consuming them.

The revelation opens the door to genetically modified durian that are tweaked to produce less sulfur and therefore have a milder taste and smell. But such a product would likely inspire outrage from the food's passionate fans. While the flavor profile has been compared to rotten garbage and dead animal meat, it's also been praised for its "overtones of hazelnut, apricot, caramelized banana, and egg custard" by those who appreciate its unique character.

[h/t BBC]


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