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Thursday, October 28, 2021

Column: Cloning Abe Lincoln, Part I

I stood six inches away from Abraham Lincoln’s DNA.

Last spring, I interned in D.C. – a shrine to Lincoln. I visited Ford’s Theater and gaped at Lincoln’s impressive memorial. But at the National Museum of Health and Medicine, my nose could almost touch pieces of the man himself: a lock of his hair, fragments of his skull and a handkerchief with his blood on it.

As I stood there, I wondered: could we clone Abe Lincoln?

Since Dolly the sheep was cloned in 1996, scientists have cloned mammals from mice to mules, but we’ve never cloned a human. Maybe it’s a gruesome desire, but if we ever decide to clone someone, I’d vote for Lincoln.

Before we start that debate (regarding celebrities and/or ethics), here’s how cloning works: First, scientists need a somatic cell from the original animal. A somatic cell is any cell that has a full set of chromosomes; this means sperm and eggs cells are excluded. Scientists then remove the nucleus – the part of the cell with the DNA – from that somatic cell. That nucleus is transferred to a donor cell that has no nucleus. The newly assembled cell is then implanted into the womb of a surrogate.

While this process sounds as straightforward as a Betty Crocker recipe, it is extremely difficult. The nucleus and its new cell might not be compatible. The embryo might not divide. The implantation into the surrogate might fail. After all that, the pregnancy might fail.

Cindy Batchelder, a postdoctoral scholar at the Primate Research Center at UC Davis, entered the field of cloning research just as the birth of Dolly made news. Batchelder made it her goal to produce the first cloned calf. The process took more time than she thought, and while she did produce some of the earliest clones, she didn’t meet her goal.

“I had imagined that it would be feasible to produce 20 or more cloned calves in a few years from the same donor animal,” said Batchelder. “In reality, the efficiency rate was so low that it took me five years to produce eight calves.”

It’s clear why we banish the thought of human cloning. With so much “sanctity of life” debate over stem cells and abortion, no scientist would dare experiment with a developing human fetus. But human tissue? That’s another story.

Cloning certain human cells – not entire humans – could solve the problem of tissue rejection. Transplanted organs are sometimes rejected by the host because the host’s immune system thinks the new organ is a threat. This mix-up happens because all cells have specific protein markers on the cell surface – when the immune system detects a foreign marker, it sounds the alarm.

Charles Nicolet, facility manager at the DNA Technologies Core and Expression Analysis Core at the UC Davis Genome Center, explained that cloning a patient’s cell would be a good solution.

“If you can generate tissues from your specific cells, then you get around the problem of rejection,” Nicolet said.

Nicolet said that scientists are already working with animals to clone “patches” of cells that can be used for transplants. He said that with the way the animal tests are going, we might see this technique in humans within the next five years.

With custom-grown organs on the horizon, it’s easy to skip past DNA experimentation going on today.

In 2006, President Bush sparked anti-genetic-modification outrage when he mentioned “human-animal hybrids” in his State of the Union Address. While I can’t help but picture centaurs or mermaids, the technology for inserting human genes into animal DNA is very real. It’s freaky, but it’s a good kind of freaky.

Alison Van Eenennaam, a specialist with the Animal Genomics and Biotechnology Extension at UC Davis, told me about several hybrid success stories. There was a goat that was engineered to produce a protein that treats blood-clotting problems in humans. There was also a cow engineered to produce antibodies to help immuno-compromised people. These human proteins and antibodies are microscopic; the animal is not a 50:50 mix.

“It’s still a cow. It looks like a cow – it’s not like it has a human head or anything,” Van Eenennaam said.

Now, back to Abe Lincoln.

After he was shot, his doctors and friends collected bits of his skull and bloody pieces of cloth as souvenirs of his autopsy. Locks of his hair were passed around like saintly relics. Long before they knew about DNA, these pieces of Lincoln represented the essence of the man.

While we do have remnants of his genes, we probably don’t have the entire DNA sequence needed for cloning. Sheryl Bernauer, lab supervisor for the DNA Sequencing Facility at UC Davis, said that when cells decay over time, the DNA is compromised. The DNA in Lincoln’s 145-year-old bloodstains and hair is probably useless for cloning.

“The hair itself would be very hard to get DNA from unless you have a complete follicle,” Bernauer said.

We don’t have any of Lincoln’s follicles, so that’s a no-go. Still, it’s interesting to think about how the development of cloning has changed the way we view human remains. Humans have always honored the dead, but now we know that – in DNA at least – part of the dead lives on.

I asked Nicolet, the scientist from the Genome Center, who he would clone if he could. He voted for George Washington.

“He was a cool dude,” Nicolet said.

Next week: It’s a nature vs. nurture showdown. Pretend we could clone Lincoln. What would his 21st century life be like?

MADELINE McCURRY-SCHMIDT also wants to clone J.K. Rowling. Rowling’s not dead, but come on, someone’s got to write more Harry Potter. That epilogue just won’t cut it. E-mail Madeline at science@theaggie.org.

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