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Nottingham University

8 Years On, Dolly’s Clones Are Doing Just Fine

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Nottingham University

For many people, the word “clone” conjures terrifying images of a dystopian future. We worry about the moral and philosophical implications of creating genetic copies. Cloning scientists have concerns, too, although theirs are often more technical: is cloning harmful to the organisms it creates? In the case of Dolly the sheep’s cloned offspring, at least, the answer appears to be no. Scientists say the four eight-year-old sheep are just as healthy as other sheep their age. They published their findings in the journal Nature Communications. 

The world’s first cloned animal drew her first breath in 1996. Dolly’s birth was met with elation, outrage, and fascination—reactions that would follow her throughout her life. The world was watching when the sheep was diagnosed with osteoarthritis at the relatively young age of five. She died just a year and a half later, prompting concerns that the somatic-cell nuclear transfer (SCNT) process that brought her to life had also accelerated her aging, illness, and death. 

Five years later, a new class of clones entered the world. Debbie, Denise, Dianna, and Daisy had been copied from Dolly’s DNA using the same SCNT process. Would their lives go the same way as Dolly’s? Researchers could only wait and see. 

Debbie, Denise, Dianna, and Daisy (we're not sure which is which, but can you blame us?). Image Credit: Nottingham University.

The Nottingham Dollies, as the four new clones are called, sailed through ages one through seven without a hitch. When the clone club reached their eighth birthday (which equates to about 60 to 70 in human years), scientists decided it was time for a thorough checkup. 

They brought the Dollies and nine other cloned sheep between the ages of 7 and 9 into the lab and searched for signs of aging-related ailments. Researchers tested the sheeps’ glucose tolerance and insulin sensitivity, their heart rates and blood pressure, and the health of their joints. Their results were then compared with those from a group of the university’s naturally conceived sheep. 

Cloned or no, all the sheep were in pretty robust health for their ages. The researchers could find no signs of diabetes or hypertension in any of them. A few of the sheep, including Debbie, had mild to moderate osteoarthritis, but even this was less severe than Dolly’s, and she was younger when she died.

There’s still plenty of room for improvement in the SCNT process, lead author Kevin Sinclair said in a press statement. But he’s confident the process will improve, and that we’ll be able to use it to create stem cell therapies for people and healthy transgenic animals. “However, if these biotechnologies are going to be used in future,” he said, “we need to continue to test their safety.”

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Big Questions
Why Do Cats Freak Out After Pooping?
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Cats often exhibit some very peculiar behavior, from getting into deadly combat situations with their own tail to pouncing on unsuspecting humans. Among their most curious habits: running from their litter box like a greyhound after moving their bowels. Are they running from their own fecal matter? Has waste elimination prompted a sense of euphoria?

Experts—if anyone is said to qualify as an expert in post-poop moods—aren’t exactly sure, but they’ve presented a number of entertaining theories. From a biological standpoint, some animal behaviorists suspect that a cat bolting after a deposit might stem from fears that a predator could track them based on the smell of their waste. But researchers are quick to note that they haven’t observed cats run from their BMs in the wild.

Biology also has a little bit to do with another theory, which postulates that cats used to getting their rear ends licked by their mother after defecating as kittens are showing off their independence by sprinting away, their butts having taken on self-cleaning properties in adulthood.

Not convinced? You might find another idea more plausible: Both humans and cats have a vagus nerve running from their brain stem. In both species, the nerve can be stimulated by defecation, leading to a pleasurable sensation and what some have labeled “poo-phoria,” or post-poop elation. In running, the cat may simply be working off excess energy brought on by stimulation of the nerve.

Less interesting is the notion that notoriously hygienic cats may simply want to shake off excess litter or fecal matter by running a 100-meter dash, or that a digestive problem has led to some discomfort they’re attempting to flee from. The fact is, so little research has been done in the field of pooping cat mania that there’s no universally accepted answer. Like so much of what makes cats tick, a definitive motivation will have to remain a mystery.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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Animals
Listen to the Impossibly Adorable Sounds of a Baby Sloth
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RODRIGO ARANGUA/AFP/GettyImages

Sometimes baby sloths seem almost too adorable to be real. But the little muppet-faced treasures don't just look cute—turns out they sound cute, too. We know what you're thinking: How could you have gone your whole life without knowing what these precious creatures sound like? Well, fear not: Just in time for International Sloth Day (today), we have some footage of how the tiny mammals express themselves—and it's a lot of squeaking. (Or maybe that's you squealing?)

The sloths featured in the heart-obliterating video below come from the Sloth Sanctuary of Costa Rica. The institution rescues orphaned sloths, rehabilitates them, and gets them ready to be released back into the wild.

[h/t The Kid Should See This]

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