Biomedicine – Part 9: Cloning

“Hello Dolly,” not the musical but the sheep. Seen below, Dolly was the first adult mammal cloning success using sheep.

Born in July 1996, Dolly was the first mammal known to be cloned from an adult of the same species.     Source: Farmers Guardian

Her journey from the petri dish to birth began as a cell taken from a mammary gland of a 6-year old female donor. The technique included putting the cell into a suspended state to extract its DNA. A host egg cell came from another female donor. With the egg cell nucleus removed the DNA from the mammary cell was inserted. Then an electric current was applied to simulate the energy accompanying fertilization and embryonic development. After 148 days, Dolly was born.

It wasn’t all that simple a task. The researchers tried this with 277 fused eggs. Only 29 embryos survived and of these 13 were successfully implanted, but only one, Dolly, was born.

Cloning is not new to nature, just new to humanity. Many creatures practice asexual reproduction, or parthenogenesis, producing exact copies of themselves. Many plants reproduce themselves by sending out roots laterally and sprouting exact DNA copies of themselves. Researchers studying Aspen trees in British Columbia, however, report that this form of cloning leads to an increasing likelihood of creating some bad genetic material. We call altered genes mutations. The scientists studying Aspens counted the accumulated mutations of 20 different male Aspen trees and noted that cloned trees were less hardy than their parents. The same can be said about Dolly. She aged prematurely and passed away after 6 years.

Dolly wasn’t the first vertebrate to be cloned. That honour belongs to a carp, cloned in 1963.

The first cloned mouse, named Cumulina, was created in 1997 and died in 1999.

Mira the goat, born in 1998, was actually 3 goats, all identical. Their DNA was modified so that their milk produced recombinant human antithrombin (rhAT), a protein that prevents blood from clotting.

Cow clones, made in Japan, appeared in 1998. Recently, a newspaper in the United Kingdom described some of the challenges related to cloned farm cows with reports of pain, ill-health, organ defects and gigantism.

The first cloned guar (an Indian bison) named Noah was born in 2000 and died 48 hours after birth.

Pig clones have popped up in the United States, the United Kingdom, Japan and other locations, the first appearing in 2000. In 2001 scientists produced the first pig clones genetically modified to grow organs suitable for human transplantation. This feat was accomplished by knocking out a pig gene that produces the coating on organs containing sugar molecules that trigger acute rejection when transplanted.

Talk about copycat, scientists in Texas successfully cloned a cat born in December 2001.

Joining all the above we have cloned dogs, rats, mules, horses, water buffalo, camel and a Pyrenean Ibex, a species of antelope that was declared extinct in 2000. Unfortunately in the case of the latter, it died shortly after birth and remains extinct.

Why Do We Want to Clone? – 10 Reasons. the Why and the Why Not

Cloning has great biomedical potential to help humanity tackle and cure diseases. In cloning animals we may yield enormous medical and agricultural benefits. But cloning also presents ethical challenges. The following lists the most commonly expressed reasons for cloning:

1. For medical research to create transgenic animals bred with genetic mutations that cause specific human diseases to study and find cures.

In 2009 a team at Seoul National University created the world’s first transgenic dog to model human diseases. The researchers cloned a red flourescent gene produced by sea anemones and inserted it into the dog genome producing Ruppy, a beagle pup who glowed red in ultraviolet light. A virus was used as the gene transport mechanism to introduce it into a cell nucleus. That nucleus was then removed and then inserted as a replacement nucleus in a dog egg cell. A few hours later the egg divided to become an embryo which was then implanted into a surrogate mother. The red flourescent gene serves no medical purpose other than a validation that this technology works. But currently the failure rate is better than 98% in taking altered egg cells and successfully producing cloned offspring that survive through pregnancy and birth.

2. For creating human stem cells, a perfect match from donors, banked and withdrawn when needed to insert into and repair damaged or diseased organs and tissue.

In October 2011, scientists at the New York Stem Cell Foundation Laboratory announced the first successful cloning of human stem cells to treat conditions such as diabetes and spinal cord injury. Researchers used a method similar to the one that created Dolly. The adult somatic cell source used came from skin. This field of study shows great promise.

3. Therapeutic generation of matched tissues and organs for transplant back into the donor.

Therapeutic cloning remains in the laboratory using animal studies with early successes treating neurodegenerative diseases like Parkinson’s, generating blood vessels and skin to deal with severe burns, producing endocrine cells to generate glucagon and insulin within a pancreas to cure diabetes, corticospinal axon regeneration to repair severed spinal cords, and photoreceptor regeneration to treat blindness.

4. For genetically engineering animals to generate life-saving drugs or proteins for use in humans.

In this area of research we are already seeing significant results. See my earlier comments about Mira the goat.

5. To create domestic animals with superior genetics by copying livestock with desirable traits.

Regarding genetically superior domestic breeding using clones, we have yet to prove we have mastery in this field. Today the success rate in cloning of less than 2% is very low. Cloned animals that make it to term tend to be larger than average. Called Large Offspring Syndrome or LOS, cloned animals with this condition have abnormal organs. Many have breathing and blood flow problems. Even normal-sized clones may experience kidney, brain and immune system health issues. Our early experience with adult cell nuclear transfer may be the reason why clones on average don’t live as long as normally bred animals because the nuclear material being used comes from an older donor cell. Our research shows that when normal human cells continually divide, the DNA sequences at the end of each chromosome shorten. The older the animal, the shorter the chromosome. We call these chromosome ends telomeres. Are the shorter telomeres affecting the lifespan of clones? Researchers continue to study the phenomenon because we have yet to see consistent outcomes in the DNA of cloned animals.

6.  To recreate extinct or copy endangered animals to restore biodiversity.

We may be closer to resurrecting an extinct species after some of the pioneering work done in the last decade. In 2008, researchers cloned a mouse from one that had been frozen for 16 years. Although the cloned Pyrenean Ibex died from defective lungs, the Spanish scientists who carried out this resurrection attempt showed us the potential for bringing back an animal from extinction.

From this pile of Woolly Mammoth hair and from marrow extracted from bones, scientists have reconstructed the DNA of this extinct Ice Age creature.

In Russia, scientists at the Siberian Mammoth Museum, in association with Japan’s Kinki University, have extracted marrow cells from a woolly mammoth and are planning to use an elephant egg cell as a host for cloning an animal that disappeared well over 10,000 years ago. Considering the failure rate in successful clone births the opportunity to recreate the mammoth will require a large enough sample to produce a successful baby and that is without consideration for other conditions such as the size of the animal in utero and the potential for birth complications for the surrogate mother elephant.

7. To duplicate a favourite pet.

If I told you TLC, the cable television channel, launched a reality TV program called “I Cloned My Pet,” would you believe me? It’s true. Just launched on January 11, 2012, each episode features a pet owner reminiscing about their animal friend who has passed on. The pet owner has saved locks of hair, or harvested cells and has sent them to a Korean laboratory offering pet cloning services. Scientists in South Korea have cloned dogs since 2005, not just for bereaved pet owners, but also to recreate highly prized working dogs. View the link to read about cloned airport security and drug detection dogs. This is big business in Korea.

8. To duplicate a dead child.

Although a positively Frankensteinian idea, in an article published in 2009, a fertility doctor claimed he had created 11 cloned human embryos made from adult skin cells and placed them in the wombs of four of his patients. In the same article the doctor claimed he created clone embryos of dead people, one of them a 10-year old girl. The attempt to reproduce the girl involved a sample of her blood. The doctor at the time claimed it was not his intention to actually bring the dead girl back to life.

Attempts at the United Nations in 2005 to create a worldwide ban on human cloning of this kind failed. Instead a resolution passed which stated “all forms of human cloning inasmuch as they are incompatible with human dignity and the protection of human life” should be condemned.

But if we can bring back an extinct animal then what is to stop someone, somewhere, from cloning a lost loved one?

9. To create a child for infertile couples and not use adoption or a surrogate.

If we can clone other animals then theoretically we can clone humans. In 2001, at the Human Therapeutic Cloning Conference in Rome, a consortium of doctors proclaimed they were in agreement on the question of human cloning as a medical treatment for infertile couples.  The agreement recognized that sterile men could pass along their genetic attributes to offspring only this way and should be given the opportunity. The scientists at this conference recognized that “the genie had already been let out of the bottle,” and better that they were the ones to do this then some “quack.”

10. To create a duplicate of an individual as an alternative to a surrogate for those who are not married but want an heir who is an exact match.

I recently visited a website called Clonaid. At first I thought this has to be a hoax. But Clonaid is real and claims its first human clone baby, named Eve, was born on December 26th, 2002. The juxtaposition of the date so close to Christmas made me even more skeptical.

Since 2002, Clonaid has made unverified claims that include four other clones including a second birth to a Dutch woman, and a third to a Japanese family who had their lost son cloned. Clonaid may be perpetrating a fraud but they are not alone in pursuing human clones. China’s Xiangya Medical College, in Changsha, is one of three research centres studying human cloning. In one Clonaid case the company described the desire of a homosexual couple who wanted to have sons, duplicates of themselves and that Clonaid was capable of fulfilling their wishes.

Indeed it seems that with Dolly the genie has been let out of the bottle and we are, at this point in the 21st century, wrestling with the demons that may follow.

Len Rosen lives in Toronto, Ontario, Canada. He is a researcher and writer who has a fascination with science and technology. He is married with a daughter who works in radio, and a miniature red poodle who is his daily companion on walks of discovery. More...