What's New in Life Science Research is managed and written entirely by Seed editors and expert guest bloggers. Read more about them This post was written by Dr. Hsien-Hsien Lei.
1. There are three main types of cloning - recombinant DNA technology aka DNA cloning, reproductive cloning, and therapeutic cloning.
2. The tadpole was the first animal to be cloned in 1952. Approximately 20 animals have been successfully cloned including sheep, goats, cows, mice, pigs, cats, rabbits, carp, and dogs.
3. Cloned animals suffer from a number of problems. The Human Genome Project cloning fact sheet mentions immune system deficiencies, greater susceptibility to infection, tumors, premature death, abnormal size or growth, abnormal gene expression. A 2006 Time article by Alice Park looks into the perils of cloning. The FDA, however, says it's a myth that "cloning results in severely damaged animals that suffer."
4. There are many benefits to cloning including creating models of disease, generating stem cells for research, and producing herds of bioengineered animals that can produce drugs. If cloning humans were ever possible, advocates claim it would also be a cure for infertility.
5. You could be eating cloned food in the future. In January, the FDA announced that cloned animals, their offspring, and cloned animal products such as milk and cheese are acceptably safe to eat. Cloning could also make the rare and valuable truffle regular dinner fare. The French have embarked on a project to culture cloned black truffles which are currently worth $1000 a kilo.
6. According to the FDA and other sources, cloning is NOT genetic engineering because cloning merely duplicates DNA but does not alter the DNA sequence. (Hmmm, I'm not sure about this one.)
7. Alert Einstein tops the list of who should be cloned in a survey of a thousand people. Others on the list include Jesus, Mozart, and Elvis. In reality, if human cloning were commonly available, I would think most people would probably choose to clone a loved one rather than clone public figures or celebrities.
8. "The cloning of humans is on most of the lists of things to worry about from science, along with behavior control, genetic engineering, transplanted heads, computer poetry and the unrestrained growth of plastic flowers." ~Lewis Thomas (via QuotationsBook)
9. My favorite novel about cloning is Kazuo Ishiguro's Never Let Me Go. For more, see this list of books and stories about cloning human beings.
10. My favorite movie about cloning is the comedy Multiplicity starring Michael Keaton as a father who wants to be everything to his family but still wants personal time to play. Other movies about cloning include: Jurassic Park, The Island, and Star Wars: The Attack of the Clones. For more, see Biotechnology Australia's study of human reproductive cloning in the movies.
Comments
Why are you not sure about #6? Cow meat is cow meat, same structure, same chemical composition, same genetic sequence in each cell. Why does it matter if the cow originally came from an egg cell or a skin cell?
Posted by: Coturnix | December 10, 2008 2:32 PM
I'm curious about #6 as well. While you could certainly alter the DNA during cloning, that's really a separate operation. I suppose there also exists the chance of accidental genetic drift, and the potentially different mitochondria, but I don't think either of those would make it a subset of genetic engineering. Bio-engineering, sure, of which genetic engineering is definitely a subset. Unless I'm missing something, which is a distinct possibility.
Posted by: Fargo | December 10, 2008 3:58 PM
Re: #6, I had not considered before that cloning was not genetic engineering. To me, the idea of genetic engineering is manipulating DNA in any form. And even if cloning is supposed to be a direct duplication of DNA, clearly the transfer of nuclear DNA results in other alterations to the DNA even if the bases remain the same.
Posted by: Hsien Lei | December 10, 2008 9:02 PM
RE: #1. There is no "therapeutic" cloning. Researchers may hope to develop therapies, but none exist. Call it cloning research.
RE: #3. The problems with the health of cloned animals is not a "myth". The FDA seems not to have read the papers it cites in its risk assessment.
Dr.Chavatte-Palmer, who is a research leader at the French government's Institut Nationale de la Recherche Agronomique, the leading agricultural-research institute in Europe has documented that only one half of one percent of cloned animals are born alive. (She is the researcher most quoted in the US FDA cloning risk assessment-58 times!) According to Chavatte-Palmer, most of clones miscarry due to genetic or physical defects or abnormal placentas. Their most common abnormality is called large offspring syndrome, which results in fetuses 20- to 85-per-cent larger than average.The animals that survive to birth also often have large offspring syndrome - which occurs in up to half of clone births - or other severe problems like a deformed head, contracted tendons, extreme diarrhea, diabetes, respiratory failure, heart disease and kidney problems. Many die shortly after birth. Of the animals that live past a few weeks, half die unexpectedly in the first 150 days.
Even the few clones that appear to be healthy really aren't. Chavatte-Palmer, who is one of the few scientists worldwide to have studied the long-term health of clones maintained in both her articles on cloning for the journal, Animales, and in the French risk assessment on animal cloning, that cloned animals are significantly different from conventional animals of the same species.
Health Canada in its comments to the US FDA regarding the draft risk assessment raised several issues, including the following:
� A definition of "normal" and addressing the question of whether clones are normal. Furthermore, there exists no formal baseline data on milk and meat from various livestock, similar to what is being generated for major crops, which could be used as a robust comparator.
� A baseline comparator for the outcomes of SCNT cloning as the information related to the animal health, food safety and composition of animals resulting from embryo splitting and blastomere transfer is not readily available in the published peer-reviewed literature and provide limited information as evidence of a history of safe use and as a baseline comparator.
� A study regarding longevity of livestock clones, from both an animal health and a food/feed safety standpoint. In addition, there is limited information from multi-generational studies.
� While some SCNT animal clones appear healthy and reach reproductive maturity, there is limited data on effects that may be more subtle and less easily detected, for example:
o aberrant expression of imprinted-genes
o effect of in vitro culturing conditions on cloned embryos
o alteration of cell cycle and mitotic spindle apparatus leading to chromosomal aberrations
o altered epigenetic control of gene expression
o aberrant expression of endogenous retroviruses
� More information on the potential toxicity, allergenicity and microbiological impacts should be presented, if available.
� Regarding feed safety issues, more information on rendering and other modes of disposal via the feed chain is required, if available.
There is virtually no long-term data on cattle and pig clones. The US FDA approved goat clones, but without any data. (I think they approved goat clones because one of the three FDA peer reviewers was a goat cloner.) The Europeans refused to approve goat clones due to a lack of data. Ironically, neither the US, nor the Europeans have approved sheep clones for food, despite the fact that the first animal cloned through somatic nuclear transfer was Dolly, a Suffolk sheep.
Most of the data that the US FDA looked at in its risk assessment came from two cloning companies. The largest study involved looking at the milk from 16 cloned cows. The average study had only five animals in the study. Pork was approved using data from only two studies involving only seven animals. Both of these studies were done by ViaGen, a Texas cloning company. There was only one studying looking at the toxicity of food from cloned animals and that study involved feeding 20 rats meat from one animal for 14 weeks. The reviewers concluded that the rats had a heighten immune reaction, but that the meat was not toxic, per se.
The FDA review says the offspring seem to be healthier than their clone parents because their genetic errors are "reset." They cite the work of Dr. Dean Betts for this conclusion, but his papers actually say the opposite. Betts found that the offspring of goat and sheep clones actually do have some of the genetic defects of their cloned parents.
In short, the health and effectiveness of cloning is still being challenged. Clones aren't "normal". They have been poorly studied with sample sizes that would not be accepted even for the approval of a new animal drug.
Your readers can look at our study on animal cloning "Not Ready for Prime Time" and related materials at: http://www.centerforfoodsafety.org/cloned_animals.cfm
Jaydee Hanson, Policy Analyst, Center for Food Safety
Posted by: Jaydee Hanson | December 11, 2008 5:41 PM