Reproductive Cloning - Benefit Or Curse?

The announcement in February 1997 of the birth of Dolly the sheep (1) startled the scientific world and shocked the public. Dolly was a clone - a complete genetic copy of her parent. Cloning a mammal from an adult cell had always been thought impossible. There had been speculation regarding the possibility of reprogramming an adult cell from its differentiated state to a primitive state of totipotency. But this seemed more the realm of science fiction than science.

There was a great outcry from many public sectors, including religious figures, ethicists, and politicians. Many people believed that cloning humans would be the final outrageous outcome of the very slippery slope created by the advent of Dolly, who in fact was a friendly, mild-mannered sheep. Many religious leaders believed that human cloning would be an abomination and cloning itself should be outlawed. The debate over cloning persists and is very much in the news.

The notion of human cloning immediately brings to mind well-known works of literature and film. In the dystopia of Aldous Huxley's Brave New World clones are created in vats and used to populate all segments of society. In the 2005 film The Island human clones are created to supply spare parts for wealthy individuals. The clones are fully functioning adults with hopes, wishes, and dreams. But they have no rights and are killed when needed by their respective hosts. The masses of soldiers in Star Wars represent the archetype of everything that is bad about clones. These clones are produced in huge quantities, apparently have no wills of their own, and are used for political purposes and warfare. The Star Wars Clone Wars are the fevered nightmare of opponents to human cloning.

But reproductive cloning could provide a profound benefit to families and individuals. In the United States at least 8% of women have had a medical office visit related to infertility. (2) More than 2 million men in the U.S. have been diagnosed with male infertility. More than 100,000 in vitro fertilization procedures are done in the U.S. each year. Many of these procedures are done with donated eggs and/or donated sperm.

Reproductive cloning would allow a couple to have a child genetically related to both parents. For example, the father would provide the cell to be cloned. The mother would provide the egg which would be fertilized with the nucleus of the father's reprogrammed cell. Similarly, reproductive cloning would allow single-sex couples to have a child genetically related to one or both partners, depending on the circumstances.

Clinical reproductive cloning will not be available, if ever, for many years. Much research needs to be done. The ethical, legal, and social questions regarding reproductive cloning are profound. As a society we need to continue to debate the issues and explore possibilities and alternatives. We need to do these things in advance of scientific developments.

(1) Wilmut I, et al: Viable offspring derived from fetal and adult mammalian cells. Nature 385:810-813, 1997

(2) CDC

David Lemberg, M.S. in Bioethics, Albany Medical College, May 2010
Consultant, Author, Speaker. Research interests - health care and health care policy, reproductive technologies, genetics and genomics, K-12 science education
Executive Producer, SCIENCE AND SOCIETY, http://scienceandsociety.net
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Gene Assembly: DNA Sequencing of Gene-Sized Fragments Using Primer Walking

Next Generation (Next-Gen) sequencing is a new form of technology capable of determining the sequence of DNA the size of a bacterial genome. Despite this capacity to sequence millions of bases, Next-Gen technology is not always efficient or cost effective. Sequencing smaller fragments of DNA is an example of this. Sometimes researchers prefer to sequence a single gene to determine function or fill in gaps left by the more advanced technologies. Primer walking is a common practice still employed for sequencing smaller regions of DNA. Capillary sequencers have improved the capability of sequencing DNA with faster times and longer base read lengths. However, the basic process of primer walking and gene assembly remains the same.

Isolating the DNA Fragment

The first step in sequencing a selected DNA fragment is to isolate the fragment from genomic DNA. Isolation is often performed by amplifying copies of the chosen region using PCR (Polymerase Chain Reaction). PCR produces copies of (amplifies) a region of DNA determined by smaller single stranded oligonucleotides called primers. The primers anneal to the start point on the forward strand and the start point on the reverse strand as amplification proceeds in both directions. Amplification by PCR produces millions of copies of a given region of DNA. However, it requires knowledge of the sequence before and after the region in order to select primers for amplification.

Researchers sometimes choose to sequence the DNA fragment (PCR product) directly. However, many researchers prefer cloning using a bacterial plasmid as an alternative.

Amplifying the DNA Fragment in a Bacterial Plasmid

Once the selected DNA has been amplified by PCR, it is inserted into a bacterial plasmid. The plasmid is a circular DNA molecule with known sequence. The circular DNA is broken with restriction enzymes allowing the unknown DNA fragment to be inserted. Most commercial plasmids contain universal sights from which researchers can select universal primers to sequence the inserted DNA in the forward and reverse directions. Capillary sequencers typically generate 800 to 900 bases for each primer for a single set of sequencing reactions yielding 1600 to 1800 total bases of data. This may cover the entire insert for smaller DNA fragments. However, genes are generally over 5,000 bases. Therefore, one set of sequence results would not complete the sequencing of the entire fragment of DNA.

Sequence Results Provide Templates for Primers

Gene assembly and primer walking involve using known sequence to select primers for additional sequence data. Using a result generated from a universal primer provides the sequence template for designing the next primer. The primer will likely be selected around the 700 base region for a result with 800 bases of quality sequence. The remaining 100 bases will allow overlap with the new generated sequence. Primer walking continues until the forward sequence results intersect with the reverse sequence results. A 5,000 base insert would likely need 5 to 8 results to achieve overlap between the forward and reverse directions. Researchers may sequence both the forward and reverse strands completely to provide the entire sequence of the double stranded molecule to confirm the accuracy of all the bases.

Software Assembles the Sequence Results

There are commercial software programs designed to assemble sequence results in the order of their overlapping regions resulting in a consensus sequence. Many of these programs use chromatogram data that allows base peak calls to be reviewed and corrected if necessary. The chromatogram is a view of the actual data showing the quality of peaks generated during electrophoresis. Some programs simply use the text of the base calls, but this does not allow as detailed a review of the results.

Doug Bintzler is the laboratory director for DNA Analysis, LLC. Michael Jordan is the sequencing director for DNA Analysis, LLC. The company provides DNA sequencing services and full gene assembly. DNA sequence results are fully reviewed and edited before and after assembly. For more information go the DNA Analysis website at http://www.agctsequencing.com.

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The Myth Behind the Genetically Modified Organisms - GMO

Genetic engineering, gene cloning and protein engineering has enabled humans to make changes in the genetics of an organism and such an altered organism is called a "Genetically modified organism."

Genes from different organisms can be combined and this is known as recombinant DNA technology, and the resultant organism is called as "genetically modified," "genetically engineered," or "transgenic organism."

GMOs are produced by gene cloning; a foreign gene is introduced in a new organism. The new protein gets into the new environment and gives a new expression which enables the organism to demonstrate new characteristics.

Every new technological advancement is initially focused on the benefit of the human kind but with the passage of time a lot of controversies get attached to it, same is the case with these GMO's. Initially they were focusing on the beneficial aspects but as the time passed and they were tested and trialed there negative aspects also got into the lime light.

Benefits like more food, better taste, reduced maturation time and more nutrient intake in plants, and in animals better yields in eggs, milk and meat and also early maturation time are associated with GMO's. Issues concerning health, ethics, intellectual property rights and society are also attached to the usage of these organisms.

Different conspiracies are attached with these organisms, whether they are good or bad for the human health? Some lobbies take it as an interference with the work of nature, disturbing the natural cycle might result in a serious disorder affecting human lives.

The presence of GMO's in the food chain might introduce new allergens in the body or might result in disturbing the natural immunity against diseases and other foreign bodies. As it has always happened that when we disturb the nature, it strikes back, that's when the human beings try to undo what they've done, but it becomes impossible.

Introduction of microbes into the plants to inject a foreign protein in their anatomy has resulted in countless advantages for the human kind, excessively increasing the production levels, bringing more prosperity to the farmers. But the example of BT cotton is evident in explaining the whole phenomenon, as in the beginning the yields of this particular variety were huge but as the time passed, and the pathogens developed immunity against the variety, the damages were devastating.

A lot of debate is happening on these organisms along with a lot more research. Presently the methods might not be perfected or are in the way to perfection that's why a lot of anti lobbying is going on. But to deny the fact that the use of these organisms has brought only problems for human kind would be wrong, because they have also helped a lot in saving many precious human lives.

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