Cloning
Kinkajou : Cloning is a technology that everyone talks about without really knowing in what way it may change their lives. Everyone talks about cloning humans or sheep, but at the end of the day this is probably unimportant. Why spend heaps of time effort and money replicating people or animals, when they replicate just fine without any help? There is not a lot of evidence that any one human model is super special and that its’ widespread adoption would result in many improvements or benefits for the species.
Erasmus : I concur. I think animal cloning is important at the little end of town, not the big end. We already have a number of skills in controlling and directing cell line growth. These skills have been critical to our understanding of the real world.
For instance, look at the advances that have been made in understanding the immune system. Cell Cloning forms the basis of our understanding of the cells of the immune system. Our knowledge of the interleukins and cytokines that control the immune system are all based on cell cloning technologies. Common cell cloning techniques include use of: Transformed Cell lines, Fusion cells, and DNA vector inserts to cells. These have been critical in our understanding of cell growth and cellular communication. Cancer cell lines which are essentially naturally immortal cells have been cultured long-term, their properties studied, teaching us about control of cell growth, cell differentiation and cell mortality.
Cell Immortality via Transformation
Kinkajou : What are Transformed cell lines?
Erasmus : Researchers take EBV (glandular fever) virus and infect white blood cells, (obtained from blood samples). These cells are “transformed” by infection with the virus, and change their growth properties. The cells essentially develop immortal characteristics and can be studied, essentially forever.
One famous transformed cell line is the HeLa cell line. These are transformed cells from a woman with cervical cancer called Helen Lane. I think they still exist today, and can be obtained for study.
Cell fusions are based on a different process. Cell nuclei are fused together: not necessarily from the same species creating something else. Again this allows study of cell growth and cellular control mechanisms.
Kinkajou : I can see another consequence of what you’re talking about. The current research on cloning natural embryos has revealed the importance of telomere elongation as the mechanism for cell growth control and of longevity.
Baby Dolphin Cloning
Erasmus : Yes, an important point. If we can replicate cells and can alter their natural ageing process, we certainly have a foot in the door to prolonging human life. The consequences are enormous. The simple effect on the population, from having people living longer would be profound. All this research is of course targeted at the cellular level and cloning technologies and may well be critical in helping to find the key to cellular longevity enhancement.
The situation is more complex than just telomeres being the key for ageing. Humans have telomeres that age, yet humans are long lived. Rats have telomeres which age much less than those in human cells do, yet rats are short lived. Many human cells such as fibroblasts and other differentiated cells are deficient in telomerase.
Telomerase is responsible for reconstituting the telomeres at the end of the chromosome. Consequently, the deficiency in telomerase results in the telomeres at the ends of the chromosomes in differentiated cells to become shorter with every cell division. Yet length of telomeres does not correlate with longevity across species or cell lines.
There are other telomere effects. The protective proteins clustered around the telomeres progressively deteriorate as well. As the shortening of the DNA at the chromosome ends continues, cell cycle growth arrest occurs. We think this occurs based with a p53 dependent mechanism.
Dr AXxxxx : idiots! Don’t you realise if you substantially prolong life, you will substantially increase the population of the planet. You could easily end up with him population of 70 billion.
Erasmus : This situation becomes complex because human stem cells are thought to be immortal. They can regenerate and they continue to grow, replacing apoptotic somatic cells. Stem cell research promises repair or reconstitution of damaged tissues. Damaged nerve tissue in the spinal cord and islet cells in diabetes have all been suggested as possible targets for stem cell regeneration.
Kinkajou : The other thing I find interesting is that even though somatic cells age with mitosis, meiotic cells form the basis of immortality for the species. Although individuals age and die, the species goes on, potentially forever.
Erasmus : Interesting! Now in rodent cells (rats have been commonly studied), telomerase function is maintained as the cells proliferate. So the cells do not undergo mitotic senescence or ageing. However, when rodent cells are stimulated to proliferate in culture, a checkpoint mechanism is activated. (We believe the p19ARF gene sequence). So the cells age and die. Interestingly, DNA mutations at these checkpoints make it possible for rodent cells to proliferate indefinitely in culture without needing to undergo transformation. However, rodents age much faster than humans.
Disease Vs Genes in Human Longevity
Kinkajou : There are other suggestions about the basis of longevity. That doctor who invented the Paill Spectrum model says that the restriction of longevity is due to disease. Any attempt to increase life expectancy by manipulating telomere ageing mechanisms, is just likely to increase disease load, cancer and death. This suggests that all longevity prolonging strategies are doomed to failure in vivo (in the real animal), unless Paill Spectrum effects are negated.
Erasmus :Wow! That’s not the traditional view that the public press espouses on ageing. The public thinks that genetic science is the answer to all sorts of problems for disease and ageing. Genetics is not the answer to many problems in the Paill Spectrum model. Disease and its effects are the main agents involved in reducing life span and creating illness. If that’s right, there are a lot of idiots barking up the wrong tree.
Kinkajou : I can see some light already in the distance saying that genetics is not the answer to many things that the popular press espouses. The world is a complex place.
Erasmus :To date, there has been no genetic defect identified as cause for schizophrenia, mental illness and many cancers ( Though genetic changes are found in many cells). There are some specific genetic factors that may contribute to the development of these illnesses in some people, but there is no factor or factors that substantially predict or allocate causation to disease development. (There are some specific situations / cases where genes appear to “cause” some of these illnesses, but no situation or combination of these recognised factors is found in even the minority of affected or ill people.
Dr Xxxxx :The situation in cancer is very complicated. Cancer cells often do have genetic abnormalities. However, there is no underlying gene which causes these abnormalities to arise in the first instance. Many idiots out there proposed that single gene mutations are responsible for many diseases and cancers. However, many cancers have substantial chromosomal abnormalities. It becomes obvious that there needs to be a mechanism for chromosomal damage and chromosomal aberrations to develop and be allowed to proliferate. It is extremely unlikely that this is due to single gene mutations.
Human Hormone effects
Erasmus :I will comment on the issue of the development of atherosclerosis (known more commonly as heart or vascular disease). There is a perspective that 50% of the risk associated with the development of simple common cardiovascular disease is unaccounted for. This means that doctors can look at risk factors, but people with no risk factors still become affected and die, while people with lots of risk factors ( High BP, High Cholesterol, Diabetes, ) may still live without suffering cardiovascular events. There is obviously something missing in what we know.
Cloning Sheep Animals
Kinkajou : It becomes obvious that maybe cell cloning may help us to work toward some of these answers, if only to find that telomeres and genetics are not the answer to human longevity, illness and cancer.
The Paill Spectrum model certainly has something to say on the development of cancer. (I.e. It has an explanation as to how cancer cells evolve and even ties this process in with evolution.)
Darwinian Evolution in Cell Genetics
Interestingly, the Paill spectrum model says that monogenic evolution as championed by Darwin in his theory of evolution is bullshit. The situation is much more complex. Science claims that evolution is a random biomechanical event. Paill Spectrum says that there is still room for the belief of faith in the magic of the process. Evolution in this model is really a magic event.
Goo :Maybe both Science and God can work together. I have heard that evolution proceeds in a stepwise fashion not as a gradual sequence of changes. Paill spectrum appears to be a much better explanation for evolution than Darwin’s theory. (more information in this site)
Plants can grow in many ways
if you understand how to direct them.
Future Applications Cell Growth & Cloning Tech
Erasmus : I would like to mention another application of cloning and cell growth control skills in our consideration of ocean colonisation. If humans were able to control the growth of say mangrove cells in culture, we could probably build living boats able to serve as people’s homes. By reducing the recurrent overhead in building vessels, oceanic colonisation by the human race may well be possible. If we can grow our ships and if they self-repair and grow stronger with time, if we can gain access to their internal nutrient transfer systems (essentially the stem of the plant), we can build, grow, maintain and repair seagoing ships in a fashion that economically allows the human race to colonise the world’s oceans.
Kinkajou : Yes. I know some friends who work in air see rescue at the Gold Coast near Brisbane. The speedboats they use take a pounding in the ocean environment. They age and need to be replaced every few years, otherwise they could fall apart. Obviously an expensive process, needing to replace a vessel every few years.
Erasmus :Yes. To me the recurrent capital investment in the creation of oceangoing craft would seem to be an insurmountable barrier to oceanic colonisation.
Kinkajou : You’ve mentioned that possible future before. I think we’d need to know a lot more about genetics, cell growth, plant biology and organic biochemistry before that particular reality can even begin to take shape. It would take a lot of time, effort and money to get to a point where such an achievement is possible.
I mean Bill Gates pissed off a fair bit of money in trying to add extra nutrition to banana plants which form a staple crop for much of the world’s population, with very limited success. An excellent idea, but beyond our capabilities at this time.
Cell Growth Control Environment
Goo :I think the first step is acquiring tools and knowledge. Then we can move forward.
Erasmus : I did read about the attempt to add vitamins to the banana fruit. Hopeful! But no “fruit” to speak of so far.
Kinkajou : The nature of science is that you need to keep trying. I hope that they may one day succeed.
The term cloning actually covers a number of different activities. Cloning refers to a cell, group of cells, or organism that is produced asexually from and is genetically identical to a single ancestor.
Targets for cloning include:
- Plant cells : replicating new cultivars,
- Animals : Stem cells, cell growth research, cell differentiation research, cancer cell growth,
- Molecular : replicating DNA fragments,
Erasmus :Plants also have stem cells
Kinkajou : REALLY!
Goo :Yes you can find them in their stems.
Kinkajou : You have a sense of humour Goo.
Plant Animal Growth
Erasmus : Plants are different. Cloning is a common and natural form of replication for many plants. There have been some European grape cultivars which have been propagated asexually for over 2000 years. Plant grafting can be regarded as a type of cloning, as the new growth is essentially a copy of the original cells. Many plants form clone colonies naturally. For example, some succulents such as “mother of millions” lose pieces of stems. Once they reach the ground these pieces can develop roots and then proceed to develop into fully grown individuals. Some plants such as dandelions can also form seeds asexually, effectively creating plants with identical DNA.
The Cloning Technique: Molecular Level Cloning
In molecular cloning, DNA fragments containing gene segments are replicated. There are two main methods. DNA fragments can be factored into cells, which then replicate. DNA fragments can be attached to the promoter segments, and replicated with DNA polymerase. (The process can be used with RNA as well). Secondly, viruses can be used to carry DNA pieces into the cell.
Steps involved in DNA fragment cloning (in cell research) include:
- fragmenting and selecting DNA segments to replicate
- ligation: DNA segments are glued together in specific sequences, including a promoter segment
- transfer: inserting the new piece of DNA into cells
- selection: selecting cells that have the desired characteristics for study (much of the transfection process is random, with a variable success rate)
Cloning Plants
Animal cell cloning is used substantially to study cell growth and cell differentiation, to study the effects of genetic variations on cell growth, and to study the effect of mutations.
Clonal human blastocysts have been created.
Kinkajou : Not a particularly impressive achievement when most “normal” cells can do this automatically.
Erasmus :An achievement of sorts, because we can change the cells and study the effect of the changes on the growth.
Erasmus :To proceed however. Stem cell lines are yet to be isolated from a clonal source.
Dolly the sheep was cloned by method called somatic cell nuclear transfer (SCNT). Somatic cells with a full complement of cellular somatic DNA are selected. Maternal DNA is removed from a cell at metaphase II. The somatic nucleus is then inserted into the egg cytoplasm. This creates a one cell embryo. The new cell is exposed to an electrical charge activating cell growth. The cell develops into a blastocyst. Successful embryos are then placed in surrogate recipients. (Such as a sheep in the case of Dolly).
This is a difficult process. When Dolly the sheep was born, up to 277 eggs had been used for SCNT. 29 viable embryos were created. Three of these embryos survived until birth, and only one grew to adulthood. The procedure is manual and very time-consuming. In SCNT, mitochondrial DNA is not transferred. The original oocyte is the source of the mitochondria and the mitochondrial DNA. This could be important in cross species nuclear transfers, as nuclear- mitochondrial incompatibilities may lead to altered cell growth or even death.
It was initially claimed that Dolly the sheep had abnormalities resembling accelerated ageing. Speculation included that the telomeres at the end of Dolly’s chromosomes were shortened, hence causing growth abnormalities and early death. The scientists involved in cloning Dolly stated that Dolly’s early death was due to respiratory infection, and did not appear to be related to deficiencies or complications of the cloning process.
The process of growing an animal clone is called parthogenesis, (reproduction of an organism by itself without a mate).
Factors Controlling Cell Growth
Erasmus :
There are three main classes of factors that control cell growth.
- Mitogens stimulate cell division predominantly by altering intracellular negative controls that block the cycle of cell replication.
- Growth factors stimulate cell growth (an increase in cell mass) by promoting the synthesis of proteins and other macromolecules and/ or inhibiting their degradation of cell mass.
- Survival factors ensure cell survival suppressing apoptosis.
Growth factors are a distinct entity to mitogens and survival factors. However, many people use these terms interchangeably. Cell proliferation is a distinct process to cell growth (an increase in cell mass). During the process of cell replication, there are a number of checkpoints (also called restriction points) which will halt cell replication in specific circumstances. This can include triggering apoptosis (cell death).
Mitogens cell signalling can be complex. Erythropoietin is a mitogen causing cell division only amongst red blood cell precursors in the bone marrow. Platelet-derived growth factor (PDGF) is produced predominantly within megakaryocytes within the bone marrow and stored in the alpha granules of platelets. It is capable of stimulating growth in endothelial cells, fibroblasts, neuroglial cells, myoblasts (especially smooth muscle cell precursors) and macrophages. TGF-β (transforming growth factor) stimulates some immune cells and inhibits the growth of others. Also it can be stimulatory at some concentrations and inhibitory at others.
At some concentrations it can be stimulatory, while on the same cell type at other concentrations it can be inhibitory.