Major Developments on Stem Cells
The fruits of genetic research have benefited millions of people. Arguably, no other field in science has had a more direct impact on the world in the last half-century. Humans have discovered the secrets of the human genome, reproduced vegetables and animals in labs, created a criminal database of DNA to match on crime sites. Why do the specific phenotypes of parents and even further relatives become inherited or not inherited by individuals, plants and even animals? This question has boggled the minds of great scientists over the past millennia. With this curiosity, spawned impressive theories about heredity, such as what can you inherit? Can you choose what to pass down to your children? Is it possible to create a human clone? The answer to all these questions lies in genetics.
What is genetics? How does it apply in current society?
Genetics is the study of heredity, how traits are passed down from one generation to another. The human race has learned over centuries that offspring display distinct qualities that correspond with either the mother or father, some cases both. Darwin’s early experiments in the 1800s with pea plants showed how if we could select two high-quality parents, the offspring would be filled with traits from both sides creating an equally or even more efficient generation of new pea plants. Genes are not only passed down throughout plants, but they are also passed down through animal reproduction as well. This is why we can see clear similarities in personality or facial features between parent and child, they inherit their parent’s genes, but what’s interesting is what we do with this knowledge. This article will consider the applications of genetics in modern society, the process of generating stem cells, and the future of genetics.
Dolly, a successfully cloned sheep, wasn’t the earliest example of successful animal cloning, there have been other cloned frogs, mice, cattle. The process that made all these clones possible is nuclear transfer, where the nucleus of an egg cell (which contains all the chromosomes) is removed and replaced by the nucleus of an embryonic cell from the animal being cloned. There are several other ways, including stem cells (cells that have the potential to grow into any other type of cell) where they would be injected with the desired animal’s genes and then the stem cells would start to grow required proteins for the organism to grow. In Dolly’s example, they used Adult cells (cells that haven’t formed into organs in animals) which are differentiated, meaning that they also have the potential to grow into any other type of cell. Adult cells require an embryo to facilitate the growth, therefore a de-nucleated egg cell is essential for cloning.
Human cloning is very restricted (in most countries illegal), but still isn’t that far stretch for humankind. The idea of harvesting embryonic stem cells to facilitate the growth of any organism seems much more worthwhile for an investment, this process is called therapeutic cloning. Stem cells show great potential for advancement in the genetic community, these types of cells are undifferentiated which means that they have the capability to grow into any other type of cell. Degenerative diseases like Parkinson’s or Alzheimer ’s have been uncurable until now, where stem cells can be used to replace destroyed tissue in human organs such as the brain.
Through therapeutic cloning, the nucleus of the patient’s cell is removed and fused with a donated enucleated egg, and charged with an electrical impulse to induce proper fusion. The egg then develops into an embryo that has the exact same genome as the patient cell, which has a zero rate of rejection because the stem cell grows into the exact same cell as the patient.
Researches managed for the first time to successfully revert adult somatic mouse cells to pluripotency, meaning the cells could change to any other cell type, these type of stem cells are called pluripotent stem cells (iPS). How exactly do we generate stem cells?
There are a variety of ways to create stem cells, from “reprogramming ” adult cells to induce a stem-cell state (called pluripotent cells, or iPS cells) to extract them from human embryos. Currently, scientists are working on producing iPS (induced pluripotent stem) cells from skin cells, by add back necessary genes for growth and erasing the pattern in the skin cell (once a cell matures, the genes are “turned off” which means the cell doesn’t grow anymore). There are four common genes that are normally brought into the cell: Oct4(octamer-binding transcription factor 4), Sox2(sex determining region Y-box 2), Myc (Proto-Oncogene C-Myc), Klf4(Kruppel Like Factor 4). These four growth genes would be introduced back into the cell by viruses, it seems most efficient because viruses stick to a cell and insert their own genetic makeup into the cell, which then reproduces the virus that was filled with growth genes. This process would produce induced pluripotent stem cells that could grow into any type of cell, but even though it has shown great potential there is still a significant amount of research to be done. 20% of mice have died due to cancer caused by one of the added genes, showing that there is a big risk factor, at the moment iPSC technologies are too immature to replace the need for embryonic stem cells in research. With harnessing the embryonic stem cells, we can increase research much faster with the use of embryos as a source for stem cells, therefore require the sacrifice of embryos. Once this process is fully developed it will affect millions across the world with cures to several degenerative diseases.
Bioengineering these types of cells to be implanted in cloning methods has a tremendous impact on society, there have been so many successful examples of how gene editing in animal cells has provided benefit to humans. Sheep and goats have been genetically engineered to produce human proteins in their milk, such as clotting factors to treat blood disorders like hemophilia. Scientists have altered the genetic makeup of mice to be obese or develop specific diseases to allow scientists to study related disorders in humans. Not only does genetic engineering help in experiments, but when it comes to preserving biodiversity, we see many scenarios where the biodiversity of an ecosystem is threatened by recovered with careful cloning. The first successful integration of an endangered species into the wild was with an Asian Gaur in 2001 using a domestic cow as a surrogate mother. There have been cases with well-preserved tissue exists, cloning has also been discussed as an option for bringing extinct species back, the only problem is how tissue naturally degrades very quickly after an organism dies.
One in 10 people have Alzheimer’s, there are 60,000 annual American victims of Parkinson’s disease, the world has so many more degenerative diseases that restrict so much of the population. Stem cell research shows a promising future towards cures for these conditions, so far we haven’t been able to cure degenerative diseases and most people with severe types of these diseases don’t survive very long. The potential these cells show will not only extend their life but also give them a chance to live a normal life without prejudice or limitations, where they could perform equally as well without so many challenges.
This story is part of advances in biological sciences, a science communication platform that aims to explain ground-breaking science in the field of biology, medicine, biotechnology, neuroscience and genetics to literally everyone. Scientific understanding has too many barriers, let’s break them down!