Model organisms
Model organisms are organisms used in the study of genetic fundamental processes, serving as models for certain species and being studied by a community of scientists. One of their main characteristics is that they own some features that make them easy to be used in genetic experiments and can be breed in laboratories. Using them, there can be obtained information about species that cannot be studied directly (like humans). They have a simple structure and they are used to study basic phenomena in biology, which is hard to be observed in advanced organisms. Each of them has their own advantages and disadvantages, which make the researchers choose one or another depending on the purpose their study rely on.
There are some criteria used in order to select the model organisms from the living organisms. They might have short life cycles and fast development, so the transformations can be easy observed on certain generations. They also should have a small size as an adult, which makes them easy to be raised in laboratories considering space and budget limitations. Another criterion is tractability, meaning the property of being easy to manipulate them. Usually, scientists work with different organisms, for making their findings more general and observing differences between them. They also use these model organisms as surrogates, by taking the experiments in a more favorable environment than the one in the studied system.
The observations of a particular phenomenon from biological studies of this species may be at least partially valid for the other species. Model organisms make possible to produce more simply studies that are difficult or impossible for technical or ethical reasons. One of the most important conside...
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... work as pieces of a common molecular machinery (the actions of a complex of physically interacting proteins or signal-transduction pathway).
The model organisms in the second category are used in developmental biology. They don’t have the genetic characteristics like the ones in the first category, but they also possess some other advantages (like being easily manipulated because of producing robust embryos – e.g. the chicken).
The genomic model organisms are the ones with a significant genome, having an important position in the evolutionary tree (the puffer fish has got the genome smaller than the human genome, but very similar).
Because the best system for the study of disease is humans, a new technology called induced-pluripotent stem cells has been discovered, offering the opportunity to study disease relevant human tissue that is specific to an individual.
The cells unique nature has scientists intrigued to do research with the focus of finding a way that these cells can be used to replace patients’ injured or diseased tissues. Advancement is made to all the three types of stem cells namely embryonic stem cells, adult stem cells in addition to induced pluripotent cells. Embryonic cells are the building blocks of an embryo that is developing, and can develop into almost all body cell types. Somatic cells are found in the body tissues. They renew and regenerate in healthy bodies. The third type which is induced pluripotent is genetically modified embryo cells from skin cells.2 Research on these cells are geared towards saving humanity; a noble course.
3 Leicht B. G., McAllister B.F. 2014. Foundations of Biology 1411, 2nd edition. Southlake, TX: Fountainhead Press. Pp 137, 163-168, 177-180,
Today, we as a society world wide have a new issue to deal with. Science has discovered the means in which to clone animals, opening a whole new discussion. Many people are inclined to say why would science even wish to peruse this method of research. Lewis Thomas says in his essay "The Hazards of Science"
Because stem cells are essentially a blank slate, scientists are theoretically capable of growing any human tissue cell. There is enormous medical potential in this. Stem cell research is the next step in advancing the medical field. It is comparable to the discovery of penicillin or the inoculation for smallpox.
Stem cell research began in 1956 when Dr. E Donnall Thomas performed the first bone marrow transplant (“Adult stem cells are not more promising,” 2007). Since that time, research has evolved into obtaining cells from a variety of tissues. According to stem cell research professors, Ariff Bongso and Eng Hin Lee (2005), “Stem cells are unspecialized cells in the human body that are capable of becoming cells, each with new specialized functions” (p. 2). Stem cells are in various adult tissues, such as bone marrow, the liver, the epidermis layer of skin, the central nervous system, and eyes. They are also in other sources, such as fetuses, umbilical cords, placentas, embryos, and induced pluripotent stem cells (iPSCs), which are cells from adult tissues that have been reprogrammed to pluripotency. Most stem cells offer multipotent cells, which are sparse...
Those who favour stem cell research are optimistic about the continued developments in stem cell research will open doors to many breakthrough discoveries in biomedical science. The scientific and ethical questions arise as rapidly as the reaching of milestones in stem cell research. There are two main types of stem cells, namely embryonic stem cells and adult stem cells. Adult stem cells are undifferentiated cells in our body. But they have restricted-range of cells that they can further differentiate. On the contrary, embryonic stem cells have the ability to differentiate into nearly two hundred cell types in the human body, called pluripotency. The process of harvesting embryonic stem cells involves destruction of embryos (Mooney, 2009).
Three of which can be a counterfactual account, a manipulability account, and a controlled experiment account (Millstein, 2006), but only the first two will be reviewed. For each of the three cases heritable differences in physical characteristics and differences in reproductive success can be seen (Millstein, 2006). With the counterfactual account, the heritable difference can be explained by saying that the differences in reproductive success do not occur (Millstein, 2006). Natural selection favors the counterfactuals because, if there were no heritable differences in characteristics among organisms in the population, then there would be no differences in reproductive success (Millstein, 2006). This would mean that natural selection had nothing to favor and all organisms would have the same genotype (Millstein, 2006). Referring to the manipulability account, if scientists would change the heritable differences in physical characteristics of the organism in a population, there would be a visible change of their reproductive success (Millstein, 2006). For example, in a population of beetles with varying abilities to withstand different temperatures, a new beetle genotype is introduced that can withstand a greater range of temperatures, and we would expect that the relative reproductive success of the other genotypes would decrease (Millstein,
In this experiment, Mendelain Models are observed. The purpose of the experiment is to understand how traits are passed from one generation to the other as well as understanding the difference between sex linked and autosomal genes. One particular trait that is observed in this experiment is when a fly is lacking wings, also known as an apterous mutation. In this experiment, we will determine whether this mutation is carried on an autosomal chromosome or on a sex chromosome. The data for this experiment will be determined statistically with the aid of a chi-square. If the trait is autosomal, then it will be able to be passed to the next generation on an autosomal chromosome, meaning that there should be an equal amount of male and
Drosophila melanogaster, commonly known as fruit fly, is mainly used as a human disease model organism for genetic analysis. It was during the 20th century that D. melanogaster was considered as the most significant model organism. D. melanogaster is small in size, and it has a short life span with a good reproduction rate, perfect for raising in large number and generation counts for genetics experiments. Additionally, it has a small genome which makes it easier for geneticists to keep track of changes in molecular level. Geneticists were able to uncover many human genetic diseases through the homologous genome of human and fruit flies. It started out with a small group of people led by Thomas Hunt Morgan at Columbia University. Many principles and rules of transmission genetics that are still being used in the generation of today were established in the laboratory of Dr. Morgan. Many animal models were being used before fruit flies. Using the whole-animal as a model set limitations to the types and amounts of experiments can be conducted. The use of Drosophila was able to led geneticists to overcome these limitations with tremendous promises in finding greater quality results. It was Frank Lutz, who wrote many papers on Drosophila, which introduced Drosophila to Dr. Morgan. Many experimental works on plants and animals were carried out on Drosophila instead. Through Drosophila, the discovery of mutation, recombination, relocation of chromosome, and many others were made possible. The cinnabar, cn, gene encodes an enzyme essential in the eye color formation of drosophila. It codes for the enzyme, kynurenine-3-monooxygenase, that is essential in the biological pathway of ommochrome for the brown pi...
Genetics has given us important results with regards to knowing why certain organisms and their expressions are the way they are and how some expressions are suppressed due to those particular expressions being recessive. The reason is because genetics is the study of genes and the effects of it to organisms.
The clone has many different meanings in the modern world. The past identified a clone as something that that was copied from an original item or product. The term “The real McCoy” is an allusion to a patented train system, which everyone wanted but they did not want to buy that specific one. Nowadays the clone is an animal that has an identical DNA sequence to the donor of the DNA. The reasons for cloning is as varied as there are definitions. Many people would like to have the perfect child. Others can only have a baby by using cloning processes. Some believe that clones should be raised for their organs thus eliminating waiting lines for transplants since you get a genetically identical organ. There are several examples of cloning today. Dolly was the most popular since she was the first publicly announced cloning success. She was “born” on February 23, 1997. Bacteria are another example of cloning. They reproduce asexually and are identical to the original cell. This is used to our advantage by splicing specific strands of DNA into such bacteria so they b...
According to Darwin and his theory on evolution, organisms are presented with nature’s challenge of environmental change. Those that possess the characteristics of adapting to such challenges are successful in leaving their genes behind and ensuring that their lineage will continue. It is natural selection, where nature can perform tiny to mass sporadic experiments on its organisms, and the results can be interesting from extinction to significant changes within a species.
In addition to this use of models, the natural sciences also use models to illustrate observations. When looking through a microscope one would need to model the cell or any such microscopic being, however it is impossible, as well as illogical, to grab wha...
Biogenetic engineering is the ability to change or modify a genome of an organism through the use of biotechnology. We use this in order to add a new gene to an organism that it would originally would not contain. This creates a better suited organism to adapt to any form of change it may have to deal with. Biogenetic engineering works by physically entering the organism’s genome and removing it and inserting the genome into another organism this allows the organism that had received the new trait to express the new code. The steps for genetic engineering is by first finding an organism that contains a trait that is desired, then scientist will extract the DNA, then once the gene has been extracted it goes through gene cloning, this is the process in which the gene is located and copied from the different of genes that had been extracted, and sometimes the desired gene will be modified so that it will be able to perform desirelly within the organism, the transgene, which is the new gene, will be inserted into the organism, once inserted scientist will allow for breeding in order to perfect the desired gene. Biogenetic engineering allows for the manual transport of genes from one organism to the next. The genes that we use for bioengineering are beneficial since we are able to perfect this genes for an unlimited amount of usage. Bioengineering also allows a single or a few desirable genes to be inserted into an organism rather than breeding which has at times undesirable traits that might not be as beneficial to the organism as the gene that is being inserted manually in bioengineering.