Unidentified Gene Persuasive Essay
How do we know we know what each individual gene does? One way to investigate the function of a gene is to just remove the gene and analyze what happens to the organism. Let’s say we have a gene of unknown function in the human genome, an unidentified gene. First, compare it to other genes to see what similar sequences they have, if they code some similar sequences they might code for similar functions. However, if the gene the unidentified gene codes for something different we have seen before this approach might not be much help. Another way to investigate the function of a gene is to remove the gene and observe what happens to the organism. When the gene is removed from the organism’s genome the value and purpose of the gene could be decipher.
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So, how do we take away the unidentified gene from humans?
Well it is not possible to remove it easily or ethically properly. The next thing to decide is which model organism is appropriate to use. A model organism could be just any organism except human that could be researched in a lab. There many organisms to choose from but for these method scientists have decided that mice are the popular model to use. Reason being mice are mammals, 99% of similarity in genome to humans, are cheap, easy to raise and have a short generation time.
Deleting a gene or disrupting a gene function in a mouse is called conditional knockout mouse model. Conditional knockout mouse model is a refine strategy that has been developed to permit the inactivation of a gene of interest to a specific site, an organ or developmental stage. Having the ability to manipulate a specific gene at a certain time or tissue provides knowledge of the gene function as well as animal development mechanism. Making a knockout mouse is very complex but here is an overview of the process but of course there is different ways to do
it.
The first thing to do is create a targeting vector, which refers to targeting a specific area. In this case is to create a piece of DNA that can be targeted to the right place in the genome, the gene of interest. Take a portion of the mouse genome with the gene of interest incorporated since that the gene we want to knockout. To generate a targeting vector recreate the DNA at each side of the gene of interest, these strands are known as homologous. On the middle of the targeting vector is the area called the reporter gene. The general idea of this strategy is to replace the gene of interest in the mouse genome which will then be expressed instead of the original gene of interest. We usually select the reporter gene therefore it can also be called a selection marker. Also, there are other pieces of DNA called the negative selection markers which refers to the ability allocate the reporter gene if inserted in the wrong place in the genome other than the gene of interest locus.
Next, the target vector must be inserted into the mouse embryonic stem cells. Embryonic stem (ES) cells are special non-specified cells in an embryo that can differentiate into any cell type. This is a key concept because the genotype of these ES cells will be altered, essentially removing a specific gene from it. When the cells grow, divide and can differentiate all the daughter cells will be missing the gene of interest. The ES cells are growing in a Petri dish. Once the targeting vector is inserted into the ES cells it will undergo homologous recombination with the specific gene of interest. Homologous recombination meaning that the same pieces of
DNA will line up and recombine replacing the target gene with the reporter gene, not every cell will be recombined.
Subsequently, the ES cells that have been successfully recombined need to be identified. The reported gene and the negative selection markers from the targeting vector need to be examined in order to determine if the gene of interest has been knockout correctly, is considered a selection step. Now, that correct ES cells with the right genotype have been obtained they are injected into a mouse embryo. The ES cells that have been injected into the mouse are heterozygous from the knockout. In another words, one wild type copy of the gene of interest in one chromosome but missing the second functional copy of the gene of interest.
Additionally, this mouse embryo has both knockout ES cells and the original non-knockout ES cells, the embryo will grow up with both kinds. Then the embryo will be allowed to grow in a female mouse until birth. In order to get a mouse that is homozygous for the intended knockout the baby mice are taken for mating. When the mice have grown, mate and reproduced the offspring undergo different molecular methods to confirm the knockout mouse has been obtained. Once the knockout mice have been identified is taken for observation in all kinds of punitive or physical changes. The mice might not live to adulthood or live, might develop heart disease or any other kind of disease, might gain or lose weigh any changes observed will decipher the functions of the gene of interest.
The collection of interpretations of the conditional knockout mouse model will develop into a strong and efficient technique to dissect phenotypes, functions of gene mutations to create better models for human diseases. These can ultimately lead to a better understanding of human disease and eventually to cures.
So, how do we take away the unidentified gene from humans?
Well it is not possible to remove it easily or ethically properly. The next thing to decide is which model organism is appropriate to use. A model organism could be just any organism except human that could be researched in a lab. There many organisms to choose from but for these method scientists have decided that mice are the popular model to use. Reason being mice are mammals, 99% of similarity in genome to humans, are cheap, easy to raise and have a short generation time.
Deleting a gene or disrupting a gene function in a mouse is called conditional knockout mouse model. Conditional knockout mouse model is a refine strategy that has been developed to permit the inactivation of a gene of interest to a specific site, an organ or developmental stage. Having the ability to manipulate a specific gene at a certain time or tissue provides knowledge of the gene function as well as animal development mechanism. Making a knockout mouse is very complex but here is an overview of the process but of course there is different ways to do
it.
The first thing to do is create a targeting vector, which refers to targeting a specific area. In this case is to create a piece of DNA that can be targeted to the right place in the genome, the gene of interest. Take a portion of the mouse genome with the gene of interest incorporated since that the gene we want to knockout. To generate a targeting vector recreate the DNA at each side of the gene of interest, these strands are known as homologous. On the middle of the targeting vector is the area called the reporter gene. The general idea of this strategy is to replace the gene of interest in the mouse genome which will then be expressed instead of the original gene of interest. We usually select the reporter gene therefore it can also be called a selection marker. Also, there are other pieces of DNA called the negative selection markers which refers to the ability allocate the reporter gene if inserted in the wrong place in the genome other than the gene of interest locus.
Next, the target vector must be inserted into the mouse embryonic stem cells. Embryonic stem (ES) cells are special non-specified cells in an embryo that can differentiate into any cell type. This is a key concept because the genotype of these ES cells will be altered, essentially removing a specific gene from it. When the cells grow, divide and can differentiate all the daughter cells will be missing the gene of interest. The ES cells are growing in a Petri dish. Once the targeting vector is inserted into the ES cells it will undergo homologous recombination with the specific gene of interest. Homologous recombination meaning that the same pieces of
DNA will line up and recombine replacing the target gene with the reporter gene, not every cell will be recombined.
Subsequently, the ES cells that have been successfully recombined need to be identified. The reported gene and the negative selection markers from the targeting vector need to be examined in order to determine if the gene of interest has been knockout correctly, is considered a selection step. Now, that correct ES cells with the right genotype have been obtained they are injected into a mouse embryo. The ES cells that have been injected into the mouse are heterozygous from the knockout. In another words, one wild type copy of the gene of interest in one chromosome but missing the second functional copy of the gene of interest.
Additionally, this mouse embryo has both knockout ES cells and the original non-knockout ES cells, the embryo will grow up with both kinds. Then the embryo will be allowed to grow in a female mouse until birth. In order to get a mouse that is homozygous for the intended knockout the baby mice are taken for mating. When the mice have grown, mate and reproduced the offspring undergo different molecular methods to confirm the knockout mouse has been obtained. Once the knockout mice have been identified is taken for observation in all kinds of punitive or physical changes. The mice might not live to adulthood or live, might develop heart disease or any other kind of disease, might gain or lose weigh any changes observed will decipher the functions of the gene of interest.
The collection of interpretations of the conditional knockout mouse model will develop into a strong and efficient technique to dissect phenotypes, functions of gene mutations to create better models for human diseases. These can ultimately lead to a better understanding of human disease and eventually to cures.