Genetics

Polymorhpism Genetic Mutations



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Genetic mutations are a part of life. Without them, there would be no life, because when incipient forms of DNA copied themselves the resulting two copies would always have been exact replicas of each other. Therefore DNA would never have evolved all the varieties we have of it today. In nature this almost never happens. Almost every time DNA is copied, mistakes are induced into the process. The more complex the DNA the higher probability of single and multiple nucleotide misrepresentations. But when it comes to DNA, complexity can be a good thing.

Human DNA is divided into 46 chromosomes representative of about 3 billion nucleotides. The average gene consists of about 3000 nucleotides, and given that there are 25-30,0000 genes, no more than 90 million nucleotides are actively involved. The chance of a miscopy in an active gene is therefore 1 in 33, not very good odds. But what happens on that one out of thirty-three times when chance ends up causing an error?

Well, the first and most obvious fact, since genes code for proteins, is that that gene is not going to produce the right one any more. That could have some serious repercussions for the organism the derelict DNA belongs to. This is particularly true if the cell remains viable - able to make copies of its self- with the mistake incorporated into it. The severity of the impact is of course going to depend on the specific gene that is altered and the protein that it codes for. Keep in mind too, that there is only a 50/50 chance the gene modification will effect the host organism adversely. The modified gene could just as easily provide some advantage to the organism, but this article is only supposed to address the adverse effects not the beneficial ones.

Just about any infirmity associated with growing older, can be ultimately linked to a dysfunctional gene. In some cases, inactive genes can be switched on creating biochemical havoc, or active genes can be essential switched off having equally disastrous consequences. We have only just begun to understand all of the possible scenarios of what is going on with our genes. There is one condition that all to often results from gene mutations and that is cancer. Cancers are a perfect example of a gene or genes gone amiss. What is particularly troubling about cancer is that it is usually genes associated with cell division and growth hormone that are effected. As a result, a normal cell once mutated to become a cancer cell just starts making copies of itself on a mass scale, and the copies that are made do the same thing so that the cell mass begins to grow at an exponential rate. This can have a very adverse effect on the host organism.

We don't know yet for sure, but it may turn out that diseases like Alzheimer's and Parkinson's may be the result of polymorphism, and some protein imbalance which results from it. Indeed, many diseases if not most may be connected to genetic mutation. The good thing about this is that when we do learn how to fix genetic mutations, we may be able to relegate a lot of diseases to the history books. For now we just have to learn to live with them, or so we hope.

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