A General Definition of Genetics - Research Paper Example

Table of Contents Outline Page Introduction 2 Genetics: A General Definition 3 Genetics: A History 4 Genetic Inheritance 6 Evolution and Genetic Mutation 7 Conclusion 8 Introduction The argument of nature vs. nurture is one of the oldest ones in the history of mankind. On one hand, there are those who wring their hands defensively, blaming all manner of dilemmas such as heart disease, obesity, drug addiction, alcoholism and even - in gross ignorance of the subject - academic dishonesty on their genes, claiming that such tendencies are hardcoded into their DNA. On the other hand, there are those who reject such a fatalistic notion, stressing that our own choices and upbringing matter just as much as, if not more than what is written into our genes. For many years this debate has raged, with both sides remaining more or less unable to agree on any one thing. However, one caring to conduct research into the subject will find that both viewpoints have some truth to them. For instance, there are those who are indeed genetically predisposed to such ailments as high blood pressure, diabetes and even cancer. However, while this means that they are more prone to contracting said killer diseases, the fact remains that their practice of good health habits - or lack thereof - will still be the deciding factor. Likewise, even one possessing genes for poor eyesight could compensate somewhat by taking better care of his eyes. To blame ones problems on genes would be the height of ignorance and irresponsibility. This being the case, it would definitely be worthwhile to explore the subject of genetics, the better to dispel such misconceptions on the subject. This research paper shall start by providing a general definition for the field of genetics, as well as the history behind it. The concepts of genetic inheritance, evolution and mutation shall also be discussed. All in all, the objective is to stress the point that while ones genes are very much influential in determining ones quality of life, such is not an excuse for irresponsibility when it comes to making life choices. Genetics: A General Definition The word genetics is equally derived from the Greek words for genitive and origin, while the field itself refers to the study of genes, heredity and variation in living organisms. Everything else falls under this heading, from the molecular structure of individual nucleotides and amino acids, to the behavior and inheritance of genes. Whatever the case, the most important thing to consider is that the offspring of any two people will contain a mix of traits inherited from them both (Griffiths et al, 2000). This can and has often been used to ones advantage, usually through the process of artificial selection, which refers to intentional breeding aimed at producing certain traits or a combination thereof. Unlike what happens in natural selection, one seeking to enforce artificial selection essentially goes out of his way to ensure that two organisms are made to reproduce in order to produce offspring in which the desired combination of genes is expressed. Such a practice dates back to over thousands of years ago, where people such as the Romans and the Spartans would discard misshapen, deformed or otherwise undesirable infants to ensure the purity of their people (Buffum, 2008). Similarly, farmers go out of their way to produce as much as possible each harvest, such that they will have more of the good crop to utilize as they wish (Wilczynski, 1959). From this, it can be said that having a healthy understanding of genetics and related concepts would be a major, major help, even and especially for laymen. If nothing else, one carrying genes putting him at risk for high blood pressure might be less than amused at passing his condition on to his children, and would likely be glad to know that there is, in fact, a way to prevent it from happening. Genetics: A History The field of genetics is a very interesting one indeed, and is useful to know about regardless of who or what one happens to be. Even wild animals have demonstrated at least instinctual knowledge of how this works, as exemplified by how the alpha male in a pack of wolves tends to have the most and best mates. The females in the pack see him as having the most optimal combination of traits, which they then want to pass on to their own offspring - something every parent will attest to regarding their own children. Students of this field have Gregor Mendel to thank for their understanding of the subject, given that much of the understanding available on the principles of heredity and inheritance can be traced back to his hybridization experiments on garden peas. He would later discuss these findings in a dissertation published in 1866, though his conclusions were met with much skepticism - some of it his own. It was only later on, after being rediscovered by three European scientists, that Mendels conclusions would see greater prominence (Henig, 2009). Directly succeeding and tempering Mendels concepts are the findings discovered by DNA researchers. Various notables would make breakthroughs during this period, beginning with the isolation of DNA in 1869, then of its nucleobases, then into its base, sugar and phosphate nucleotide units. This would further be expounded upon when, in 1957, the central dogma of molecular biology was posited - and was solidified only a year later (Meselson and Stahl, 1958). Last but not least came the concept of genomics, which served to further temper the above. Though word itself was coined by Dr. Tom Roderick of the Jackson Laboratory, around the same time the human genome was first mapped in 1986, genomics as a concept was first born when Frederick Sanger sequenced the genomes of a virus and a mitochondrion (Yadav, 2007). This was then followed by more achievements not only by Sanger, but by other pioneers as well, eventually culminating in the sequencing of Haemophilius influenzae - the first free-living organism to be sequenced - in 1995. And ever since then, even more living organisms have undergone the same process. As can be seen, the history behind the field of genetics is just as interesting as the concept of genetics itself. Much thanks is owed to the many great minds that explored the topic both to satisfy their own thirst for knowledge as well as to bring about the betterment of mankind itself, as it is their efforts that have empowered many others to devise ways to put to use what they have learned. Indeed, to say that life as we know it would not be the same were it not for Mendel and company would hardly be exaggerating. Genetic Inheritance As already noted, the process through which genes are passed down by parents to their offspring is a complex thing. It can and usually does happen that traits that have always been expressed prominently from generation to generation end up being conspicuously absent in one of the offspring, who may or may not end up being the oddball in the family as a result. Conversely, it is also very much possible for a particular gene to go unexpressed for generations in a row, only to appear much later on, and much to the surprise of everyone. Of the many theories on heredity, the tenets of Mendelian inheritance have always been the most well-known, and arguably the most consistently accurate as well. Summed up, Mendelian inheritance simply posits that inheritance depends on the genes inherited from ones parents, the combination of which may result in a particular trait being expressed or suppressed. Where a pair has at least one dominant gene, that particular gene will always take precedence; even under incomplete dominance this still applies, although in that case the recessive gene will not be completely suppressed. A pair consisting of two codominant genes results in a phenotype blending traits of both genes. And finally, recessive genes only fully manifest when a single pair comprises two such genes (Nussbaum et al, 2007). Depending on whether a particular pair consists of two dominant or recessive genes, or one of each, the trait in question may or may not manifest. And when one takes into account the related concepts of codominance and incomplete dominance, the possible resultant phenotypes become all but endless. Indeed, it is largely these concepts that gave rise to genetic engineering. Evolution and Genetic Mutation Our traits are all but hardcoded in our DNA, and are said to be unchangeable and immutable. However, this is not entirely true. Indeed, contrary to popular belief, certain external stimuli can eventually trigger such changes in our genes, which is where the similar but distinct concepts of evolution and genetic mutation come in. More often than not, traits tend to be complex, such that they are controlled by multiple interacting genes; in such a case, a change in one of these genes will be unlikely to alter the entire phenotype. Instead, changes to these genes will normally result as one adapts to a pattern of activity in a particular set of surroundings, in a process known as niche construction. As one continues to live in operate in a given location, so too will his body adapt to better suit this environment. For instance, those living in Africa tend to have bodies with a greater surface area, allowing them to deal with the intense heat that is usually the norm in the region (Wu and Lin, 2006). This particular observation lends credence to the view expressed earlier - that both nature and nurture come into play when deciding ones future. While it is true that ones genes are the biggest factor with respect to his phenotype, the influence of the environment - as well as of his own response to external stimuli - should also be accounted for. As a given trait becomes less and less relevant in a given population residing in a particular area, so too will it manifest with less and less frequency, until it eventually disappears entirely. Another way for change to be effected in ones genes is mutation, which in living things pertains to a change in the nucleotide sequence found in the genome brought on by damage to ones DNA or RNA. Unlike evolution, which describes a gradual change in ones genes over an extended period of time, mutation tends to happen more quickly and suddenly. And while many cases of genetic mutation have come about as the result of external stimuli such as radiation, it can just as easily happen that the cause of mutation lies within the body itself (Burrus and Waldor, 2004). The concept of genetic mutation has been subjected to many misconceptions as depicted in popular culture. For instance, contrary to popular belief, mutation does not necessarily cause one to become horribly deformed or disfigured, nor are they necessarily abnormal. Many mutations not only effect little if any observable change in ones phenotype, but also take place in processes such as the development of the immune system and even evolution itself. Despite the connotations of the word mutation, this phenomenon is not actually as unusual as one may think (Bertram, 2000). Nor are mutations necessarily harmful by definition. Indeed, mutations have been known to exist that grant the individual increased resistance to deadly diseases such as HIV and the bubonic plague. And in fact, such mutations are especially likely to become more common in a given population living in a particular area through natural selection. Just as genetic mutation is a lot more common than the connotations of the word may suggest, so too is it not nearly as harmful as it seems (Sullivan et al, 2001). Conclusion That genes account for a significant part of who and what we are cannot be denied. They dictate our basic physical appearance, as well as our compatibility with our environment in general. It can even be said that our genes decide our level of intelligence as well, given how this particular attribute tends to run in families to the point of being an occasional cause for argument. At the same time, however, the most our genes can do is govern our potential strengths and destiny. Game designer Hideo Kojima said it best in one of his works when he remarked that we must not be ruled by our genes - that we can choose the kind of life we want to live. And as pointed out in the film Gattaca, there is no gene for the human spirit. Between a person with a subpar genetic makeup but who was raised right, and someone with optimal genes but whose upbringing left a lot to be desired, the former will always be more likely to succeed. The important thing is to choose life, and then live. References Bertram, J. "The molecular biology of cancer". Mol. 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PNAS 95.18 (2001): 10214–10219. Print. Wilczynski, Jan Z., "On the Presumed Darwinism of Alberuni Eight Hundred Years before Darwin". Isis 50.4 (1959): 459–466. Print. Wu, R. and Lin, M. "Functional mapping – how to map and study the genetic architecture of dynamic complex traits". Nat. Rev. Genet. 7.3 (2006): 229–37. Print. Yadav, Satya P. The Wholeness in Suffix -omics, -omes, and the Word Om. J Biomol Tech. 18.5 (2008): 277. Print. Read More