The Intricate World of Human Genetics

Have you ever imagined a world where you can look into your child’s eyes and know his/her genetic destiny? Or imagine a world where every facet of your child’s medical history, its strengths, and its vulnerabilities could be uncovered by tapping into a computer. Think about a situation where you can predict the exact number of years you will live or another in which an exact replica of a major organ in your body (maybe your heart or kidneys) can be transplanted if yours fail. No problem of rejection or transplant reactions. Welcome to the world of human genetics.

Today, we know more about how to build a human being than ever before. Since the human genome has been sequenced in June 2000, knowledge about this aspect of what makes us humans keeps increasing daily. The funniest thing about this science is that it revolves just around four alphabets of the gene – A, C, G, and T representing Adenine, Cytosine, Guanine and Thymine respectively. We are all made up of cells, the basic structural and functional unit of every human being. Deep inside the nucleus of each cell are some tiny fine strands (too small to be seen with the naked eye) interwoven together. These strands are the chromosomes, containing thousands of genes in all. The genes are also made up of the DNA, which carries the information which makes us what we are. Your genetic make-up determines whether you’ll have blue eyes or brown eyes, black hair or red hair, whether you’ll be tall or short.

Evolutionists have postulated that millions of years ago, that the earliest form of life was a single cell. During this period, the single cell multiplied by cloning, creating multiple identical copies of itself over and over again. There was neither diversity nor variation. It was just the same type of cell with the same genetic make-up. After some time, some sexual forms of life started evolving from some of these earlier cells deep in the ocean. It was these sexual forms of life that gave rise to the unique diversity we find today. Now, during fertilisation, a segment of DNA from each parent combines to form a zygote (offspring) which has the full complement of DNA. The offspring takes a little bit of each parent; takes the mother’s blonde hair colour and the father’s blue eye colour. Just a bit here and a bit there. This is what makes us unique and different from every other individual.

It has been established that the genetic information in our DNA is what determines our physical characteristics. How can we then use this information to predict what is going to happen to us in the future. The branch of genetics which deals with this is just in its early stages – the science of prediction. A recent research was conducted on some army recruits at the Army Training Headquarters, Bassingbourn, United Kingdom. About 100 recruits were used for the study. The recruits made almost perfect guinea pigs for the experiment because the effect of the environment on each of them was almost the same. They were all exposed to the same environmental factors – same food, same source of water, same amount of exercise, same number of sleeping hours, same training, etc. After several weeks of conducting the study, it was discovered that the ACE gene, located on chromosome 17 has two forms which determined athletic abilities. One version of the gene seems to be particularly associated with endurance capability and fatigue resistance of muscle while the other version seems to be particularly associated with strength capacity. Which one would you rather have, the strength form or the endurance form? The body muscles depend on oxygen for their metabolic activities. With the endurance form of the gene, the muscles are able to use less oxygen to produce the same energy than the strength form. This means that the muscles can survive longer periods of oxygen deprivation. This fact is more relevant in people having heart attacks. Whether such individuals would survive the attack would depend on which form of the ACE gene they carry. In the long run, our survival depends on this gene.

In another study, the thrill-seeking gene, D4DR, on chromosome 17, was found to differentiate adventurous people from non-adventurous people. With this gene, you can predict whether an individual would become hooked on drugs or go into extreme sports later in the future. The D4DR gene determines the release and effect of dopamine, a neurotransmitter in the deeper confines of the brain. When there is an increase in the release of dopamine, we feel excitement. Some people’s bodies are resistant to the actions of dopamine. This is what drives them to extremes in order to derive the same excitement that others derive with simple actions. This is also what makes someone to jump from a plane several miles up in the air (in the name of parachuting) or another to get addicted to hallucinogens, just to create an upsurge in dopamine release.

Can our genetic information predict who would become a criminal in the future? And on the basis of this information be able to nip these criminal intents in the bud. A landmark legal case took place some years ago. A man was driving home after work late one night. Suddenly, he felt the urge to stop in front of a shop. He walked up to the store clerk, demanded for all the proceeds of the day. After he had got this, he shot the clerk in the head. The clerk died. The defendant’s lawyer argued the case in a way that had never been done. He pleaded the court to allow the defendant’s genetic information be brought to the court and used as an evidence. He argued that the defendant had in his gene information that made him a criminal. He believed that deep down in his gene was a factor which made him commit the crime. The judge denied the admissibility of the evidence. At the end of the day, the defendant was sentenced to the death row. This case nevertheless brought about a lot of questions regarding the issue of criminality and genetics.

Studies like that of the ACE gene above have shown how much information can be gleaned from our DNA. But would you rather know that you would die a little bit younger because you possess the strength version of the gene? Or would you want to know as a 10,000km marathon athlete that you have the strength version, when your opponent has the endurance form?
The knowledge we have about genetics is much. Today, we know much more than we do years ago. And one thing is certain, in the years to come, we will be able to predict even more about our lives, because this world of prediction has already begun.

MARK TWAIN’S SATIRICAL INFLUENCE ON MODERN DAY SOCIETY

Samuel Langhorne Clemens (November 30, 1835 – April 21, 1910), better known by his pseudonym, Mark Twain, is a famous American writer and humorist, whose best work is characterized by broad, often irreverent humor or biting social satire. Twain’s writing is also known for realism of place and language, memorable characters, and condemnation of hypocrisy and oppression (“Mark Twain,” 2009). What does the word ‘satire’ mean? According to the Encarta English Dictionary (2009), ‘satire’ is the use of wit, especially irony, sarcasm, and ridicule, to criticize faults. As you follow along, you will see that Mark Twain, no doubt, had a lot of influence on the modern day society through his satirical writings.

Twain’s work was inspired by the unconventional American West, and the popularity of his work marked the end of the domination of American literature by New England writers. Twain was a master at rendering colloquial speech. He had a very important role in creating and popularizing a distinctive American literature built on American themes and language. His ability to accomplish a change in the literature also had an effect on the American reverence for European and British culture and all other things associated with it. So his satire has greatly influenced the course of history.

In his widely acclaimed masterpiece, The Adventures of Huckleberry Finn, he talks about a teenage boy by the name of Huck Finn whose father is an alcoholic. His father kidnaps him, but he manages to escape and together with a runaway slave, Jim, they sail down the Mississippi on a raft. Instead of turning Jim in, Huck goes against the society and makes a decision to help Jim break free from slavery. Through this adventure, Mark Twain focuses on three traits: racism, alcoholism and mob mentality. You know that Mark Twain has passed some valuable messages across, one of which being similar to a book judged by its cover (Quest4Glory, 2004). His messages have been the basis of most human right activists in our present day. For example, though racism was part of the story, yet the moral of the story remains clear: there is more to people than color, just like there is more to a book than its cover.

Also, Mark Twain, through his book The Gilded Age (1873), described the social, political corruption that has ravaged the American nation. And today, the period of the 1870s is regarded as ‘The Gilded Age’. This is one of the influences of Mark Twain’s satire on modern day society. Again, many writers, generations after his demise regarded Mark Twain as their major inspiration. Examples include Ernest Hemingway, William Faulkner, etc.

We can therefore assert that modern day society has been greatly influenced by Twain’s satire. You can see that his works have opened the eyes of the American people and that of the world to issues of racism, freedom, morality and self-definition in the society.

List of References
Mark Twain. Microsoft Encarta 2009 [DVD]. Redmond, WA: Microsoft Corporation.
Quest4Glory, 2004. Huckleberry - Satirical Plot. Retrieved June 27, 2006, from http://echeat.com

HOW IDENTICAL ARE IDENTICAL TWINS?

'Now, Clarice,' says Cora at last, 'you turn your lovely head to the right, so that I can see what I look like from the side'. [Mervyn Peake, 1911 – 1968].

We have all had experience with identical twins at one time or the other. Even you reading this article might be an identical twin. But are identical twins really identical? There has been a lot of research (twin studies) on the behaviour of twins, especially identical twins. It has been said that we are a product of nature and nurture, that is, every individual is a product partly of genetic influences and partly because of the environment in which he or she is raised.

According to the online dictionary, Wikipedia, Twins are two offspring resulting from the same pregnancy, usually born in close succession. They can be the same or different sex. Twins can either be monozygotic or dizygotic. Monozygotic twins are also colloquially referred to as identical twins and dizygotic twins as fraternal twins (“Twin,” 2009).

Monozygotic twins are derived when a single egg is fertilized to form a zygote which divides, as a result of mitosis, into two separate but identical embryos. Monozygotic twins are always of the same sex (except in rare cases of chromosomal defects). They also have the same traits and similar physical appearances.

We have always claimed that identical twins are identical right from their physical appearance down to their genome – DNA. A group of researchers from the University of Alabama, Leiden University Medical Centre and VU University, The Netherlands; and Uppsala University and Karolinska Institutet, Sweden recently published their findings. They studied 19 different pairs of monozygotic/identical twins. From their observation, they found differences in the CNV (Copy Number Variation) in DNA. CNVs (multiple copies of a single gene or absence of a set of coding letters in the DNA) were discovered only a few years ago.

According to Carl Bruder, PhD, and Jan Dumanski, PhD, of University of Alabama’s Department of Genetics (the study’s lead authors), “the presumption has always been that identical twins are identical down to their DNA,” “…that is mostly true, but our findings suggest that there are small, subtle differences due to CNV. Those differences may point the way to better understanding of genetic diseases when we study so-called discordant monozygotic twins...a pair of twins where one twin has a disorder and the other does not.” They also bring out the fact that while one twin might develop a particular disease, Parkinson’s for example, the other may not.

Apart from these findings, the effect of the environment must not be overlooked. While identical twins form with the same set of genes, human development is not purely genetic. There is the impact of the environment. For instance, while still in the womb, some monozygotic twins share placenta. A twin might get better share of the nutrients than the other. Also, the external world out there has its own influences.

There have been further studies carried out to verify the fact that identical twins are really identical. But the bottom line presently is that identical twins are not actually identical. And sooner or later, we would have to throw away those old biology texts.


List of References
Twin. 2009. Wikipedia 2009. Retrieved August 13, 2009, from http://en.wikipedia.org/wiki/Twin
University Of Alabama (2008, February 20). Identical Twins Not As Identical As Believed. Science Daily. Retrieved August 13, 2009, from http://www.sciencedaily.com¬ /releases/2008/02/080215121214.htm