In a recent documentary published by National Geographic about the trails of the DNA, particularly in Africa, a lot of facts and correlations between races were discovered. The documentary focused on three races: the Africans, Europeans and the Asians. The researchers theorized that majority of humans in this planet have African origins, at least by looking at their mitochondrial DNA and Y chromosome structures. This paper will focus on the different aspects of DNA; what is a DNA and why its journey is such a good one to follow.
Basic Information about DNAs
DNA is a type of nucleic acid located inside cells of living organisms. It is a very significant part of the cell although it is not classified as a cell organelle but a cell component. It’s a cell component that contains the genetic information of an organism. This genetic information is called genes (Pearson, 2006). DNA or genes are the primary hereditary materials that we could easily locate and study in humans and theoretically in almost any other type of organism.
The genes are primarily the reason why we see specific traits between individuals who originated from different families—more about this in blood lining. We see traits that are specific only to one organism and chances are that specific trait could not be found on other organisms. DNAs could be classified into two based on their location: nuclear DNAs and mitochondrial DNAs. Nuclear DNAs are DNAs that could be found on the nucleus of a cell while mitochondrial DNAs are the ones that could be found on the mitochondria of the cell. Y chromosomes are chromosomes that can only be found on males. The nucleus acts like the brain of the cell, controlling most of the chemical processes inside while the mitochondria is the primary cell organelle involved in the metabolic processes of the cell. It is also often termed as the powerhouse of a cell. DNAs are generally concentrated on the nucleus where it is stored via a coding system. The 4 chemical base systems is the one being used in coding. The 4 chemical bases we use are A, G, C & T which could be equated as Adenine, Guanine, Cytosine and Thymine, respectively.
Now, let us focus more on humans and their DNA. Some may often think about why all normal people (those who have no deficiencies and deformities) are born with two feet, two upper extremities, a head and a complete set of fingers on each limb. This could be explained by the similarities between a person and another person’s chemical bases. There could be up to 99 percent similarity between a person and another person’s chemical base (Jablonka, 2002). The remaining 1% is what makes us unique from other people.
The Trail of the DNA
The scientists who ventured into Africa followed the route that could possibly be the same route which the first modern people in Africa also followed some 50,000 years ago. They scoured for evidences as they follow the trail. The researchers hypothesized that all present humans are somewhat related to a woman whom they call “Mitochondrial Eve” and that this woman soon collaborated with a “Y chromosome Adam” (Shreeve, 2006). These two people existed in Africa some 150,000 years ago yet the scientists were still able to find a way to connect evidences from expeditions in Africa other evidences gathered from previous expeditions. This is what led them to that conclusion. However, there are other factors that they are still looking into right now. They believe that factors such as the Ice Age phenomenon some 13,000 years ago could have greatly contributed to the confusing patterns between a primitive man who came from Africa and a primitive man who was originally a Neanderthal.
During the ice age phenomenon, sea levels significantly decreased; the waters were continuously deposited inside huge glaciers. The sea levels became so low that primitive people were able to migrate from Africa to places as far as Australia and Asia through primitive watercrafts. The primitive people, driven by the fast-moving herds of game and other animals, even reached America some 45,000 years ago. African people started to occupy Asia and Europe. However, the researchers saw significantly more evidences of their existence in Asia. The scientists believe that this is because Neanderthals, at that time, occupy majority of the inhabitable places in Europe although this factor became negligible later on.
The one group of people who migrated from Africa to Asia was divided into two. There, they were able to find a larger social network and discover a wide variety of new tools. Later on, even the Neanderthals’ territories became squeezed as the number of immigrants increased. What’s unknown up to this point is the way how these people interacted with each other. Did they treat each other in a hostile way? Did they practice interbreeding? Did they look treat those new face as aliens beings? These things were the ones that the scientists could not uncover even with their latest DNA tracking and analyzing tools.
The strongest evidence that we could find that such process is continuously occurring is the presence of inherited traits of a child from his parents. Let us use humans as an example. Now if we are to take a look at the traits of a child aged as early as 2 years old (sometimes older); we could easily see that some of the traits of that child are either similar with that of her mother or father. This process is called heredity (Jablonka, 2002). It is the process where a trait is passed from one organism to another. The primary material involved in such process is the DNA. The child may have the same eye color with that of her mother (Sturn, 2004). There are a lot of laws and principles that have been formulated by our scientists as a result of continuous studies and researches. But what we should know is that the passing of traits from a parent organism to a new generation of organisms is a never ending process. This is why the scientists who followed the trail of the primitive Africans were still able to decipher something out of the very few evidence of existence that they were able to dig up.
It was indeed amazing how a single cell that contains genetic information could tell a lot of stories. Scientists were able to track down evidences that tell them that all humans up to this date have commonalities with the so-called Mitochondrial Eve and Y Chromosome Adam. It’s not only their DNA which travelled; the primitive people endured very long journeys from Africa to other continents of the world.
Sturn, R. Eye ColourL Portals into Pigmentation, genes and ancestry. Trends on Genetics. 2004.
Pearson, H. Genetics: What is a gene. Nature. 2006.
Jablonka, E. The changing concept of genetics. Annals of the New York Academy of Sciences. 2002.
Shreeve, J. The Greatest Journey. National Geographic. 2006.