Response Paper For Traces of Distance Past

Both in the article that I read, titled Traces of Distant Past, and in the video that I watched, called Journey of Man, I learned about how scientists are able to use DNA gathered from different lineages, or groups of people, to construct a “genetic tree”. Geneticists spend a lot of their time traveling around the world, as seen in the video, and they do this in effort to gather as much DNA from as many different lineages as possible. By gathering DNA from multiple different lineages, both in different regions and from different ages, these geneticists can accurately create a “timeline” of human migration. Through this process, scientist has been able to trace the origins of modern humans back to a single African woman who lived close to 200,000 years ago. This woman, the common ancestor of all modern humans, is referred to be scientists as “Mitochondrial Eve”. Later in this article, I learned that Y-chromosomes are now used instead of mitochondria so as to better trace this human migration, since Y-chromosomes have more nucleotides; tens of millions, compared to just the 16,000 nucleotides in mitochondria. This newer approach allows scientists to better distinguish one population from another. As yet another approach, genealogists have used microorganism genes, such as bacteria, viruses, and parasites, to discover patterns in migration. They do this because these microorganisms hitched a ride on humans during their migration, so would have been exposed to the same places. Geneticists also study SNP’s, which stand for single nucleotide polymorphisms, and are swaps of one nucleotide for another. Researchers can use SNP’s to resolve the identities of individual populations. The studies of all of these different genetic variations serves to provide us with a kind of historical “Global Positioning System”.

I found it interesting when the author of this article said that there is no race, but rather that there are only geographical gradients, and that there is no sharp difference between people of different regions or continents. This makes me wonder how the world would act today if everyone looked at it with this sort of scientific view. Would there have ever been slavery?

            The biggest controversy brought to light in this article is whether humans came strictly out of Africa, as the Out-of-Africa theory would suggest, or if they came out of Africa, Europe, and Asia, as argued by the Multiregional theory.  So far, almost all of the evidence points toward the Out-of-Africa theory. Another popular controversy brought to light in this article is the argument over whether humans interbreed with archaic species, such as Homo erectus. There has not been any solid evidence to prove that interbreeding occurred yet, however the fact that modern humans have a deep ancestry would support this possibility.

            This article left me with many different questions to ponder. One of the most interesting questions that I would like to find out is whether we will one day be able to find suspects in criminal cases through examining lineages. Particularly, lineages that are connected by a common surname. I would also like to know what impact genetic diversity plays in our ability to survive?  Some more general questions that I would like to find the answer to would be why the Africans left in the first place. Was it because of a change in climate, or was it because of a loss in food? Was there another reason? My last question that builds off of the article is whether the rate of evolution is still accelerating to this day? Could our improvements in medicine, which seem to eliminate natural selection and survival of the fittest, be causing the rate of human evolution to decrease?