Scientific Inquiry: Mitochondrial Eve

Today it is almost common knowledge that a child receives half of its DNA from its mother and half from its father. A lesser known type of DNA is Mitochondrial DNA which is unique from the type of DNA which gets passed down from a child's mother and father. This type of DNA is passed down 100% from the child's mother. So while 50% of a child's DNA comes from its mother and 50% from its father, if you look back at the family line, only 25% of that comes from the child's grandparents. Soon those numbers become very small, almost obsolete, so that very quickly, the child's DNA no longer looks like that of its far placed relatives. In contrast, because Mitochondrial DNA is passed down in its full form from mother to child, it can be traced much further back down genetic lines. This has led scientists to come up with the concept of Mitochondrial Eve, an ancestral mother stemming from Mitochondrial DNA.

Mitochondrial Eve is thought to be around 200,000 years old and to have originated from somewhere in Africa, most likely Ethiopia. The interesting part about Mitochondrial Eve is not necessarily that she could have existed, but all of the changes which the DNA has undergone despite potentially originating in the same person.

The theory of why all of humanity is so unique despite the concept of a common ancestor begins with the movement from Africa to the far reaches of the world.

As this happened, it became necessary for humans to adapt to their new surroundings. This did not happen quickly, but over generations, Africans who needed dark skin in order to combat constant sun exposure began to lose some of their color because they were no longer bombarded by the sun in their new environment. Peoples who were genetically predisposed towards thinness began to hold on to body fat more easily in order to fight back against their new cold climates. Slowly, the many different people of the world came into being just because they needed to change their appearance in order to adapt to their environment. Once melanin production was no longer the most important aspect of keeping someone alive, in say, Europe where there is not as much sun, melanin production slows down significantly and the body can use that energy in a more productive way.

In this way, although Mitochondrial DNA might be able to be traced back to one ancestor, there are huge variations in the looks of people throughout the world. Just because people look different does not mean that they do not have a connection to this ancestral mother, it only shows the power of gene mutation in order to maintain a more effective body.