Conservation Biology

Monday, July 24, 2006

REAL EVE – REVIEW

This documentary focuses on genetic lineages traced back through the analyses of mitochondrial DNA. Mitochondrial DNA is passed on by the mother to all her descendants, as it is only the egg cell (not sperm cells) that contains mitochondria. This explains the reference to Eve, the proverbial mother of all people. DNA undergoes random mutations at a certain rate and by analyzing the DNA from distinct populations around the world, one can establish the age of “tribes” and how they relate to each other. It is through this technology that the “Out of Africa” hypothesis has now been widely accepted by scientists.

The documentary tells the story of how humankind can be traced back to a single lineage that originated in Africa, here called the “Real Eve”. The spread of humankind and their subsequent population of the whole world is graphically demonstrated by reconstructed scenes from long ago and narrated by (a rather monotonous sounding) Danny Glover. Leading scientists explain how the evidence found through this mitochondrial DNA analyses links with archaeological finds along the route.

I found the documentary binding, but was put off by the lengthy and over dramatized graphic reconstructions. (I guess this is what keeps the kids glued to the screen!) Also, as this is a hypothesis it should be stated and not sold as the absolute truth. Recent evidence does support this theory, but exactly when, how and which route was taken by the first humans to populate the world remains hypothetical. The fact that the absolute truth is still out there, is demonstrated by the different time scales and routes suggested by an analysis of Y (paternal) chromosomal DNA, compared to mitochondrial (maternal) DNA.

None the less, the documentary remains educational and fascinating, and as with The Journey of Man, it emphasizes the interconnectedness of all people. Hopefully this knowledge will ultimately create more tolerance and understanding amongst the different nations and races.


Karen Marais
BCB Hons NISL student
University of the Western Cape
Private Bag X17
Bellville

E-mail 2657211@uwc.ac.za

Web http://brit-journal.com/karen2006bcbnisl/

JOURNEY OF MAN - REVIEW

Journey of Man is a National Geographic documentary about the Y chromosomal lineage of human kind. The documentary presents a hypothesis, based on an analysis of the Y chromosome found in men, which trace man’s journey out of Africa.

The sex chromosomes do not get chopped up and reshuffled as the other chromosomes do during sexual reproduction. That means that a father will pass on an exact replica of his Y chromosome to his son. Sometimes a mutation occurs during replication and this mutation is then passed on to all male descendants. These tell-tale mutations are used as markers by geneticists to trace back specific lineages. Documenting specific markers allowed them to reconstruct the most likely routes taken by our ancestors to populate the globe. Dr. Spencer Wells is a geneticist, who was part of a team of scientists that analyzed the Y-chromosome, of isolated populations. In this documentary Spencer Wells takes the viewer on a scientific tour of the routes and extraordinary detours he believes humankind took during this epic journey.

According to Wells, it all started some 50 000 – 60 000 years ago in Africa. The most ancient Y chromosome marker was found in the San people of Botswana. Thus, it is here where his journey begins. The next stop in this incredible journey is Australia, as a marker found in the south of India links the Australian Aborigines to Africa. The journey continues to south-east and then to central Asia. It is here that a marker was found that links almost all Europeans, Asians and Native Americans, hence Spencer Wells refers to central Asia as the “nursery of humankind”. In Siberia he meets up with nomadic reindeer herders; around 13 000 years ago a group of their forefathers crossed into the Americas, populating the New World.

The journey portrayed by Spencer Wells seems incredible; at times almost impossible, taking the harsh conditions and stumbling blocks into account. The story is well narrated with a good mix of scenery, interesting history, real people and hard science. The hypothesis is collaborated by experts from different fields, offering explanations of why certain routes were taken and of specific physical adaptations that occurred under certain conditions. The viewer also gets a glimpse of some of the descendants along the routes followed by mankind. There is currently little archaeological evidence to support this hypothesis, but changes in global climatic conditions do fit with the explanations provided.

I did find Spencer Wells’s approach at times somewhat insensitive, offering his scientific theory to people who had not asked for it. Sensing the animosity from an Australian Aborigine and later also from Navaho Indians, he explained that this is a European way of looking at the world by stating: “my bias as a scientist is I want to see evidence”. But does this make it ethical to offer information that may be disturbing to people with their own rich cultures and beliefs if they had not asked for it?

Overall, I found the documentary fascinating, but it would have been even better without the focus on a “scientist hero trying to enlighten the world” theme to it. I also do not agree with the way everything was portrayed as the absolute truth, while ultimately it remains only a hypothesis. The two things that struck me most was; 1) the statement that modern man’s curiosity and his ability to imagine something beyond what he can see, along with incredible adaptability and endurance, took humankind to all corners of the world, and 2) the fact that the available scientific evidence illustrates how closely we are all linked together, which should ultimately serve to unite us.


Karen Marais
BCB Hons NISL student
University of the Western Cape
Private Bag X17
Bellville

E-mail 2657211@uwc.ac.za

Web http://brit-journal.com/karen2006bcbnisl/