‘Mitochondrial Eve’: Mother of all humans lived 200,000 years ago
ScienceDaily (2010-08-17) — The most robust statistical examination to date of our species’ genetic links to “mitochondrial Eve” — the maternal ancestor of all living humans — confirms that she lived about 200,000 years ago. The study was based on a side-by-side comparison of 10 human genetic models that each aim to determine when Eve lived using a very different set of assumptions about the way humans migrated, expanded and spread across Earth.
The SCIENTIFIC process, that ivory tower which our civilization (Western) holds in high esteem, relies heavily on modeling. So? Well…’Modeling’ requires a lot of something we don’t often ascribe to the eggheaded nearsighted concept of a scientist we grew up nurturing. Modeling is an art, requiring lots of imagination and creativity.
It’s a talent we all possess and so it’s responsible for continuously molding us as a species, and not to be understated. From a species of hunter gatherers to the sprawling agrarian and urban dwellers we are today, it’s the human mind and its ability to create possibilities other than we have before us which helps define us. Look around you, you’ll realize that everything you see, touch, or hear right now, is there right now because it was first in someones mind and subsequently manifested. Our urban centers are the supreme expression of creativity in my point of view. An immersive reality of our own construction, seemingly set apart from nature, yet supported by it just the same. It’s that very capacity to create which keeps the coals burning in the ivory tower. Raw unbridled imagination. Interestingly, to me, this imagination extends not only forward into our future, but it also reaches far back into the past. It’s perhaps one of the most important tools we have in the quest trying to answer the question of where we come from. Cosmology, that branch of Science/Philosophy which deals with the study of origins, also relies on creativity and imagination. I should stop here and point out that science, and cosmology–which every culture on Earth knows something about, but by a different name, be it Islam, Judaism, Christianity, Hinduism, Animism- all have something very interesting in common, and you’ll recognize the theme if you’ve been paying attn. They’re all expressions of human creativity and the diversity therein. They answer that haunting question of who and what we are, and try to give us perspective, thereby removing existential anxiety from our minds, that we can go on about our lives. COSMOLOGY, as the ‘ology’ is a little different than what came before in that it tries to reconcile its model of origins with objectively testable and verified statements. In steps the institution we know as SCIENCE.
As I started with in the beginning of the blog, Science relies heavily on models, which rely on assumptions, those statements and suppositions which we MUST begin with as the foundation of our models. The study I cite here engages on the testing of various models of human migration and population size as they relate to the genetic evolution of mitochondrial DNA. A short list of simple assumptions or premises which are key to understanding or refuting the claims of this study :
1. DNA is the heritable element of biological organisms, it passes down conserved from parent to offspring.
2. DNA is the heritable element responsible for parent/offspring likeness, but it also mutates, and at a predictable rate across generations.
3. Mitochondrial DNA allows you to trace maternal lineages and therefore migrations across time.
3a. Mitochondrial DNA mutations occur at a calculable rate and can in essence be used as a clock. The more mutations occurring in a mitochondrial gene then, the more divisions, therefore persons, therefore generations or time span is assumed to have passed between the originally sequenced Mt DNA and the newly investigated sample.
Let me unpack that, The more differences that are seen upon genetic comparison (DNA base pair comparison of genes Mitochondria have, 37) of Mitochondrial DNA from fossil bone and a currently living human,or of another fossil bone (of similar or different geologic age) the more distant the relationship between the individuals is implied. And that relationship can be expressed by a number of years between them.
So science being the self correcting institution it is, people often try to improve upon previously established models. Regularly adding in corrections for factors that the prevailing model left out- but which may be important for accuracy of the output. This study compared the output of 10 different ‘genetic similarity’ or molecular clocks, each which aim to accurately gauge the amount of time that has passed between two samples of mt DNA of different geologic ages. The result, a confirmation that the differences between the 10 models are miniscule and that they’ve pretty much come up with the same number-200,000 years between humans living today and the oldest sample of mitochondrial DNA believed to come from a human progenitor, hence the nom, Mitochondrial Eve.
Here is an example of research which, for ideological or faith based reasons may be hard for some to swallow. But it is also the perfect example of research, the methodology, and of the assumptions which scientists base their conclusions on, however grandiose they may seem. So long as you understand the causal chain of ideas, and can exercise reason you too can understand, and even intelligibly refute how it is scientists arrive at those grandiose claims, which sometimes can stand at odds with religious propositions.
Understanding is the first step to neighborly tolerance, and it should be required of all of us even when we challenge prevailing religious or scientific notions.
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