Ok, next I would appreciate it if you gave a clear and simple explanation of how they calculate this. Please answer these questions: how did they get the 2000-5000 people and the number of years ago? What do the calculations look like? What data are they looking at to do these calculations? How does this data actually work? I would like you to be specific and to do the explaining on your own without telling me to read an article.
I carry out experiments daily at my job and understand how the different variables must be controlled and how details can be presented to support the view you want. I would like an outline of the exact method/procedure they use to get these numbers. This looks like a very interesting and convincing piece of evidence but I will not be happy until I can scrutinize every tiny detail of the procedure. You don't have to type this part out, just give me a link going directly to the procedure so I can find exactly what I am looking for.
Since I am at a co-op college I am currently on work rotation and I cannot contact my teachers, but I will be certain to get more information from them once I start up classes again.
It's not a single method or procedure. There are literally dozens of approaches with thousands of papers on the subject. Often mitochondrial DNA is used because this is the easiest kind to extract from bones and stays preserved over long timeframes quite well. There are thousands more peer reviewed papers explaining the processes and procedures used to extract and replicate this DNA without contamination ( such as
http://www.jstor.org/discover/10.2307/7 ... 3452267047 )
Often these studies use various mutation models, the royal Society paper used 783 micro satellite (short repeating chains) from 53 existing populations and analyzed them using 5 different mutation models. The data itself came from another source (
http://www.cell.com/AJHG/retrieve/pii/S0002929707639901). Basically they looked at mutation rates such as increases or decreases in the repetitions and whose rate can be measured given we have access to many generations of human DNA.
The Oxford journal article use mitricondrial DNA studies and combined it with arechological evidence to form thier results. They did this because of how well it is preserved and extracted from bone remains. They also used growth modeling based on mutation. It's is quite complicated when tryin to determine a possible size and scope of a bottleneck 2M years ago in human ancestors.
In short it would take many many pages to explain the methods and hundreds to show procedures and many thousands to show the data. If we all came from 2 people 6 thousand years ago (or any timeframe) it is quite easy to show there is no possible way to explain the variation we see in both living samples, as well as recently exhumed, as well as the arechogical samples. I won't even bring up that we have human DNA samples far older than 6k years.
The short two sentance answer is : You can find people that do not share common ancestry (have a high amount of genetic difference) since they came from different portions of this early breeding population. This wouldn't be possible if everyone came from two people and doubly so if this was a mere 6,000 years ago.
Since you attend college - tuition often grants you access to journals that are behind pay walls. If you are interested you should be able to look at far more than I can as I do not have multiple (or any) journal subscriptions that publish these papers.