You have a valid point about that large range, and IMHO its good to see that scientists are being kept on their toes so to speak. I probably wasn't clear enough, but what I was saying was that those different methods of clocking the rate were generally more supportive of a date that was older than the one date expected from creation-science advocates.
It should be remembered that every date calculated based primarily on the assumption of human-chimpanzee common ancestry (there are many) is not an independent method of clocking the rate, thus the many dates (ie: 171, 000, 200,000, 844,000, etc.) calculated based on this assumption are not independant witnesses supporting the current evolutionary scheme , in fact they are not even one witness supporting evolution (as they are calculated primarily based on it to begin with), but instead provide a baseline spread to potentially test the current evolution scenario by other means. Furthermore, given that the selected radiometric dates for the fossils used to calibrate the human-chimp split will almost certainly be in the "millions of years" range due to uniformitarian assumptions, all of these various starting dates will automatically be much "older" than the Bibilacal eve date.
Pedigree dates "older" the Biblical timeline can probably be relatively easily accounted for be assuming a possible higher mtDNA mutation rate in the past. Woodmorappe discusses this in his book Noah's Ark a Feasibility Study.
Even if they all didn't point to one date in particular. How trustworthy is the clock then though?
Given that mtDNA may easily be capable of different speeds of rapid mutation, clock calculations may be difficult to accurately assertain, however Biblical creationists expect a generally rapid rate.
Well it could very mean that the assumption of a linear and constant rate of mutation is wrong. Maybe the rates vary in time as well as between some pedigrees.
I agree that this could easily be so, this is why evidence such as Neanderthal divergence is not necessarily very good evidence against a Biblical eve date.
Again, the whole idea of a constant molecular clock may not be feasible. (Thats where the calibration with the fossil record and its dating comes into the picture)
The mution rates (and corresponding mt Eve dates) generated using the fossil record (with a subjective interpretation of fossils*) all assume a uniform rate of evolution (as well as of course evolution) to begin with.
*As an example of this (I believe that the following is correct, though I need to check) is that the Sivapithecus fossil/fossils were once thought to be an "ape-man" on this side of the human chimp split. Since Sivapithecus is "dated" at around 15 million years old it was used to calibrate the human-chimp split at over 15 million years ago. However, then problems developed with this date of the split and evolutionary based dates compared with other apes. Furthermore more studies revealed that Sivapithecus was essentially similar to an orangutan, so then evolutionists used Sivapithecus to date the orangutan split ! The same fossil was used first for the human-chimpanzee split and then later for the alledged much older orangutan split. Then based on the Sivapithecus orangutan split date they calibrated the human-chimp date at around 5 million years ago. This shows just how subjective evolutionary fossil evidence can be.
