Comment: I ask my biological questions from the point of view of mathematical proportions. I am not a biologist.
Are there significant differences in DNA from Egyptian Mummies vs. those available from humans today (5K years aprox)?
Related to this question, I found this answer https://biology.stackexchange.com/a/20301/13003, but just because of lactase tolerance it takes around 7K years!!! which for me is very slow! (without taking into consideration that tolerance probably is only adaptation or this change is detectable at DNA level?)
To get back to Homo Sapiens (300K years) we would have to revert in 60 (300K/5K) similar time ratios.
I found this question Are there differences in DNA between humans of today and humans from 2000 years ago?
Obviously the changes are not homogeneous, perhaps some occurred faster than others, however, the fact that such changes have not been detected in 5K years exerts pressure for the changes to occur almost immediately; that is to say, the Homo Sapiens species appears and immediately there must be changes at the DNA level.
Not only the immediacy of the change, but also the amount of accumulated changes between Homo Sapiens and modern man (ie, simultaneous DNA changes between a subject and his great-great-grandparents). If changes in climate, environment and food are determining factors, it implies an instability of the DNA (few generations to present a change).
Personally, the fact that no change in DNA has been found for at least 5K years casts doubt on whether we came from Homo Sapiens.
Same calculation could be derived from Homo Sapiens. 66M years after the destruction of the meteorite. 300K years for changes in the DNA of Homo Sapiens and the Human of Today. That produces 220 time ratios (66M/300K).
Comment: I personally think we would need more time ratios to get from a species after the destruction of the Meteorite to Homo Sapiens 300K years ago
What other considerations should I take into account for a more biologically appropriate analysis?