“The human understanding when it has once adopted an opinion ... draws all things else to support and agree with it, and though there be a greater number and weight of instances to be found on the other side, yet these it either neglects or else despises or else by some distinction sets aside and rejects.”
Human mitochondrial DNA (mtDNA) is conventionally thought to be inherited only from the mother. Generally, this may be true although several recent papers “have suggested that elements of mtDNA may sometimes be inherited from the father.”  Nuclear DNA comes partly from each parent. If mtDNA comes only from the mother, then the mother’s mtDNA had to come only from her mother who got it from her mother, etc. back to the original mother.
Starting from the original mother, that mother may have had only one or maybe many daughters with each daughter potentially starting a new branch in the family tree. Then daughters from each of these daughters starting new branches, etc. Potentially any of the branches may die off if for instance a daughter has only sons, deaths due to plagues, wars, or natural disasters, etc. “In human genetics, the Mitochondrial Eve ... is the matrilineal most recent common ancestor (MRCA) of all living humans.”  Hypothetically, Mitochondrial Eve:
1. May not be the first woman
2. May be more than one woman living at the same time
3. May be a different woman from time to time
4. May not be the most recent ancestor of all human beings today
Not one of the above hypotheticals rules out the Eve of the Bible as the first woman although she may not be the MRCA.
DNA is highly subject to mutations that are constantly being repaired by enzymes, but they too make errors albeit rarely. Over time errors that are non-critical to survival can build up in one population group that are different than those in another. Various studies have identified many of these differences on a worldwide basis. Anthropologists and paleontologists have used modern mtDNA differences between population groups to try to identify migration patterns and determine where humans came from.
One once popular hypothesis for human origins is known as Out of Africa where all mankind supposedly dispersed from Africa.  This hypothesis was based on empirical evidence indicating that Sub-Saharan African tribal groups have a higher amount of mtDNA variations than other Africans and non-Africans. This empirical evidence was then interpreted on the assumption that the variations result from mutations that increase in number at a constant rate over time. So, if the number of mutations increase at a constant rate over time, those Sub-Saharan African populations with more mtDNA mutations must be older than other African and non-African populations with less. So, then if the Sub-Saharan African populations are older, it could be further assumed that the younger populations must have dispersed from them and migrated originally out of Africa.
There are several weaknesses with the Out of Africa hypothesis some of which are as follows:
1. The time from the first common mother to the present for each population group alive today is the same. So, differences in the amount mtDNA mutations observed in different population groups today must result from something other than time.
2. The more generations there are the higher the probability of more mutations. For example, culturally one group’s mothers have babies beginning at about age 15 years old and another beginning at about 30 years old. Theoretically, the first group over time could have had approximately two times the number of generations than the second group.
3. Certain mutations in the mtDNA control region may be slightly beneficial under certain environmental conditions and become predominant by design or natural selection.
4. The repair mechanism in the Sub-Saharan African population may make slightly more errors than that in the other African and non-African populations.
5. The rate of DNA copying errors may be higher in the Sub-Saharan African population.
6. In smaller population groups, mutations build up faster.   The Sub-Saharan African population may have been limited to small tribal groups, while the other populations may have expanded during the same period to much larger populations.
Today, unequivocal evidence supporting the Out of Africa hypothesis is not there. The biblical account that places the dispersion of population groups from the Middle East has not been disproven.
When did Mitochondrial Eve live? To answer this, a clock is necessary, and some evolutionary researchers think that the mutations in the mtDNA might provide a molecular clock. Six of the major assumptions by these researchers in the mtDNA clock are:
1. The mutation rate of mtDNA has been constant. 
2. The first woman came from a common ancestor with the Great Apes (e.g., chimpanzees). 
3. Based on paleontology which has its own plethora of assumptions, the diversion between the Great Apes and humans occurred about 3 to 6 million years ago.  
4. The mutation rate is the same for humans as apes.
5. Differences in mtDNA between apes and humans result from mutations. 
In the late 1970s to early 1980s, a team of evolutionary researchers using these and other unproveable assumptions estimated the human mtDNA mutation rate at “0.02 substitution per base (1%) in a million years.”  Other human mtDNA mutation rates based on similar evolutionary assumptions have been published ranging from 0.025 to 0.26 substitution per base in a million years.  Using the latter ranges, places Mitochondrial Eve living somewhere approximately 60,000 to 630,000 years ago. 
Mutation rate estimates were calculated by counting the differences between the mtDNA for the ape the researcher group believed to have shared a common ancestor with the first human and human mtDNA today. The total count of these differences was then divided by the date the researchers believed the split (divergence) occurred based on the fossil record resulting in an estimated substitution rate per base per million years. “The most widely used mutation rate for noncoding human mtDNA” takes this date to be “5 million years ago.”  It should be reemphasized at this point that the researchers are not actually counting differences due to mutations but assumed mutations.  Such an approach is highly biased by the evolutionary presumptions of the researchers. It is no wonder that the researchers came up with results that appeared to validate each other.
What are the real mutation rates? This is a difficult problem because “individual DNA residues are chemically altered over time” , and no one was sampling it while it was mutating.
Around 1979, one research team decided to directly measure “the intergenerational substitution rate in the human” mtDNA control region (CR). They “compared DNA sequences of two CR hypervariable segments from close maternal relatives, from 134 independent mtDNA lineages spanning 327 generational events.” The empirical results were 2.5 substitutions per base per million years which they indicated is roughly 20 times higher than “estimates derived by phylogenetic analyses.”  In biology, phylogeny is an evolutionary tree.
A study published in 2008 “calculated the consensus sequence for human mitochondrial DNA using over 800” publicly “available sequences. Analysis of this consensus reveals an unexpected lack of diversity within the human mtDNA worldwide. Not only is more than 83% of the mitochondrial genome invariant, but in over 99% of the variable positions, the majority allele was found in at least 90% of the individuals.”  The study authors claim for several reasons that the consensus sequence is “nearly identical to the real Eve mitochondrial sequence.”  Also, they state, “the lack of significant worldwide variation indicates a young mitochondrial genome.” 
Theories premised on evolutionary assumptions provide no tangible proofs of when the most recent common mitochondrial Eve lived nor when the various population groups diverged. The biblical account for Adam and Eve dates her from about 6,000 to 6,500 years ago by linked genealogical dates that tie into known dates of certain historical events. Also, the biblical dispersion of the population from Babel in the Middle East is also dated by the same means. Empirical results in the last two paragraphs above agree with the biblical account. However, “no calculated date (even one that supports a biblical conclusion) is free of non-verifiable assumptions and hence cannot be used to ‘prove’ the Bible.” 
(a) Wer-Al Zwowe, Public domain, via Wikimedia Commons
 Harrub, B., Thompson, B., The Demise of Mitochondrial Eve, Apologetics Press, Inc., 2003
 Mitochondrial Eve, Wikipedia, viewed internet October 2022
 Carter, R., The Neandertal mitochondrial genome does not support evolution, Journal of Creation 23(1) 2009
 Carter, R.; Criswell, D.; Stanford, J., The “Eve” Mitochondrial Consensus Sequence, The Proceedings of the International Conference on Creationism, Vol. 6, Article 12, (2008), 112
 Carter, R., The Neutral Model of evolution and recent African origins, Journal of Creation 23(1) 2009
 Thomas, B., Evolutionary Dogma, Not Science, Kicks Out Adam, Institute of Creation Research, 2014
 Carter, Ref. 6
 Carter, Ref. 4
 Wieland, C., Mitochondrial Eve and biblical Eve are looking good: criticism of young age is premature, Creation.com, 2006
 Mitochondrial Eve, Wikipedia
 Loewe, L.; Scherer, S., Mitochondrial Eve: the plot thickens, Trends in Ecology & Evolution, 1997
 Carter, Ref. 6
 Gibbons, A., Calibrating the Mitochondrial Clock, Science 279: 28-29, American Association for the Advancement of Science, 1998
 Carter, Ref. 4
 Parsons, T.J., et al., A high observed substitution rate in the human mitochondrial DNA control region, Net. Genet. 1997 Apr; 15(4):363-8
 Carter, Criswell, Stanford, 111
 Carter, Criswell, Stanford, 114