Human (and other) cells contain 'mitochondria' (mt), whose main function is to produce the energy required by the cells. Mitochondria contain peculiar genes, whose function is create the proteins, mainly enzymes, required for the obtention of energy derived from glucose. Many women have been tested all over the world and found to have exactly the same mitochondrial genes ('mtDNA').
Since the DNA of the mitochondrial genes is inherited from the mother, it is clear that all women at present are descendants of ONE specific woman. Being known that DNA mutations occur every 100,000 to 200,000 years, it is accepted that all women --therefore all of Mankind-- are descendants of a woman who lived not more than 200,000 years ago. She has, therefore, been assigned the very appropriate moniker "the mtEve."
Problem is, what happened to the other women? Why did only one woman leave descendants? This conundrum is referred to as the "bottleneck," which let pass only the mtEve's descendants. For the sake of clarity, let's assume that the legend of the Universal Flood is based on real happenings, and that only one woman on board Noah's ark succeeded in conceiving children, male and female. By dint of inbreeding, only her mtDNA was passed on. This woman would then be the mtEve, the bottleneck having been the rather drastic theogenic hydrotherapy. This scenario could be examined seriously only by creationists, though.

I have written an essay, mostly fantasy, examining the subject from different points of view. I hope that at least one person will enjoy reading it as much as I did writing it. The intention is basically to contribute to the thinking process, the central purpose of this Internet site. On the subject of the mtEve, I believe that archetypal insights, bolstered by certain myths, may give rise to a theory which purports to clarify the matter.

Firstly, we should contemplate the following possibility: The biblical Eve was a woman who consorted with a man, a provider, impersonated as "God." As he was away, hunting and gathering, she stayed at home with their adolescent SON, Adam. Incest, then prevalent, was eventually proscribed as inimical to society. The myth of Paradise reflects this transcendental occurrence, as follows.
Upon his return at the end of his hunting and gathering chores, the provider found his consort --'Eve'-- cavorting with their son --Adam. Angrily, he expelled Eve together with Adam from his well-provided home (a "Paradise"). Sometime later Eve returned, minus Adam, and was forgiven; she alleged that God had appeared to her in a dream, promising to father her a son {"I got myself a man with God"}. Cain, the paradigmatic bastard, was born. He was not well liked by his putative father, who obviously preferred his son, the young Abel. (Abel was the provider's second son, while Cain was his first grandson. Cain, induced by this undisguised and unfathomed preference, murdered Abel, his half-brother from mother.
Although again I am dealing with a creationist story, my new twist of it is perfectly realistic, and actually derived from my analytic reading of the Bible's relate. Let's leave Cain for a moment...

Next, we have to consider the following other scenario: According to the Bible, "Man" was originally made "both male and female" (androgynous). If we theorize that originally all animals were androgynes, it is possible to envision a peculiar cosmic phenomenon at a given time, which produced a mutation affecting one of the two germline genes of some early embryos, among them a human one. As a result, not only the feminine traits of this embryo became less apparent, but the masculine ones expanded by virtue of the molecular changes in the damaged germline gene, which now became "male," as opposed to the "androgynous" gene. That other genes --non-germline-- were knocked-out from the affected X chromosome, giving thus rise to future hemophilia and other unrelated 'sex-linked' diseases, just goes to show that there was no teleological determinant for such mutation.
Now, this fetus, "ADAM" --the first X/Y creature-- was bigger than the androgynes, thus causing suffering at delivery, giving rise to the archetypal-mythological expression of delivering sons with pain. His mother, "EVE", had to hide from her consort, who did not like the little monster. As Adam grew to maturity, he and his mother begot "CAIN," who had inherited from Eve the same mtDNA that Adam had previously inherited from her. Cain was regaled with several brothers (men) and "sisters" (androgynes), born to Adam and Eve after himself. In this closed society, Cain hated those who didn't resemble him, on account of being endowed with Eve's other X chromosome --and therefore a different mtDNA. Cain systematically murdered these siblings, so that eventually one single type of mtDNA remained. These males were not only giants, they were aggressive. By mutation, they had become not only sexually distinct, but also carnivorous, adept at swinging an antelope's femur to bash the crania of edible baboons. {"There were giants at that time and they populated the earth"}.

Eve's powerful progeny, suitable selected by Cain, multiplied and eventually exterminated the weak surrounding androgynous populations, leaving to posterity the exclusive mtDNA of "Eve" in all human cells --thus explaining the "bottleneck."
By the way, the androgynes underwent 'androgenic' evolution: Those with predominantly male characteristics were rejected as mates, or else died when delivering a son, on account of their narrow pelvises. Woman is basically complete and consequently emotionally independent of the male, while the latter is defective, incomplete, looking for females to 'complement' the deleted counterpart.

If this "Cain's theory" is true, then the mutagenic conversion of one of our androgynous ancestors into our ancestral father ("ADAM") and the subsequent forced selection of our ancestral mother's mtDNA ("mtEve") by "CAIN," happened some 200,000 years ago, when "Paradise" was truly lost, if being androgynous, gentle, and herbivorous, embodies the picture of happiness.