In genealogy, there's a relatively unusual approach that consists of only taking into account your female ancestors. So, you disregard your father entirely and look only at your mother. Likewise, you disregard your maternal grandfather, and look only at your mother's mother. And so on. The set of ancestors that you obtain in this way describes your so-called uterine ancestry. In many ways, it's a sound approach to genealogy. In concerning yourself constantly and exclusively with the unique womb in which each female ancestor developed, you remain on relatively firm ground. After all, an error at a maternal level is less likely, for obvious reasons, than ambiguities or downright lies concerning the identity of somebody's father. Besides, the concept of matrilineality (as it is called in genealogical terminology) corresponds to our intuitive impression of having once emerged from the body of our mother. To put it in silly terms, most humans surely feel more like a well-hatched egg than a grown-up sperm, even though we've learned that we're a little bit of both.
The only problem about family-history research of a strictly uterine orientation is that, in societies where a married woman takes the surname of her husband, the researcher is likely to run out of data rather rapidly, at least much earlier than in investigations in which both male and female ancestors are being researched. In the case of my personal research, the disparity between a purely patrilineal and a purely matrilineal approach is flagrant. Concerning possible ancestors called Skyvington—or a variant of this patronymic such as Skivington, Skevington, Skiffington, Skeffington, etc—I've already filled a small book with research results. [Click here to visit this website.] But, when I concentrate solely on my uterine line, I find my maternal grandmother Mary Jane Kennedy [1888-1966], my Irish-born maternal great-grandmother Mary Eliza Cranston [1858-1926], my maternal great-great-grandmother Eliza Dancey [1821-1904], and then I run into an ancestor named Mary Adams about whom I know nothing whatsoever. And there's little chance of my ever learning the name of this Mary's mother. So, I've run up against a genealogical brick wall after four or five matrilineal generations.
Now, the uterine approach to genealogy has some strange but positive consequences when we look at things from a genetic viewpoint... which is, after all, a perfectly normal way in which to deal with family history. Every human baby inherits from its mother a stock of weird stuff, stored in every one of our cells, called mitochondria (in fact, a form of DNA), which can be thought of as tiny energy suppliers. Were it not for our mother's gift of mitochondria, our cells would be like factories without fuel, or cities without electricity. We would instantly collapse and die. Human males, like females, need mitochondria to survive. But a father, unlike a mother, does not transmit any of his stuff to his children. And, because mitochondrial DNA is only transmitted down uterine lines, this means that it can be used as a "marker" (that's not quite the right term) in the genealogical domain. By analyzing the mitochondria of two individuals, it's possible to ascertain whether they have a common uterine ancestor.
In the context of the famous tomb at Talpiot, this was the kind of analysis that enabled geneticists to declare that the individuals designated as Jesus and Mariamne (allegedly Mary of Magdala) were not related in a matrilineal sense. And this conclusion made it feasible to imagine this couple as man and wife.
In fact, the existence of mitochondria makes it possible to hypothesize the existence of common female ancestors—vastly more ancient than Biblical women—for all human beings living today. Genetic genealogists use a rather unromantic name to refer to the most recent female in this role: Mitochondrial Eve. She wasn't exactly a plump white-skinned European beauty. Mitochondrial Eve lived in Africa some 150 thousand years ago. Whatever she looked like, she's the lady to whom we can say thanks for passing on to us the primordial cell energy enabling humans to crawl out of their beds every morning, to make hay while the sun shines... before getting back into their beds of an evening, maybe to make more mitochondria.