Not too long ago, I wrote a summary of the DNA/Book of Mormon issue which I hope was understandable to even those who know very little about DNA. My own experience with reading the DNA articles is that they are difficult to understand, so I tried to break down in common, understandable terms, with as little jargon as possible. One of the things I pointed out there is that people have ancestors whose DNA is undetectable. The notorious Greg Smith has recently brought a case in point to my attention.
Ancestry.com genetics expert Anne Gillespie Mitchell fielded a question from a lady whose great-great-grandmother was 1/4th Cherokee. Yet when her DNA was professionally analyzed, “the results did not show any evidence of [her] Cherokee connection.” Anne explains that since it would be her 4th great-grandparent who was a full blooded Cherokee (that is only 6 generations back, not counting the questioner; which, for my genealogy anyway, takes me back to about the mid-18th century—not a super long time ago), the questioner probably only has around 1.5625% Cherokee DNA, “And that may not be enough to detect Native American ethnicity.”
Now let’s think about this for just a minute. If an ancestor from probably around the early-to-mid-18th century (maybe back into the late-17th century, depending on how much older this lady is than me) can be undetectable by DNA, what about an ancestor from 600 BC? Just something to think about, I suppose.