Sorry, I was unclear. What I meant is: if a female has a Jewish female ancestor as part of the female only lineage from which they get their mitochondria, then they definitionally have an “unbroken Jewish maternal lineage”, because it could be no other way. But it’s not really an interesting observation, since it’s true of most Jewish women that this line reaches extremely far back in time (since Jews generally don’t seek converts and, so, being Jewish is mostly a genetic matter, in practice).