The original African mbira?

It may be possible to show, one day, that all the different mbiras of Africa are descended from one another, and that all stem from one particular type, which can then be assumed to be the form of the instrument as it was originally invented. I would like to present here some evidence to show that in one large part of Africa at least all the many types of mbiras can be traced back, with greater or lesser degrees of probability, to one type which must, at least, be very ancient, and at most, if connections with, or distribution to other mbira areas of Africa can be proved, may be the nearest we will get to knowing the earliest form of the mbira in Africa