Question on mtDNA "eve"

I've read a little on the mtDNA "eve" and I don't quite understand. It is defined as the most recent female from whom all living humans are descended through purely female lines. So are all modern day humans descendents of this one single female some 200,000 yrs ago or are we descendents of single population of ancient humans that had its roots in Africa with a single branch leading out of the continent. Also, is there an estimate on the size of this branch that survived and left Africa?

Spoke to soon. I found at site at talkorigins which explains it well.What, if anything, is a Mitochondrial Eve?

There is some evidence that mtDNA can also
come from the father. Not sure how that impacts the
discussion on ME though.

Peter,I am very interested in the evidence that says mtDNA can also be inherited paternally. Do you have any references I could look up to learn more about that?-Alec

I read about it in New Scientist, and I don't have a copy to hand
but some URL's of relevance are::http://news.bbc.co.uk/1/hi/sci/tech/294808.stm
SREL Home page, Office of Research, University of Georgia
http://www.imbc.gr/biblio_serv/imbccr/X0029_1.34.html
Welcome | Department of Cell and Developmental Biology | The School of Molecular and Cellular Biology | University of Illinois Urbana-Champaign (NOTE:: PDF file)
DNA by Dr KnightI'll let you critique the sources for yourself, and you can also
try a web search using::"paternal mtDNA"(NOTE:: include the double quotes for an exact phrase match).

Peter,Thank you. I've done some searching myself, and found a few journal articles.-Alec