A reader has been so kind to send me a copy of this Chinese paper, which I have hanged at ZohoViewer:
Chen Zhiyong, Migration and Diversification of Mitochondrial Haplogroup N in EastAsians. Communication on Contemporary Anthropology 2009.
The paper is in Chinese (and can't find any English version) but has loads of nice and informative graphs and maps with legend in both languages about macro-haplogroup N and some of its derivatives, specially A and N9 (incl. Y).
As the saying goes: an image is worth more than a thousand words... specially if these are in a language you can't understand. Still, if any of you can read some Chinese and give some feedback, I'm of course interested.
Most importantly the paper seems to confirm a SE Asian origin for macro-haplogroup N. Specifically it suggests a SE Asia as probable origin:
Fig.2 A simplified Median-joining Network of haplogroup N based on mitochondrial HVS-1 Keys for the colors: Red for the Tonkin Bay area, Green for South China, Orange for North China, and Blue for Southeast Asia.
Another relevant finding is that haplogroup A seems to be also original (like nearly everything) from South China/SE Asia:
Fig.10 Diffusion of the mitochondrial proto-A haplogroup. Blue clines stand for the total frequency, and red clines stand for the mutation rate within the population.
Notice that "proto-A" seems to mean A* rather than some pre-A standing between the N and A nodes. That's what I gather from the phylogenetic context in other figures but if anyone can clarify further, I'll be thankful.
Finally as the genetics of SE Asia and in particular Island SE Asia have been recently matter of lengthy discussions in this blog, I think that this map on ISEA N9 (N9a and Y2) may be interesting:
Fig.28 Distributions of the mitochondrial haplogroups Y2 and N9a in Southeast Asia. Blue stands for Y2, and red for N9a6.
But anyhow, take a look at the paper even if you can't speak Chinese because there are a lot of maps and phylogenetic graphs, all of them of interest.
One thing they have in common though: the spread of all lineages seems to begin in South China/SE Asia.