Difference between UPGMA and the NJ

Question

[l.roca]

Hi,

I understand how UPGMA works but I do not know what is the difference between it and the NJ method and how NJ works.

I am not a mathematician so a simple but extensive explanation, links, etc are welcome.

Thanks

[David W]

Wikipedia has a pretty straightforward explanation/illustration of NJ -- http://en.wikipedia.org/wiki/Neighbor_joining. Can you make your question more specific by saying what you are still missing having read this?