Question about Phylogenetic Trees generated by MEGA 4.0

[twinmomma]

Hi,
I'm new to this forum and I joined because I have a pretty specific` question. I'm creating some phylogenetic trees from sequences from bacteria that I grow, and I'm a bit confused as to what the line shown at the bottom of the tree means. I've uploaded an attached pic. I know its a scale of some sort, probably evolutionary distance, but I just wondered if anyone could clarify for me? If anyone has used the program MEGA that would help as well.

twinmomma

Sulfur Oxidizer Tree December 4 07 - Bootstrapped - concensus tree.TIF

(5.3 MB) Downloaded 24 times

[mith]

Hard to say, I've used this program and I think there's a way to toggle distances(line length reflects distance), check that to see if the bar length changes with it.