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Old 01-13-2011, 08:27 AM   #1
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Location: az

Join Date: Jan 2009
Posts: 9
Default Why is ML/NJ phylogeny different from SNP tree?


I am working on a bacterial genome. We have determined the complete genome sequence of this genome and want to study the evolutionary relationship of my genome and its VERY CLOSE relatives (within the same species).

I need to construct a tree for these genomes.

First, I generated a tree based on the number of SNPS detected in conserved genomic region (~80% of whole genome).

I also constructed trees based on the conserved genomic sequence using ML and NJ methods. The two trees with ML and NJ have the same topology.

When I compared the ML/NJ trees with the SNP tree, it shows the different phylogenetic relationship of some genomes.

When I checked the published papers, it seems most studies like inferring trees using the number of SNPs, especially for the very closed genomes. I think the ML/NJ trees based on the sequence information should be much better than the number of SNPs.

We got two trees with different topologies. I couldn't get a reason for the difference. Does anybody have any comments? which tree should I use? how to explain the difference?

Many thanks,
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