MantisBT - MEGA
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0001148MEGADistance Data Explorerpublic2019-03-12 00:092019-03-18 08:18
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gstecher 
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Zhentao
Cheng
zhentao.cheng0123@gmail.com
zhentao.cheng0123@gmail.com
0001148: With the increase in the number of sequences, the pairwise distances are different.(MEGA 7)
While I was calculating the pairwise distances of a FASTA file which including 44 families and 870 sequences, I found if I calculate every family separately, the pairwise distances of same sequences may be different.
For example, the distance between “Cinara pilicornis|ACEA154-14” and “Cinara pilicornis|GBMHH3689-14” is 0.036 in “Aphididae-14.fas” (including 44 families and 870 sequences) and 0.064 in ”Cinara pilicornis.fas” (only one family, 30 sequences).
Input Data(Data Type: "Nucleotide Sequences" )
Select Genetic Code ("Standard")
Compute Pairwise Distances(Variance Estimation Method:"None";Substitutions type:"Nucleotide";Model/Method:"Kimura 2-parameter model")
Export to CSV formatted file(Export Type:"Column")
MEGA Version 7.0.26
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rar Upload File.rar (87,639) 2019-03-12 00:09
https://megasoftware.net/mantis_bt/
Issue History
2019-03-12 00:09guestNew Issue
2019-03-12 00:09guestFile Added: Upload File.rar
2019-03-18 08:04gstecherNote Deleted: 0001059
2019-03-18 08:04gstecherFile Deleted: ANTcrustaceans_Complete5.mas
2019-03-18 08:18gstecherNote Added: 0004207
2019-03-18 08:18gstecherStatusnew => resolved
2019-03-18 08:18gstecherResolutionopen => no change required
2019-03-18 08:18gstecherAssigned To => gstecher

Notes
(0004207)
gstecher   
2019-03-18 08:18   
Hi Zhentao,

I am writing in response to your question regarding the MEGA software. The difference in pairwise distances you reported happen because you are using the 'Complete Deletion' option so the data subset used is different between the files. You can use the 'Pairwise Deletion' option if you expect the distances to be the same when using the two input files.

--
Best regards,
Glen Stecher
Institute for Genomics and Evolutionary Medicine
igem.temple.edu