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Author Topic:   Twitter Nerd-Fight Reveals a Long, Bizarre Scientific Feud
Taq
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Posts: 10075
Joined: 03-06-2009
Member Rating: 5.2


Message 10 of 16 (777803)
02-08-2016 5:49 PM
Reply to: Message 4 by Genomicus
02-06-2016 10:45 PM


Re: Twitter Nerd-Fight Reveals a Long, Bizarre Scientific Feud
Yeah, but the point is that they want authors to defend their use of non-parsimony methods on philosophical grounds, rather than scientific grounds. Which, you know, is kinda odd.
What type of scientific grounds would there be for non-parsimony method being better?
And they're adherence to parsimony comes across as kind of dogmatic.
Would it be fair to say that parsimony is the traditional gold standard? If so, I don't see why it would be dogmatic. It simply requires one test that all papers can have in common, in order to compare one data set with another.
As a comparison, I deal a lot with proteins. There are multiple ways of measuring protein concentrations, and different methods can produce significantly different for the same protein solution. It would actually be helpful if all publications required that at least a single method be used in all papers, while still allowing authors to report different values using different methods. I can understand why they would do it.

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 Message 4 by Genomicus, posted 02-06-2016 10:45 PM Genomicus has replied

Replies to this message:
 Message 12 by Genomicus, posted 02-08-2016 7:23 PM Taq has replied

  
Taq
Member
Posts: 10075
Joined: 03-06-2009
Member Rating: 5.2


Message 13 of 16 (777849)
02-10-2016 1:36 PM
Reply to: Message 12 by Genomicus
02-08-2016 7:23 PM


Re: Twitter Nerd-Fight Reveals a Long, Bizarre Scientific Feud
See Gadagkar and Kumar (2005) for an example of datasets where maximum likelihood is more appropriate than maximum parsimony.
Thanks for the example. Using computer simulations is something that should have donned on me from the start.
In the paper, they show that ML outperforms MP when there is a certain amount of heterotachy. Is there a way of determining the amount of heterotachy in a data set independent of the phylogenetic method?
Well, different phylogenetic methods are more appropriate depending on the data set. I hear you, Taq, but when it comes to molecular phylogenetics it's pretty hard to have an absolute standard given the diversity of sequences involved. So, for example, I've published molecular phylogenies of certain gram-positive protein systems, but opted to use more than one phylogenetic method (ML and Bayesian analysis) to see the extent to which the phylogenies were congruent.
I totally get what you are saying. Going back to my protein assay analogy, the appropriate method can also depend on the protein mixture. If you have an nearly pure sample with just one protein in it, then you can very precisely and reliably measure the concentration of the protein by using UV absorbance since specific amino acids have specific absorbances. If you have an unknown mix of proteins you can't say how many UV absorbing amino acids there are per protein molecule, so the UV method may not be as appropriate.
So, for example, I've published molecular phylogenies of certain gram-positive protein systems, but opted to use more than one phylogenetic method (ML and Bayesian analysis) to see the extent to which the phylogenies were congruent.
By congruence, do you mean congruence to the accepted species tree? If so, are you assuming a lack of horizontal transfer?

This message is a reply to:
 Message 12 by Genomicus, posted 02-08-2016 7:23 PM Genomicus has replied

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