Polymorphic morphological characters in TNT

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Tommercury

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Jul 24, 2020, 8:12:11 AM7/24/20
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Dear everyone,

I have some morphological data. I notice in some papers, they said TNT treat polymorphism as question marks. However, I analysed my data including polymorphic characters (different states in brackets) and without them (coded as question marks). The results are different, with the tree including polymorphic characters being slighter larger in tree length. Therefore I want to know how does TNT treat polymorphic characters? Which code method should I adopt?

Thank you very much!!

Tom

Martín Ramírez

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Jul 24, 2020, 8:49:34 AM7/24/20
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Hi Tom,

For a binary character, the polymorphism [01] is equivalent to ?. You probably have a multistate character with an incomplete polymorphism. For example, [12], which produces a change [0] to [12] somewhere in the tree.

For a three state character, [012] = ?, and so on.

Cheers, 

Martin

Tommercury

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Jul 25, 2020, 8:17:12 PM7/25/20
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Dear Martin,

Thank you very much for your help! So for an unordered character having three states, if there is a change from 0 to [02], it will be of zero step, but if it changes from 0 to [12], it will need one step, is that true?

Best wishes,
Tom

在 2020年7月24日星期五 UTC+8下午8:49:34,Martín Ramírez写道:

Wesley Colombo

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Jul 26, 2020, 7:08:52 PM7/26/20
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Dear Tom,

I think there are three other possible ways of encoding polymorphism:

1 - Putting the polymorphic condition as character and presence/absence as states. 
For example: I work with a group of parasitoid wasps that exist species with apteros, micropterous and macropterous forms. Then you can insert a wing polymorphism as character, and present/absent as states;

2 - You can also separate all polymorphic forms as characters and then the present/absent states. Following the example above, the character 01: macropterous (present/absent), character 02: micropterous (present/absent) and character 03: macropterous (present/absent). 

3 - Finally, you can put as character the polymorphic structure and the states as the variants of that structure and mark how many variants are needed. For example: character "wing development" and states: (1) apterous, (2) micropterous and (3) macropterous. Finally, if a terminal has the three polymorphic forms, you will code in this character as being (1, 2, 3).

I am not particularly able to say which is the most effective or which is correct, however, all possibilities are. Attached, I send you a paper that can help you.

All the best,

Wesley Dondoni Colombo
Ciências Biológicas (Biologia Animal)
Universidade Federal do Espírito Santo - Brazil
http://lattes.cnpq.br/5098517861351467

"Two things are infinite: the universe and human stupidity; and I'm not sure about the universe" (Einstein)


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Kornet_&_Turner_1999[polymorphism].pdf
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