Dear Joe Felsenstein,
thank you very much for your reply! And the helpfull advice how to run
it with just 3 sequences.
Regards,
Janosch
> This is a "feature" of Fitch. You get no result if you have only
> three sequences. You need at least 4. My apologies for this
> poor behavior. However with three sequenceds there is only one
> possible tree topology (a single interior node connected to all
> three). You can draw the tree by hand. It is:
>> (putida:x,LB400:y,HD100:z);
>> putida 0.000000 0.713185 3.438244
> >LB400 0.713185 0.000000 3.052331
> >HD100 3.438244 3.052331 0.000000
>> >
> where the three numbers x, y, and z are given by
>> x = (1/2)(0.713185+3.438244-3.052331) = 0.549549
>> y = (1/2)(0.713185+3.052331-3.438244) = 0.163636
>> z = (1/2)(3.438244+3.052331-0.713185) = 2.888695
>> If you run Neighbor you will get this tree, as Neighbor allows trees as
> small as three species. The fit is perfect in either case (as there are
> three branch lengths being used to explain three distances.
