[R-sig-phylo] Bootstrap values and NJ when there is no genetic distance between samples

2011-05-05 Thread Alastair Potts
Good day all, I noticed something that I would consider an anomaly when analysing one of my trees with NJ. A 'polytomy' of samples contained many bootstrap values of 100 between samples. I was looking at the total change in bootstrap values for all nodes when I picked this up (as the signal in

Re: [R-sig-phylo] Bootstrap values and NJ when there is no genetic distance between samples

2011-05-05 Thread Klaus Schliep
Hi Alastair, it is not that surprising. NJ normally does not produce poytomies, just edge weights of length 0. How these are broken may depends from the input order (from labels in the distance matrix like in this implementation) or could be broken randomly. I added some code below to highlight i

Re: [R-sig-phylo] Bootstrap values and NJ when there is no genetic distance between samples

2011-05-05 Thread Joe Felsenstein
Klaus Schliep wrote -- > it is not that surprising. NJ normally does not produce poytomies, > just edge weights of length 0. How these are broken may depends from > the input order (from labels in the distance matrix like in this > implementation) or could be broken randomly. I added some code b

[R-sig-phylo] Session on Phylogenetic Approaches to Paleobiology at GSA 2011

2011-05-05 Thread David Bapst
Hello all, I just wanted to let the readers of this list know about a technical session that may be of general interest, at this year's Geological Society of America 2011, which will be held in Minneapolis, 9-12 October 2011. This session, which was proposed by my colleague Emily King and I, will f

Re: [R-sig-phylo] Bootstrap values and NJ when there is no genetic distance between samples

2011-05-05 Thread Alastair Potts
Hi Klaus and Joe, Thanks very much for your responses. From Klaus: it is not that surprising. NJ normally does not produce poytomies, just edge weights of length 0. How these are broken may depends from the input order (from labels in the distance matrix like in this implementation) or could be