Missing ',' in line when Biopython reads a nexus tree - bioinformatics

Question

I want to edit a tree that I got from BEAST2 treeannotator in nexus-format.
Usually I use the module Phylo from Biopython for such work but Phylo.read(r"filename.tree", "nexus") gave me the next exception:
---------------------------------------------------------------------------
NexusError Traceback (most recent call last)
Input In [29], in <cell line: 1>()
----> 1 Phylo.read(r"filename.tree", "nexus")
File ~\miniconda3\lib\site-packages\Bio\Phylo\_io.py:60, in read(file, format, **kwargs)
58 try:
59 tree_gen = parse(file, format, **kwargs)
---> 60 tree = next(tree_gen)
61 except StopIteration:
62 raise ValueError("There are no trees in this file.") from None
File ~\miniconda3\lib\site-packages\Bio\Phylo\_io.py:49, in parse(file, format, **kwargs)
34 """Parse a file iteratively, and yield each of the trees it contains.
35
36 If a file only contains one tree, this still returns an iterable object that
(...)
46
47 """
48 with File.as_handle(file) as fp:
---> 49 yield from getattr(supported_formats[format], "parse")(fp, **kwargs)
File ~\miniconda3\lib\site-packages\Bio\Phylo\NexusIO.py:40, in parse(handle)
32 def parse(handle):
33 """Parse the trees in a Nexus file.
34
35 Uses the old Nexus.Trees parser to extract the trees, converts them back to
(...)
38 eventually change Nexus to use the new NewickIO parser directly.)
39 """
---> 40 nex = Nexus.Nexus(handle)
42 # NB: Once Nexus.Trees is modified to use Tree.Newick objects, do this:
43 # return iter(nex.trees)
44 # Until then, convert the Nexus.Trees.Tree object hierarchy:
45 def node2clade(nxtree, node):
File ~\miniconda3\lib\site-packages\Bio\Nexus\Nexus.py:668, in Nexus.__init__(self, input)
665 self.options["gapmode"] = "missing"
667 if input:
--> 668 self.read(input)
669 else:
670 self.read(DEFAULTNEXUS)
File ~\miniconda3\lib\site-packages\Bio\Nexus\Nexus.py:718, in Nexus.read(self, input)
716 break
717 if title in KNOWN_NEXUS_BLOCKS:
--> 718 self._parse_nexus_block(title, contents)
719 else:
720 self._unknown_nexus_block(title, contents)
File ~\miniconda3\lib\site-packages\Bio\Nexus\Nexus.py:759, in Nexus._parse_nexus_block(self, title, contents)
757 for line in block.commandlines:
758 try:
--> 759 getattr(self, "_" + line.command)(line.options)
760 except AttributeError:
761 raise NexusError("Unknown command: %s " % line.command) from None
File ~\miniconda3\lib\site-packages\Bio\Nexus\Nexus.py:1144, in Nexus._translate(self, options)
1142 break
1143 elif c != ",":
-> 1144 raise NexusError("Missing ',' in line %s." % options)
1145 except NexusError:
1146 raise
NexusError: Missing ',' in line 1 AB298157.1_2015_-7.9133750332192605_114.8086828279248, 2 AB298158.1_2007_-8.41698974207…
Using Nexus.read(Nexus(), input=r"filename.tree") gave the same result. Please could anyone help with this? I cannot understand the reason of this error because nexus file looks correct.

Answer 1

The reason is that Biopython cannot read nexus trees with links, constituent from translations & a newick tree. So it is required previously to convert this to the form with full names into the tree (as hereinbelow).
Begin
tree TREE1 = (((your,tree),(in,(the, newick))),format);
End;
P.S. It is allowed in the newick format to surround the label with quotes, & some programmes or scripts add them to those names that have ambiguous characters. But it can lead to exceptions during the following phylogenetic analysis, for instance, in BEAST. I wish you would be careful with this.