Using gff format in IGV 1 Do not…

Using gff format in IGV.

1. Do not omit the first line, especially for GFF 3.
As IGV supports both of GFF ver 2 and GFF ver 3, the file needs to be distinguished.
Do not miss the first line

##gff-version    3

2. Make sure tab is used to separate fields.
Even for the first line, there must be a tab between gff-version and 3.
No space.

Here are the specifications.

GFF version 2
http://www.sanger.ac.uk/resources/software/gff/spec.html

GFF version 3
http://www.sequenceontology.org/gff3.shtml