Way to filter out minor splicing variants

[alpae]

minor splicing variants appear as gene gains in terminal branches. implement feature to filter those out. see qustion on biostars: https://www.biostars.org/p/376689/

[alpae]

how to distinguish minor / major variants?

• same gene_id attribute --> same gene.
• used variant? encode specially? or check which variant is used? what about singletons that are not used?