Spike sequence for ERANGE

[pibbo]

Hi everyone,

I am new in this field and recently I use ERANGE to do some RNAseq experiments. It is mentioned in the manual (readme.build-rds) that a splice fasta file and a spikes fasta file are required to build expanded genomes. I have already build the splice fasta file by using getsplicefa.py. However, I am confused about what "spikes fasta file" is and where can i get it. And What is the purpose to use them? After I get it, how can I generate expanded genomes by using bowtie-build?

Thank you very much!!