I have some RNA sequencing reads to align to the human reference genome. I found the genome FASTA files on both [GENCODE][1] and [ENSEMBL][2]: `GRCh38.p13.genome.fa.gz` and `Homo_sapiens.GRCh38.dna.toplevel.fa.gz` 
But after unzipping them, I found that they are 3.1G and 60G respectively. Why is that? And which one should I use? (considering the purpose of the project is to detect gene fusion from the sequencing reads).


  [1]: http://ftp.ebi.ac.uk/pub/databases/gencode/Gencode_human/release_38/
  [2]: http://ftp.ensembl.org/pub/release-104/fasta/homo_sapiens/dna/
https://www.biostars.org/p/487975/