def index(self, overwrite=False):
        """
        Assuming that all necessary data for this Genome has been downloaded,
        generate the GTF database and save efficient representation of
        FASTA sequence files.
        """
        if self.requires_gtf:
            self.db.connect_or_create(overwrite=overwrite)
        if self.requires_transcript_fasta:
            self.transcript_sequences.index(overwrite=overwrite)
        if self.requires_protein_fasta:
            self.protein_sequences.index(overwrite=overwrite)
Assuming that all necessary data for this Genome has been downloaded,
        generate the GTF database and save efficient representation of
        FASTA sequence files.