I'd like to know why a microRNA could correspond to multiple ensembl gene IDs? For examples, we can see "hsa-mir-1302-2" corresponds to 4 ensembl gene IDs:
ensembl_gene_id gene_biotype ensembl_transcript_id mirbase_id
ENSG00000284332 miRNA ENST00000607096 hsa-mir-1302-2
ENSG00000284557 miRNA ENST00000408734 hsa-mir-1302-2
ENSG00000283921 miRNA ENST00000408365 hsa-mir-1302-2
ENSG00000283801 miRNA ENST00000408051 hsa-mir-1302-2
The GTF file is downloaded from: ftp://ftp.ensembl.org/pub/release-90/gtf/homo_sapiens/
Could any one please tell me why? I want to get the sequence length for each miRNA and it seems that I should not add up the length of all the transcripts together.