I have question about RNA-seq data(exactly speaking, it is eCLIP-seq). For different library types, I heard FASTQ sequence is complementary with original RNAs. If so, is there any possibility of mapping opposite strand? I made a bigwig file to watch in UCSC genome browser. But some of genes seem to be expressed opposite strand. How can I figure out whether FASTQ sequences is the same of original RNAs or not?