How are the reads assigned to genes in strand-specific RNAseq libraries?

Question

[Sib]

Hello Biostars,

I know that the benefit of strand-specific libraries is that we can assign the reads that fall into the overlap of the genes of the two DNA strands. I want to explain it by examples in forward-stranded and reverse-stranded libraries. So I have provided the following schema and I would be grateful if you could tell me if my explanation is correct:

According to the schema:

• In a forward-stranded library, reads mostly map on the same strand as the genes.

  So,

  Condition 1: If the direction of the read is forward, it can be concluded that the read should be assigned to the forward DNA strand (gene 1).

  Condition 2: If the direction of the read is reverse, the read should be assigned to the reverse DNA strand (gene 2).

• In a reverse-stranded library, reads mostly map on the opposite strand as the genes.

  So,

  Condition 3: If the direction of the read is forward, it can be concluded that the read should be assigned to the reverse DNA strand (gene 2).

  Condition 4: If the direction of the read is reverse, it can be concluded that the read should be assigned to the forward DNA strand (gene 1).

I would appreciate it if you could tell me whether I am correct or not.