the meaning of Match Position for reads?

[beliefbio]

hi ^_^

In the s_N_export.txt file, If the Match Position for one read is x, should the other end position of this read be x+75 both for "F" forward and "R" reverse strand match? (75 is the read length) Now we try x-75 for the reads matching "R" reverse strand and get some negative number position. So there must be mistake in x-75.

Thank you for your time!

[kmcarr]

The position reported is always the left-most end of the alignment, whether the alignment is in the forward or reverse orientation.

[beliefbio]

Thanks so much!!