stripping adaptors and/or merging paired reads of DNA sequences with overlap
SeqPrep is a program to merge paired end Illumina reads that are overlapping
into a single longer read. It may also just be used for its adapter trimming
feature without doing any paired end overlap. When an adapter sequence is
present, that means that the two reads must overlap (in most cases) so they
are forcefully merged. When reads do not have adapter sequence they must be
treated with care when doing the merging, so a much more specific approach is
taken. The default parameters were chosen with specificity in mind, so that
they could be ran on libraries where very few reads are expected to overlap.
It is always safest though to save the overlapping procedure for libraries
where you have some prior knowledge that a significant portion of the reads
will have some overlap.