The regions of overlap between reads are used to later assemble and align the reads to a reference genome to reconstruct the full genomic sequence. After removing the indexing information at the front of read 1 sequences, the read 1 and read 2 sequences are now of different lengths. A Resource At Your Fingertips Sequencing 5th Grade Classroom School Reading Sequencing read lengths correspond directly to the sequencing reagents used. Paired end sequencing read length . However, all the read 1 sequences contain an 8 bp cell barcode, an 8 bp umi, and a poly t region while the read 2 sequences are simply coding sequence. A good choice for read length is closely tied to the insert size of the sequencing library, i.e., how long the individual dna fragments are that are sequenced. Sequencing technologies vary in the length of reads produced. Index adapter sequences are eight or 10 bases long. Maximum supported read length for sequencing platforms and sbs reagent kits. The number ...