Dear BioStar Leaders,
I understand that 5' prime and 3' prime represent the open end of the DNA molecule, i.e. the carbon atom position in the deoxyribose sugar molecule of nucleotide bases(A,T,G,C) and also they help provide the directionality of sequencing.
I know that illumina named the oligo sequences as P5 and P7 that enables adapters to bind to FlowCell in bridge amplification step, where P probably stands for Primer, and my question is why did they choose numbers 5 and 7 ? and what do they mean ?
Similarly, why did they choose numbers 5 and 7 for sample index oligo sequences i5 and i7 ?
Thanks, gsr
Good question. It may be just a coincidence. I have not heard of a specific provenance for those numbers. It is one of those things that may be written up one day by someone who was originally involved with the invention of solexa chemistry magic. Many still don't realize that p7 indexes = Index 1.
thank you for the answer @genomax