hello
I am just reading a web page related about dna strand to understand dna strand.(I think it is so confused..)
but I can't understand the context of web pagel.
below is the context of web pages i searched in.
(I can't figure out the second paragraph... why reading both of the strand from respective 3' ends at one result the uninterpretable?)
Does anyone help me understand the below contents?
Sequencing by synthesis, which is how most commercially available high-throughput sequencing technologies work as of December 2012 (see notes on sequencing technologies), always synthesizes the new strand (which becomes your read) in a 5'-to-3' direction. That's because this is how DNA polymerase works in our cells (indeed, in every living thing's cells) and sequencing relies on DNA polymerase. Since the new strand is synthesized 5'-to-3', you are working your way up the template strand in a 3'-to-5' direction.
In any sequencing technology, you PCR amplify the individual DNA fragments once they have hybridized to flowcells or beads. This means you end up with both strands of DNA. If you were to read both of the strands from their respective 3' ends at once, you'd be getting two different sequences and your results would be uninterpretable. To avoid this problem, sequencing technologies ligate non-complementary adapters to the 3' and 5' ends of DNA fragments so that the primer for one adapter only begins synthesis on one strand and not on its complement.