Note that for each segment of double-stranded DNA, there will possibly be two sets of sense and antisense, depending on which direction one reads (since sense and antisense is relative to perspective). It is ultimately the gene product, or mRNA, that dictates which strand of one segment of dsDNA we call sense or antisense. But keep in mind that sometimes, such as in prokaryotes, overlapping genes on opposite strands means the sense for one mRNA can be the antisense for another mRNA. The immediate product of this transcription is a resultant initial RNA transcript, which contains a sequence of nucleotides that is identical to that of the sense strand. The exception to this is that
uracil is used for nucleotide sequencing of RNA molecules rather than
thymine. Most
eukaryotic RNA transcripts undergo
additional editing prior to being translated for protein synthesis. This process typically involves the addition of a methylated
guanine nucleotide
cap at the 5' end, the addition of a
poly-A tail at the 3' end, and the removal of
introns from the initial RNA transcript (
RNA splicing). The end product is known as a mature
mRNA. Prokaryotic mRNA does not undergo the same process. Strictly speaking, only the mRNA makes "sense" with the genetic code, as the translated protein
peptide sequence can be directly inferred from this strand. The "antisense" strand of DNA is complementary to the "sense" strand and is the actual template for mRNA synthesis. ==Application==