strandedness of probesets

Question

[hosseinkhan]

Hi,

I want to know if in bacterial genomes the genes are located on the same strand;i.e. just sense or antisense; or like Eukaryotic genomes they either might be located on the sense or antisense strands. I asked it because in an annotation file of an affymetrix chip the orientation of all probes has been recorded as antisense and it seems strange to me.

thanks

Answer 1

[Istvan Albert]

Makes sure you are using the terminology correctly. Sense (and anti-sense) indicate the protein coding direction of the DNA and have nothing to do with the forward or reverse strands that you seem to imply.

The wikipedia page says:

The DNA sense strand looks like the messenger RNA (mRNA) and can be used to read the expected protein code by human eyes (e.g. ATG codon = Methionine amino acid). However, the DNA sense strand itself is not used to make protein by the cell. It is the DNA antisense strand which serves as the source for the protein code, because, with bases complementary to the DNA sense strand, it is used as a template for the mRNA