What are DNA TAGs - Basic background knowledge (Aug/01/2006 )

Can anyone tell me what is the meaning of DNA TAGs?

i can't seem to find it anywhere on the internet

thx in advance

DNA tags are short nucleotide sequences which make it possible to identify genes which have been affected by mutagensis by PCR. (As far as I know this is mainly used in Arabidopsis) But I have also heard it as a generic term for GAL4-binding domain, Lac-Operator, etc.. so I guess the context is important.

The term "tag" is commonly used for an oligo that is attached to another oligo that is sequence specific. The sequence-specific part is hybridised to a PCR product or cDNA or whatever and may then be extended with labelled ddNTPs to identify a SNP. The tag part is then hybidised to a complementary sequence on a chip or bead or whatever to isolate the labelled product, which is then detected. Many genotyping assays use this method. The term can be generally used to identify some structure that is used to isolate DNA or proteins (eg. His-tag or GST-tag in the case of proteins).