miRNA family - (Aug/22/2008 )

Dear all,

Hi, can anyone tell me what is the criteria to determine the family of a microRNA? Can u plz suggest me journals or other references that have clear explanation on this.

And, do microRNA precursor (pre-miRNA) have polyA tail like that primary microRNA (pri-miRNA)

Thanx..

Gooogle the defination for microRNA family
Pre-miRNAs have been processed to around 70 bp hairpin 2nd structure product, I do not think they have polyA tail.