approximate+number+of+transcripts+in+an+amount+of+RNA

average mouse transcript length: 2653 bp

5*"ng"*(1*"mol"*"bp"/(660E9*"ng"))*(6.02E23*"bp"/(1*"mol"*"bp"))*(1*"transcript"/(2653*"bp")) = 1.72E9*"transcript"

picture of equation here "C:\kurt\storage\CIM Research Folder\DR\2013\3-23-13\eq1.png"