The U01 replaces the UH2/UH3 so it has more flexibility and GWAS can now be performed.
“The Identification of Gene Variants for Addiction Related Traits by Next-Gen Sequencing in Model Organisms Selectively Bred for Addiction Traits (UH2/UH3)” FOA and Notice of Change are now published. Please see the links below:
http://grants.nih.gov/grants/guide/notice-files/NOT-DA-15-042.html