Rr143^tm1.1Sson

A single G-to-A base change was introduced in the CpG island in intron 1 of the Igf2 gene splice variant with the most upstream exon 1. LoxP sites were inserted around the CpG island and an FRT flanked neomycin resistance gene cassette was inserted via homologous recombination. Flp-mediated recombination removed the neo cassette. (J:265506)