To evaluate expression differences between the B6 and D2 alleles (B and D, respectively), we measured allelic expression in F1 hybrids using a combination of RT-PCR and a single-base primer extension technique (SNaPshot, Applied Biosystems, www.appliedbiosystems.com). Primer 335 was used to design a pair of PCR primers that target sequences on the same exon and flanking an informative single-nucleotide polymorphism (SNP).
