Fig. 3. Bi-allelic expression of HUC2 in mouse and human. (A) Tru9I polymorphism in the mouse HUC2 sequence between 129/Sv and M. spretus strains was used to analyse allele-specific expression by RT-PCR in 13.5dpc embryos, as described in Fig. 2. (B) In three separate embryos (1-3), transcription from mouse HUC2 was detected from both parental alleles. The pattern was the same as that from genomic DNA of the F1 hybrid (129/Sv x M. spretus). (C) DdeI polymorphism in the human HUC2 sequence was identified in the genomic DNA of parents in two independent families. (D) RT-PCR analysis was performed on total RNA isolated from post-partum placentas from these families. This demonstrated bi-allelic expression of human HUC2 in placenta (RT+). The pattern was the same as that from genomic DNA of the placental tissue (gDNA).