Figure 1

Imprinting analysis of metatherian orthologues of eutherian imprinted genes in M. domestica. The five gray short-tailed opossum genes investigated are ( A ) PLAGL1, ( B ) COPG2, ( C ) IMPACT, ( D ) L3MBTL and ( E ) HTR2A. The arrow denotes the polymorphism used to determine the imprint status of the gene. PLAGL1 (n = 2), COPG2 (n = 2), and IMPACT (n = 2) are not imprinted since the polymorphism is present in both the genomic DNA and the cDNA. In contrast, L3MBTL (n = 4) and HTR2A (n = 3) are imprinted since the genomic polymorphism is absent in the cDNA, demonstrating that only one allele is expressed. Using those samples where the offspring are heterozygous and the mothers are homozygous at the same polymorphic site, it was determined that L3MBTL and HTR2A were expressed from the paternal and maternal alleles, respectively.