Parental influences on expression of glucose-6-phosphate dehydrogenase,G6pd, in the mouse; a case of imprinting

Abstract

SummaryGlucose-6-phosphate dehydrogenase (G6PD) activity was measured in blood from heterozygotes for the normal alleleG6pdaand the low activity alleleG6pda-m l Neu. In adult mice lower activity was found inG6pda/G6pda-m l Neuthan in the reciprocal heterozygoteG6pda-m l Neu/G6pda(the maternal allele being listed first). Thus, either the paternally derived allele was over-expressed or the maternally derived allele was under-expressed. By contrast, in younger mice the difference in G6PD activity in reciprocal crosses was less marked. The findings are interpreted in terms of differential imprinting of maternally and paternally inherited information. The explanation offered for age related differences is that, as a consequence of imprinting, either the paternal X-chromosome is preferentially reactivated, or cells in which the paternally derived allele is active are at a selective advantage, and proliferate better than those in which the maternally inherited allele is active.