Differential activity of maternally and paternally derived chromosome regions in mice

Abstract

Although both parental sexes contribute equivalent genetic information to the zygote, in mammals this information is not necessarily functionally equivalent. Diploid parthenotes possessing two maternal genomes are generally inviable, embryos possessing two paternal genomes in man may form hydatidiform moles, and nuclear transplantation experiments in mice have shown that both parental genomes are necessary for complete embryogenesis. Not all of the genome is involved in these parental effects, however, because zygotes with maternal or paternal disomy for chromosomes 1, 4, 5, 9, 13, 14 and 15 of the mouse survive normally. On the other hand, only the maternal X chromosome is active in mouse extraembryonic membranes, maternal disomy 6 is lethal, while non-complementation of maternal duplication/paternal deficiency or its reciprocal for regions of chromosome 2, 8 and 17 has been recognized. We report that animals with maternal duplication/paternal deficiency and its reciprocal for each of two particular chromosome regions show anomalous phenotypes which depart from normal in opposite directions, suggesting a differential functioning of gene loci within these regions. A further example of non-complementation lethality is also reported.

Maternal UPD 20 in a hyperactive child with severe growth retardation

“…26 Intrauterine growth retardation in our case 27 Two of them have been associated with a distal region of mouse chromosome 2, which shows homology with human chromosome 20. 28,29 Here, paternal UPD of this region led to hyperactivity and a short and broad body shape. Maternal UPD instead resulted in a counter type, totally inactive mice with a long and flat body.…”

Genomic imprinting and its relevance to genetic diseases

“…However, this complementation rule is not applied to several chromosomal regions. For example, maternal UPD mice for a proximal region of mouse chromosome 11 show growth deficiency, while paternal UPD mice for the same region represent overgrowth (Cattanach and Kirk, 1985). The maternal UPD mouse for a distal region of chromosome 7 shows lethal growth deficiency, and the paternal UPD mouse dies at an earlier stage (Ferguson-Smith et al, 1991).…”

Parental Allele-Specific Chromatin Configuration in a Boundary–Imprinting-Control Element Upstream of the Mouse H19 Gene

“…In mammals, the maternal and paternal genomes are both required for normal development (8,37,48). Their functional nonequivalence is mediated by genomic imprinting, an epigenetic mechanism that gives rise to differential expression of the maternal and paternal alleles of certain genes.…”