Article Abstract:
Cytosine methylation has been studied with regard to unequal developmental potentials of the oocyte and sperm genomes. Cytosine methylation interferes with promoters of genes with postzygotic aging in mice.Development of uniparental mouse embryos is always abortive whether the embryo is an androgenote or a gynogenote. Genomic imprinting must have two identical or almost identical DNA sequences showing very unequal levels of expression over a long period. The means by which specific sequences are designated for de novo methylation in a germ line or somatic tissues is not well understood, but it seems there are some developmental windows in which demethylation and de novo methylation may set up allele-specific methylation patterns at imprinted loci.
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Article Abstract:
The overall pathway by which vasculature develops is reviewed and related to cardiovascular malformations, which appear in numerous hereditary diseases and other diseases. Etiology of a number of groups of diseases in which cardiovascular maintenance or development functions in an abnormal way is discussed. The zebrafish is more often serving as a model genetic organism useful in the study of the development of the circulatory system. Morphogenesis in the heart and vascular system involves challenges somewhat like corresponding events in the body in other places. Some regulatory pathways seem to be shared.
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Article Abstract:
Two Lefty (ital) homologues, LEFTY A (ital) and LEFTY B (ital), have been characterized. They are four exons each, spliced at the same positions and about 50 kb apart on chromosome 1q42. It had been hypothesized that Lefty (ital) mutations are associated with human left-right (LR)-axis malformations. The transforming growth factor (TGF)--beta family of cell-signaling molecules has been implicated in mammalian LR axis development. Two family members, Lefty1 (ital) and Lefty 2 (ital) are expressed only on the left side of the mouse embryo by 8.0 days post coitum.
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