English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Active demethylation of the paternal genome but not of the maternal genome occurs in fertilized mouse, rat, pig, and bovine zygotes. To study whether this early demethylation wave is important for embryonic development, we have analyzed the global methylation patterns of both in vivo-fertilized and cloned rabbit embryos. Anti-5-methylcytosine immunofluorescence of in vivo-fertilized rabbit embryos revealed that the equally high methylation levels of the paternal and maternal genomes are largely maintained from the zygote up to the 16-cell stage. The lack of detectable methylation changes in rabbit preimplantation embryos suggests that genome-wide demethylation is not an obligatory requirement for epigenetic reprogramming. The methylation patterns of embryos derived from fibroblast and cumulus cell nuclear transfer were similar to those of in vivo-fertilized rabbit embryos. Fluorescence in situ hybridization with chromosome-specific BACs demonstrated significantly increased chromosomal aneuploidy rates in cumulus cell nuclear transfer rabbit embryos and embryos derived from nuclear transfer of rabbit fibroblasts into bovine oocytes compared with in vivo-fertilized rabbit embryos. The incidence of chromosomal abnormalities was correlated with subsequent developmental failure. We propose that postzygotic mitotic errors are one important explanation of why mammalian cloning often fails.

Methylation Reprogramming and Chromosomal Aneuploidy in In Vivo Fertilized and Cloned Rabbit Preimplantation Embryos1