Oocyte Maturation and Fertilization: A Long History for a Short Event

Indexed in: Chemical Abstracts, EBSCO.

Events of reproduction occurring from meiotic resumption of the immature oocyte up to its exit from the second meiotic block following activation will be revealed. Morphological modifications of the ...
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Current State of the Art in Large Animal Cloning: Any Lesson?

Pp. 149-155 (7)

Pasqualino Loi and Grazyna Ptak


Following fertilisation, major changes occur in the organisation of chromosomes and genes in the zygote that contributes to the formation of totipotent cells and their ensuing differentiation to the diverse cell lineages in the organism. The aim of animal cloning through Somatic Cell Nuclear Transfer (SCNT) is to reestablish the reprogramming that occurs in the fertilized embryo. SNCT often leads to abnormal development with a majority of concepti lost before birth. Imprinted genes are amongst the most frequently affected genes, and their altered expression could in part explain the observed developmental phenotypes. Here, we report our experience in sheep cloning. We describe the major phenotypic abnormalities observed in the extraembryonic tissues of sheep clones and suggest some possible strategies to improve SCNT.


Department of Comparative Biomedical Sciences, University of Teramo, Italy.