Zygote formation

An important feamre of human mitochondrial mtDNA is that—because aU mitochondria are contributed by the ovum during zygote formation—it is transmitted by maternal nonmendefian inheritance. 

Lee, C.-C. (1975) Dirofilaria immitis. ultrastructural aspects of oocyte development and zygote formation. Experimental Parasitology 37, 449-468. 

Vegetative cells of C. reinhardtii differentiate in gametes upon nitrogen starvation. Crosses between gametes of opposite mating type then lead to zygote formation and subsequent meiosis. 

Martinez-Salas, E., Linney, E., Hassell, J., and DePamphilis, M. L. (1989). The need for enhancers in gene expression first appears during mouse development with formation of the zygotic nucleus. Genes Dev. 3 1493-1506. 

In the formation of the zygote, all mitochondria are contributed by the ovum. Therefore, mtDNA is transmitted by maternal inheritance in a vertical, nonmendelian fashion. Strictly maternal transmission of mtDNA has been documented in humans by studies of restriction fragment length polymorphisms (RFLPs) in DNA from platelets. As exemplified by the disorders outlined above,... 

Conception The onset of pregnancy, marked by implantation of the blastocyst the formation of a viable zygote. [EU]... 

Segment I the early embryonic development (fertilized egg or zygote, prior to implantation and prior to formation of the three primary germ layers),... 

Simpson, P. (1983). Matemal-zygotic gene interactions during formation of the dorsoventral pattern in Drosophila embryos. Genetics 705 615-632. 

The expression of a somatic form of histone HI could constitute one component of the transcriptionally repressive state. The biogenesis of a mature nucleosome is associated with the formation of transcriptionally repressive chromatin. While the association of DNA with histones H3 and H4 can generate a nucleosomelike structure, the DNA can still readily interact with transcription factors. This ability is diminished with the further incorporation of histones H2A and H2B that results in the formation of a nucleosome that can exclude the binding of basic components of the transcription machinery (e.g., RNA polymerase II). The formation of a truly transcriptionally repressive chromatin structure is brought about by the addition of histone HI, which can be incorporated only after the addition of histones H2A and H2B and causes chromatin to condense into a 30-nm fiber (Bouvet et al., 1994). The requirement for an enhancer for efficient promoter utilization in zygotic nuclei, but not the pronuclei, could reflect the developmental acquisition of chromatin con-... 

The first Wnt responsive target gene to be identified in vertebrates was the Xenopus zygotic gene, Siamois, which plays a crucial role in dorsal axis formation in the developing embryo (Brannon et al., 1997). Siamois was... 

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