BIOL 3P34 Lecture Notes - Lecture 9: Trophoblast, Hypoblast, Twin
8 Jan 2018
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Document Summary
Fusion occurs when the sperm enters the membrane, not the zona felusida(?) Hormones are given to allow oocyte to mature, mixed with sperm. Expansion due to water caused by sodium ions. Genomes of male and female fuse together, become active. Required by oocyte to allow cleavages and activation to occur, rather than depend on zygotic resources. But when the embryo grows, the maternal rna decreases, and the zygotic rna increases. It"s the dad genomes that activates the zygotic rna. His genome is activated first, methylation (high methylation, low transcription). Highly methylated when germ cells reaching the gonad. methylation decreases quickly, especially in male, during fertilization, since transcription is needed when combining genome. Female will catch up and go under low methylation. From morula, methylation increases and transcription decreases, locking cells to specific cell types. The blackline is the imprint of gene, plays in development. Some genes are only contributed to maternal or paternal genome.
