Embryonic gene activation is a process by which the embryo begins to transcribe its newly formed genome.As the embryonic gene activation occurs during early stages the paternal genome may not have any influence at that stage.

Now, My question is why does only the maternal genome play a role in embryonic gene activation? Does paternal genome have a role in prior/post embryonic genome activation?

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    $\begingroup$ It would be great if you provide a few reference links. $\endgroup$
    – Shefali
    Jan 4, 2014 at 4:37
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    $\begingroup$ I will let know...I took a developmental biology course so i have some idea $\endgroup$
    – krushna
    Jan 4, 2014 at 10:07
  • $\begingroup$ it is not the maternal genome that regulates embryonic development.. the cytoplasmic factors in the oocyte which include RNAs, proteins and mitochondria, are responsible for the maternal effects.. $\endgroup$
    Jan 6, 2014 at 4:57
  • $\begingroup$ @WYSIWYG In this case the would contents of the sperm be in an hyper condensed condition and play no role in embryonic genome activation? $\endgroup$
    – user3800
    Jan 6, 2014 at 6:20

1 Answer 1


The pronuclei fuse and decondensation happens and now the cell is called a zygote. There is a stage called the midblastula transition (MBT), until which only the maternal products (cytoplasmic factors such as RNAs, proteins and ribosomes) are used. After MBT the zygote starts expressing its own genes from both the paternal and maternal alleles. However, certain genomic regions are imprinted which means that one of the alleles is epigenetically silenced. It can be either paternal or maternal.


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