Biology 1002B Lecture Notes - Lecture 15: Mutation, Chromatin, Nucleosome
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Lecture 15: Identical Twins or Not
Monday, March 04, 2013
Identical twins or not
Xist (X inactive specific transcript) RNA binds along the inactive X chromosomes, silencing
The genes become in inaccessible to transcription machinery by Xist RNA coating the
chromosomes and making them inactive (stable throughout the life)
This is an epigenetic mechanism
What is different about identical twins?
Make different gametes
Different gene expression
Random X chromosome inactivation creates genetic mosaics in females
All of the decedents of the original cell, maintain the same X-chromosome inactivation
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