Lecture 8 Flashcards
XIST expression occurs on the:
Inactive X chromosome
For imprinted genes, selection of the active allele is random? Non random?both??
Non random
True or false
The inactive X chromosome in females is completely silenced
False
True or false
Imprinting is maintained in the primordial germ cells
False
The silenced X chromosome in females is commonly referred to as what
The Barr body
True or false
Angelman syndrome and Prader-Willi syndrome are imprinting disorders that map to a 2-Mb location at 15q 11-13
True
As a general rule, cytosine DNA methylation marks genes for…?
Silencing
The CG dinucleotide is often denoted as CpG where:
The P stands for a phosphodiester bond
The dinucleotide CG is underrepresented in the human genome because
methylcytosine is highly susceptible to spontaneous deamination, resulting in the TG dinucleotide.
When the allele choice is determined by its parent-of-origin, monoallelic gene expression is referred to as what?
imprinting.
True or false
Methylation patterns are erased during germ cell development and then re-established at the zygote stage
True
Monoallelic expression mechanism is due to what?
Altered chromatin structure in the gene promoter
Differential expression of an antisense RNA transcript
Blocking of an enhancer by an insulator
Which does not constitute a major epigenetic mechanism involved in mammalian X inactivation?
gene rearrangement
A CpG island refers to C lying next to G along a piece of DNA where p probably denotes
Phosphodiester bond
Inherited defects that are not due to alterations in the DNA sequence are referred to as:
Epigenetic
