Question

Could you please provide the best answer for following MCQs. Thank you.

Question 1

The imprinting control region is best defined as

		a promoter that regulates the expression of MeCP2
		a sequence that can be methylated or unmethylated to control the expression of one or more genes by regulating promoter-enhancer interactions
		a sequence that when unmethylated can bind RNA polymerase II to induce promoter activation
		an enhancer that is inhibited when methylated

Question 2

Imprinting is best described as

		a fixed pattern of gender-specific activation and repression of gene expression that is critical for normal development
		a fixed pattern of gender-specific repression of gene expression that is critical for normal development
		a fixed pattern of gender-specific activation of gene expression that is critical for normal development
		random repression and activation of gene expression of one copy of a gene that is critical for normal development

Question 3

The most common type of DNA methylation is found on

		the cytosine base of the sequence 5'-GC-3'
		the guanine base of the sequence 5'-GC-3'
		the cytosine base of the sequence 5'-CG-3'
		the guanine base of the sequence 5'-CG-3'

Question 4

In somatic cells

		patterns of methylation at imprinted loci is different between males and females
		patterns of methylation at imprinted loci is the same for males and females and only differs between the maternal and paternal chromsomes in a cell
		methylation of imprinted loci is essentially random
		imprinted loci on the maternal chromosome are always repressed Question 5 The UK Biobank was used to generate a genome-wide polygenic risk score for coronary artery disease. The number of alleles used to calculate this score was: less than 60 approximately 6000 650,000 more than 6 million

Answer 1

1. C

Mammalian genomes include DNA segments that are imprinted (CpG-methylated) only on one of the two parental chromosomes,. leading to parent-of-origin-specific gene expression. The process is regulated by ImprintingControl Regions (ICRs)

2.B

Genomic imprinting is an epigenetic developmental process by which around 100 imprinted genes are monoallelically expressed in a parent-of-origin–specific manner, so that the paternal and maternal alleles are differentially expressed.X-chromosome inactivation

3.C

The most widely characterized DNA methylation process is the covalent addition of the methyl group at the 5-carbon of the cytosine ring resulting in 5-methylcytosine(5-mC), also informally known as the “fifth base” of DNA. These methyl groups project into the major groove of DNA and inhibit transcription.

4. B

somatic cells maintain monoallelic expression of imprinted genes

5.B