STP Genomics & Molecular Biology 3

Question 1

Epigenetics refers to changes in gene expression that are:

Accepted Answer

Heritable changes in gene activity not involving changes to the underlying DNA sequence

Answer

Caused by alterations in the primary DNA nucleotide sequence

Answer

Exclusively transmitted through the maternal germline only

Answer

Caused by somatic mutations accumulating during cell division

Question 2

In the clinical genomics laboratory, variant interpretation follows which internationally recognised classification system?

Accepted Answer

The ACMG/AMP five-tier variant classification (Pathogenic to Benign)

Answer

The WHO tumour grading classification (I–IV)

Answer

The ISCN chromosomal nomenclature tier system

Answer

The CAP/RCPA laboratory accreditation scoring scheme

Question 3

What is a microsatellite in the context of genomic analysis?

Accepted Answer

A short tandemly repeated sequence (1–6 bp repeat unit) distributed throughout the genome

Answer

A small non-coding RNA that regulates gene expression

Answer

A fluorescently labelled probe used in FISH analysis

Answer

A conserved regulatory element found in gene promoters

Question 4

Bioinformatics pipelines in clinical genomics typically include which sequence of steps?

Accepted Answer

Base calling → alignment to reference genome → variant calling → annotation and filtering

Answer

Library preparation → hybridisation capture → gel electrophoresis → Sanger confirmation

Answer

RNA extraction → cDNA synthesis → cloning → sequencing

Answer

Probe design → hybridisation → washing → fluorescent imaging only

Question 5

Loss of heterozygosity (LOH) in tumour genomics indicates:

Accepted Answer

Loss of one allele at a locus, often revealing a recessive mutation in the remaining allele

Answer

A gain of an additional chromosome copy in the tumour cell

Answer

Increased methylation silencing both alleles of a tumour suppressor gene

Answer

Translocation of a proto-oncogene next to a strong enhancer

Question 6

The term 'allele frequency' in a population genetics context describes:

Accepted Answer

The proportion of all alleles at a given locus in the population that are of a specific variant type

Answer

The rate at which new mutations arise per generation

Answer

The number of heterozygous carriers detected in a family pedigree

Answer

The fraction of mRNA transcripts carrying a particular splice variant

Question 7

Comparative genomic hybridisation (CGH) array analysis is used primarily to detect:

Accepted Answer

Genome-wide copy number gains and losses at sub-megabase resolution

Answer

Single nucleotide variants in cancer driver genes

Answer

Epigenetic methylation patterns across CpG islands

Answer

Structural chromosomal rearrangements such as reciprocal translocations