STP Genomics & Molecular Biology 2

Question 1

A genome-wide association study (GWAS) is designed primarily to:

Accepted Answer

Identify statistical associations between common genetic variants and specific traits or diseases

Answer

GWAS scans the genomes of large populations to identify SNPs or other variants that are statistically associated with a phenotype or disease, without a prior hypothesis about specific genes.

Question 2

Copy number variations (CNVs) refer to:

Accepted Answer

Segments of DNA ≥1 kb present in a variable number of copies relative to a reference genome

Answer

CNVs are structural variants typically ≥1 kb in size where the number of copies of a genomic segment differs between individuals, contributing to phenotypic diversity and disease susceptibility.

Question 3

RNA sequencing (RNA-seq) is used in clinical and research genomics to:

Accepted Answer

Quantify and characterise the transcriptome, including expression levels and splicing variants

Answer

RNA-seq converts the transcriptome to cDNA and sequences it using NGS, providing quantitative gene expression data and revealing transcript isoforms and fusion genes.

Question 4

CRISPR-Cas9 gene editing works by:

Accepted Answer

Guided RNA directing the Cas9 endonuclease to a specific genomic sequence where it introduces a double-strand break

Answer

A single guide RNA (sgRNA) complementary to the target sequence directs Cas9 to that locus where it creates a site-specific double-strand break, triggering repair pathways that can be exploited for editing.

Question 5

In genomic medicine, a 'variant of uncertain significance' (VUS) means that:

Accepted Answer

Insufficient evidence exists to classify the variant as pathogenic or benign

Answer

VUS designates variants where current evidence is insufficient to determine pathogenicity, requiring follow-up studies, familial segregation analysis, or functional data before clinical action is taken.

(STP) Scientist Training Programme Practice Test

(STP) Scientist Training Programme Practice Test

STP Genomics & Molecular Biology 2