Eukaryotic gene families MCQs With Answer

Eukaryotic gene families MCQs With Answer

This quiz collection is designed for M.Pharm students to deepen understanding of eukaryotic gene families and their relevance to pharmacology and bioinformatics. The questions cover origin and classification of gene families, mechanisms such as duplication, divergence, gene conversion and pseudogenization, and examples important in drug response (e.g., cytochrome P450 and CYP2D6). You will also practice interpreting orthology/paralogy, domain architecture, HMM-based family detection, and phylogenetic reconciliation methods. Each MCQ includes plausible distractors and a clear correct answer to aid exam preparation and application to pharmacogenomics, drug metabolism, and computational analysis of gene families.

Q1. Which statement best defines a eukaryotic gene family?

• A group of genes that evolved from a common ancestral gene by duplication and share sequence similarity and related functions
• A set of genes that are expressed only in the same tissue
• Genes that are always located adjacent to each other on a chromosome
• A collection of unrelated genes involved in the same biochemical pathway

Correct Answer: A group of genes that evolved from a common ancestral gene by duplication and share sequence similarity and related functions

Q2. In gene family terminology, which describes paralogs?

• Genes in different species that evolved from a common ancestral gene through speciation
• Genes related by duplication within the same genome
• Nonfunctional copies of genes produced by retrotransposition
• Genes that code for proteins with identical sequences across species

Correct Answer: Genes related by duplication within the same genome

Q3. Which two major organizational types describe multigene families in eukaryotes?

• Tandemly repeated clusters and dispersed gene families located on different chromosomes
• Single-exon and multi-exon families only
• Orthologous and paralogous families exclusively
• Housekeeping-only and tissue-specific-only families

Correct Answer: Tandemly repeated clusters and dispersed gene families located on different chromosomes

Q4. What is the primary molecular mechanism that generates new members of a gene family?

• Gene duplication (including unequal crossing over and whole-genome duplication)
• Alternative splicing of a single gene
• Point mutations converting one gene into another functional gene
• RNA editing creating new genes

Correct Answer: Gene duplication (including unequal crossing over and whole-genome duplication)

Q5. The globin genes (alpha and beta clusters) are a classic example of which evolutionary process?

• Evolution of a multigene family by duplication followed by functional divergence
• Convergent evolution of unrelated gene sequences
• Horizontal gene transfer between species
• Recent single-nucleotide polymorphism-driven diversification

Correct Answer: Evolution of a multigene family by duplication followed by functional divergence

Q6. Which characteristic is most associated with Hox gene clusters in animals?

• Homeobox-containing transcription factors arranged in clusters showing spatial and temporal colinearity
• Rapidly evolving secreted peptides with no genomic clustering
• Single-copy metabolic enzymes encoded across multiple chromosomes
• Genes produced exclusively by retrotransposition

Correct Answer: Homeobox-containing transcription factors arranged in clusters showing spatial and temporal colinearity

Q7. Antibody diversity in vertebrates is primarily generated by which gene-family-related mechanism?

• Somatic V(D)J recombination of immunoglobulin gene segments
• Whole-genome duplication producing multiple antibody genes
• Alternative promoter usage of a single immunoglobulin gene
• Horizontal acquisition of bacterial antibody genes

Correct Answer: Somatic V(D)J recombination of immunoglobulin gene segments

Q8. Pseudogenes in gene families commonly arise by which processes?

• Gene duplication followed by disabling mutations or retrotransposition producing nonfunctional copies
• Immediate production of fully functional paralogs after duplication
• Horizontal transfer that results in increased function
• Alternative splicing that creates long noncoding RNAs only

Correct Answer: Gene duplication followed by disabling mutations or retrotransposition producing nonfunctional copies

Q9. Which gene family plays a central role in phase I drug metabolism and is highly relevant to pharmacogenomics?

• Cytochrome P450 (CYP) gene family
• Hemoglobin gene family
• Histone gene family
• Ribosomal RNA gene family

Correct Answer: Cytochrome P450 (CYP) gene family

Q10. Which database is specialized for identifying and annotating protein families and conserved domains?

• Pfam, a database of protein families represented by HMMs
• GenBank, which stores raw sequence reads only
• PubChem, which catalogs small molecules but not protein domains
• ClinicalTrials.gov, which lists human trials

Correct Answer: Pfam, a database of protein families represented by HMMs

Q11. Hidden Markov Models (HMMs) are most useful in bioinformatics for:

• Detecting remote homologs and conserved domains characteristic of protein families
• Predicting three-dimensional protein structures with atomic resolution
• Designing small-molecule drugs by docking simulations
• Measuring gene expression by qPCR

Correct Answer: Detecting remote homologs and conserved domains characteristic of protein families

Q12. A commonly used computational approach to identify putative orthologs between two genomes is:

• Reciprocal best BLAST hit (RBH) between proteomes
• Comparing GC content of genes only
• Aligning promoter sequences exclusively
• Counting intron numbers regardless of sequence

Correct Answer: Reciprocal best BLAST hit (RBH) between proteomes

Q13. Gene conversion within a gene family typically results in which outcome?

• Nonreciprocal transfer of sequence information that homogenizes paralog sequences
• Increased mutation rate leading to rapid divergence of family members
• Immediate loss of all paralogs from the genome
• Creation of entirely novel protein domains de novo

Correct Answer: Nonreciprocal transfer of sequence information that homogenizes paralog sequences

Q14. Domain shuffling contributes to gene family diversity by:

• Combining pre-existing protein domains into new architectures that can create novel functions
• Eliminating domains to produce only single-domain proteins
• Duplicating entire genomes without changing domain composition
• Restricting proteins to conserved catalytic motifs only

Correct Answer: Combining pre-existing protein domains into new architectures that can create novel functions

Q15. Olfactory receptor genes in mammals illustrate which properties of large gene families?

• Massive expansion by duplication, large numbers of pseudogenes, and lineage-specific variation
• Strict conservation as single-copy genes across all vertebrates
• Exclusive localization to mitochondrial DNA
• Function only as transcription factors with homeobox domains

Correct Answer: Massive expansion by duplication, large numbers of pseudogenes, and lineage-specific variation

Q16. Which gene-family-related genetic variation directly alters drug-metabolizing capacity and clinical response?

• Copy number variation of CYP2D6 leading to poor, normal, or ultrarapid metabolizer phenotypes
• Synonymous SNPs in actin genes that never affect protein levels
• Variation in ribosomal RNA gene counts that only affects blood type
• Presence of Hox clusters that determine limb patterning but not drug response

Correct Answer: Copy number variation of CYP2D6 leading to poor, normal, or ultrarapid metabolizer phenotypes

Q17. The classical Cys2His2 zinc finger transcription factor family is defined by:

• A conserved Cys2–His2 motif that coordinates a zinc ion and mediates sequence-specific DNA binding
• Glycosylation sites that anchor proteins in the membrane
• Large transmembrane helices characteristic of GPCRs
• Ribosomal binding regions that control translation

Correct Answer: A conserved Cys2–His2 motif that coordinates a zinc ion and mediates sequence-specific DNA binding

Q18. How does alternative splicing expand the functional repertoire within a gene family?

• By producing multiple protein isoforms from a single gene, increasing functional diversity without gene duplication
• By creating permanent genomic duplicates of the spliced isoforms
• By converting exons into introns across the family
• By eliminating all pseudogenes from the genome

Correct Answer: By producing multiple protein isoforms from a single gene, increasing functional diversity without gene duplication

Q19. After gene duplication, neofunctionalization refers to:

• One copy acquiring a novel function while the other retains the ancestral role
• Both copies immediately becoming pseudogenes
• Both copies always remaining completely redundant forever
• Loss of both copies from the genome due to selection

Correct Answer: One copy acquiring a novel function while the other retains the ancestral role

Q20. To distinguish duplication events from speciation in gene family evolution, researchers typically use which approach?

• Gene tree–species tree reconciliation, comparing gene phylogeny with the species phylogeny
• Measuring transcript half-life only
• Counting tandem repeats without sequence comparison
• Examining only the tertiary structure of proteins without phylogenetics

Correct Answer: Gene tree–species tree reconciliation, comparing gene phylogeny with the species phylogeny

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