Genetics MCQs 2


Question #1: A diploid cell contains the alleles R and r on one pair of homologous chromosomes and the alleles S and s on another pair of homologous chromosomes. How many combinations of these alleles could appear in the gametes after meiosis?

Question #2: Which statements concerning inbreeding are correct? 1. Inbreeding increases the chance of individuals arising that are double recessive for an unfavourable allele 2. Inbreeding results in loss of genetic diversity amongst individuals of a domestic variety 3. Inbreeding depression results from hybridisation between unrelated species 4. Inbreeding promotes the retention of favourable characteristics 5. Inbreeding increases the chance of unfavourable characteristics

Question #3: In the fruit fly Drosophila melanogaster, the white-eye allele is X-linked and recessive. What would be the outcome of a cross between a white-eyed female and a red-eyed male?

Question #4: Three independently-assorting genes in humans: A, B and C. What is the probability that a mother of genotype AaBBCc and a father of genotype AAbbCc will produce a child of genotype AABbcc?

Question #5: Which of the following combinations of statements about an autosomal dominant gene is correct? 1. It will exhibit a phenotype in heterozygotes 2. It will be transmitted to all progeny from a homozygous parent 3. It cannot be carried on the Y chromosome 4. It cannot be transmitted from males to males

Question #6: Dihybrid plants of Capsella were cross-pollinated, 94% of the progeny possessed triangular seed capsules and 6% oval seed capsules. What is the genotype of a plant with oval seed capsules?

Question #7: The main advantage of sexual reproduction compared with asexual reproduction is that it enables:

Question #8: What is the probability for exactly three children to have a dominant phenotype in a family with four children of heterozygous parents (Aa x Aa)?

Question #9: A person with PKU marries a person with AKU. What are the expected phenotypes for their children?

Question #10: If in a population the frequency of the ‘AA’ genotype is 0.25 and the frequency of the ‘Aa’ genotype is 0.45, in Hardy-Weinberg equilibrium, the frequency of matings between the ‘aa’ & ‘aa’ genotypes will be:

Also read: Linkage and Crossing overMutationDNA ReplicationTranscriptionRNA processing MnemonicTypes of RNA (ribonucleic acid)Protein Synthesis (Translation)Protein Synthesis MnemonicCell Cycle MnemonicPedigree Analysis.


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