Question

7. Tra diploid organism has the genotype AABh, what% of its gametes would you expect to have the genotype A (assume that A/a locus and B/blocus are found on different chromosomes)? a) 1598 b) 2596 c) 5096 d) 7546 8. Phenylketonuria is an inherited human genetic disorder resulting from a mutation to the PAH gene. Individuals with mutant forms of the PAW gene exhibit leaming deficits, abnormal skin pigmentation, as well as heart problems. This is an example of: a) pleiotropy b) a polygenic trait c) incomplete dominance d) codominance e) epigenetic inheritance 9. A homozygous female (L.MLM) produces red blood cells with the "Mtype" glycoproteins. A homozygous male (UML) produces red blood cells with the "Ntype" glycoprotein. The give birth to 6 children: 3 females and 3 males. Each of their offspring (LL) have red blood cells with M and N type glycoproteins. This is an example of a) pleiotropy b) a polygenic trait c) incomplete dominance d) codominance e) epigenetic inheritance 10. Let R red and white. A female fruit fly with red eyes (X®X®) mates with a male fruit fly with white eyes (XY). Their male offspring a) are heterozygous b) all have white eyes c) have a 1:1 white eye: red eye ratio d) are hemizygous 11. In flies, blue eyes (B) is dominant to red eyes (b). You have a male and female fly, each has blue eyes but neither are true-breeding. The offspring of their cross follow a 3:1 ratio blue red and there are no differences between sexes. What type of inheritance patter does this describe? a) X-linked b) Y-linked c) autosomal d) epistasis

Answer 1

Question 7

Answer: The diploid organism with the genotype AABb, will produce AB and Ab gametes based on independent assortment. Hence, 50% of gametes is expected to have genotype AB. Hence, the correct answer is C and other answers are incorrect.

Question 8:

Answer: Phenylketonuria is an example of pleiotropy because mutation in the single PAH gene causes multiple phenotypes such as learning deficits, skin pigmentation and heart problem. Hence, the correct answer is option A.

Question 9:

Answer: The offsprings have a genotype of L^ML^N and their red blood cells have both M and N type glycoproteins. The presence of M type allele does not mask the effect of N type allele and vice versa. Hence, this is an example of codominance (neither allele mask the effect of the other allele) and the correct answer is option D. Pleiotropy is a condition where mutation in one gene leads to multiple phenotypes. As the offsprings doe not have multiple phenotypes, Option A is incorrect. Polygenic trait is a trait where single phenotype is influenced by two or more genes. In Incomplete dominance, neither allele is dominant. Epigenetic inheritance involves the transmission of epigenetic markers (phenotypic changes without change in the DNA sequence) from parents to offsprings. The offsprings did not show Polygenic trait, epigenetic inheritance and Incomplete dominance. Hence, option B, C, E are incorrect.