7. One of Mendel’s crosses is described in Figure 4.10 in Lewis. a. List the F2

Question

7. One of Mendel’s crosses is described in Figure 4.10 in Lewis.

a. List the F2 genotypes and their proportions from Mendel’s dihybrid cross shown in Figure 4.10.

b. List the four types of gametes and their proportions (in percent) that resulted in the F2 offspring, and classify them as parental or recombinant.

c. List the four types of gametes and their proportions (in percent) if these genes had been on the same chromosome, 20 map units apart.

d. List the F2 genotypes and determine their proportions (in percent) according to the linkage described in part c. (6 marks)

8. A woman is heterozygous for three linked autosomal genes: GgHhMm. Her husband is homozygous recessive for each of the genes. They have eight children with the following genotypes: Three are GghhMm. Two are ggHhmm. One is GgHhmm. One is Gghhmm. One is gghhmm.

a. What is the most likely combination of alleles on each of the mother’s chromosomes? Explain.

b. List the genotypes of the recombinant children above. For each of these children, determine the location of the required crossover(s) in the mother’s oocyte to create their recombinant chromosome by identifying the two genes between which the crossover(s) occurred.

c. List the other possible recombinant genotypes that have not appeared in the offspring. (8 marks) A mother is heterozygous for an over-expressed plastin allele on her X chromosome, thus has longer than normal axons. She is also heterozygous for the SMN1 gene on chromosome

5. Her children’s father is normal for plastin and has normal length axons. He too is heterozygous for the SMN1 gene. Both genes influence spinal muscular atrophy type 1 (SMA1); two abnormal copies of the SMN1 gene are required to cause spinal muscular atrophy, but their effect is prevented by high expression of the plastin gene (Lewis 92).

a. Give the genotypes of the mother and the father; provide a legend for your symbols. For each gene, explain why the abnormal alleles are dominant or recessive. (4 marks)

b. List all the possible genotypes and proportions of their offspring for the plastin gene. (1 mark)

c. List all the possible genotypes and proportions of their offspring for the SMN1 gene. (1 mark)

d. Showing your work, determine the probability that this couple will have a daughter with SMA. (2 marks)

e. Showing your work, determine the probability that this couple will have a son with SMA. (2 marks)

10. The pedigree in Figure 5.9 in Lewis is for a mitochondrial gene. If it was for an X-linked gene, can you determine whether or not it is dominant or recessive? Why or why not? Make sure to use examples from the pedigree to support your answer. (5 marks)

11. In the following pedigrees, the disorders or traits presented follow simple patterns of Mendelian inheritance. For each pedigree, determine the most probable mode of inheritance of the trait, stating whether the trait is due to an autosomal or X-linked gene, and whether it is due to a dominant or recessive allele. Indicate and explain the evidence supporting your choice of pattern, and note evidence that does not support or conclusively eliminates the other patterns. Provide specific examples to defend your statements. Then, providing a legend for your symbols, assign genotypes to the specified individuals. (20 marks)

Pedigree A Provide genotypes for individuals I-4, II-2, III-12, and IV-2. Pedigree B Provide genotypes for individuals I-2, II-4, III-2, and IV-8.

12. Choose a current newspaper article (no older than two years before the start of your course contract) that describes a genetic study.* The article cannot be from a medical/health type of information source (such as Science Daily), or from a scientific publication. Summarize the information presented in the article in paragraph form by addressing the points below. (If you cannot address all or nearly all of these points, choose another article.) Include any other information relevant to your studies in this course, as provided in the article. (20 marks) · describe the phenotype of the trait.

· describe the genetic basis of the trait, identifying known genes, other genes involved, and any contributing environmental factors (or other information provided) that are relevant to expression of the trait.

· name the mode of inheritance if it is given or if you can deduce it.

· describe the particular type of mutation, as applicable.

· describe the related protein and its normal and mutant effects.

· identify any genetic technologies used in the study.

· does the author make any errors in use of terminology? Include a copy of the article (original, copy, or pdf attachment) with your assignment and provide a complete reference.

QUESTION 7 Seed form Seed color Pod fom Pod colo Flower position Seed coat color Stem length QUES Round (R)Yelow (Y Inflated (V) Green (G) Axial (F) (along stemgray-brown (A) Gray or Tall ?) Restricted (v) Terminal? (on top) Wrinkled (r) Green (y) Yellow (g) White (a) Short () Figure 4.1 Traits Mendel studied. Gregor Mendel studied the transmission of seven traits in the pea plant. Each trait has two easily distinguished expressions, or phenotypes. QUESTION 11g.A 10 11 113 IV 2 34 Pedigree A Provide genotypes for individuals I-4, I1-2, II1-12, and IV-2. Pedigree B 10 IV Pedigree B Provide genotypes for individuals I-2, 11-4, IlI-2, and IV-8.

Explanation / Answer

7.a: Round Yellow (RRYY), Round green (RRgg), Wrinkled Yellow (rrYY), Wrinkled Green (rrgg)

Proportion: 9:3:3:1 respectively.

b: Four types of F2 gametes: RY (Parental), Ry (Recombinant), rY (Recombinant), ry (Parental)

11.Pedigree A: I - 4: Aa(Dominant), II - 2: aa(Recessive) , III - 12: AA(Dominant), IV - 2: aa(Recessive) ( A = Dominant, a = Recessive)

Pedigree B: I - 2: Aa, II - 4: Aa, III - 2: Aa, IV - 8: aa

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