Homework 4 Note this homework has an alternate due date and must be completed by the start of class on Tuesday February 10th You will use your responses on this assignment to help you with the group CER activity CASE INFORMATION Eastern chipmunks Tamias striatus are organisms 2n 38 Suppose you identify new mutations in three genes found in Eastern chipmunks The three genes and associated alleles are summarized in Table 1 below diploid Table 1 Three genes with corresponding phenotypes and alleles in Eastern chipmunks Tamias striatus Gene Phenotype Fur Pattern Cheek Pouch Size Tail Thickness Phenotype Dominant Allele Bold stripes B Large E Thick T Phenotype Recessive Allele Faint stripes b Small e Thin t Figure 1 Eastern chipmunk Tamias striatus silhouette Part 1 Predicting Genotypes Use the information in Table 1 to predict the genotypes of chipmunks 1 and 2 and their parents Chipmunk 1 has bold stripes large cheek pouches and a thin tail Chipmunk 2 is heterozygous for fur pattern and cheek pouch size and has a thin tail The maternal parents of both chipmunks have faint stripes small cheek pouches and thin tails The paternal parents of both chipmunks are homozygous dominant for fur pattern and cheek pouch size and thin tails Q1a What is Chipmunk 1 s genotype Q1b What is Chipmunk 2 s genotype Q1c What is the genotype for the maternal parent of both chipmunks Q1d What is the genotype for the paternal parent of both chipmunks Part 2 Independent Assortment unlinked traits We do not currently know if the three genes controlling fur pattern cheek pouch size and tail thickness are on the same or separate chromosomes For the questions in Part 2 assume that all three genes are unlinked and show independent assortment Q2a Draw chromosomes for chipmunk 1 in G1 and G2 pre and post replication Each chromosome should include a centromere and clearly labeled alleles Label homologous pairs and sister chromatids where appropriate Show which chromosomes were inherited from the mother and which from the father Q2b Draw chromosomes for chipmunk 1 in metaphase I of meiosis Construct drawings to show all possible unique alignments based on genotype Each chromosome should include a centromere and clearly labeled alleles Label homologous pairs and sister chromatids where appropriate Show which chromosomes were inherited from the mother and which from the father Q2c From each of your alignments from Q2b draw the resulting gametes for chipmunk 1 at the end of meiosis from that specific alignment Each chromosome should include a centromere and clearly labeled alleles Label homologous pairs and sister chromatids where appropriate Q2d Based on your results from Q2c what are all possible genotypes of the gametes of chipmunk 1 consider all unique alignments Q2e Cross chipmunk 1 with chipmunk 2 What is the phenotypic ratio of the offspring of this cross Show your work and be clear about which ratio corresponds to each phenotype Part 3 Dependent Assortment linked traits Some researchers suspect fur color and cheek pouch size may be linked on the same chromosome In this part of the activity explore what the chromosomes would look like during various stages of meiosis assuming that the genes for fur pattern and cheek pouch size are linked and will therefore assort dependently Assume that the gene for tail thickness is unlinked from the other two Q3a Draw chromosomes for chipmunk 1 in G1 and G2 pre and post replication Each chromosome should include a centromere and clearly labeled alleles Label homologous pairs and sister chromatids where appropriate Show which chromosomes were inherited from the mother and which from the father Q3b Draw chromosomes for chipmunk 1 in metaphase I of meiosis Construct drawings to show all possible alignments Each chromosome should include a centromere and clearly labeled alleles Label homologous pairs and sister chromatids where appropriate Show which chromosomes were inherited from the mother and which from the father Q3c Draw all possible gametes for chipmunk 1 at the end of meiosis Each chromosome should include a centromere and clearly labeled alleles Label homologous pairs and sister chromatids where appropriate Q3d Based on your chromosomes from Q3c what genotypes are possible in the gametes of chipmunk 1 Q3e Cross chipmunk 1 with chipmunk 2 What is the predicted phenotypic ratio of the offspring of this cross Show your work and be clear about which ratio corresponds to each phenotype