Name __________________________ BIO 2110 – Exam 2 31 October 2014 10 questions /10 points per question see last page for potentially useless formulae bonus question on back of cover pageName __________________________ Bonus question (2 pts). Below is an epistatic pathway for dorsoventral axis specification in Drosophila embryos. What is the medical relevance of this pathway? spätzle dorsal ⊣ cactus ⊣ pelle ⊣ toll ⊣ snake easter >>>>> one sentence answers only <<<<<<Name __________________________ 1. What type of mutation would more likely have a deleterious effect on gene function, a point mutation in codon 3, a two nucleotide deletion in codon 3 or a three nucleotide deletion in codon 3? Explain your answer.Name __________________________ 2. Below is shown a Punnett Square for a monohybrid cross. On this diagram, indicate where: i. sperm genotypes are represented ii. oocyte genotypes are represented iii. what frequencies would be expected for each of these genotypes iv. where genotypes of zygotes would be represented. If AA homozygotes had large ear and aa homozygotes had small ears, what additional information would you need to predict the frequencies of large and small eared individuals in the next generation? A aA!!!!aName __________________________ 3. The halosis (hal), bellum (bel), jajunium (jaj) and nox (nx) genes all are on chromosome 3 in Beatus pallentes. Based on the data shown below, what is the order of these genes on this chromosome? cross 1 hal bel nox hal bel nox HAL BEL NOX x hal bel nox hal bel nox 360 HAL BEL NOX 360 hal bel NOX 90 HAL BEL nox 90 hal BEL nox 40 HAL bel NOX 40 HAL bel nox 10 hal BEL NOX 10 cross 2 hal jaj nox hal jaj nox HAL JAJ NOX x hal jaj nox hal jaj nox 486 HAL JAJ NOX 486 hal jaj NOX 66 HAL JAJ nox 66 hal JAJ nox 6 HAL jaj NOX 6 HAL jaj nox 42 hal JAJ NOX 42Name __________________________ 4. In the following cross, indicate the frequencies you would expect the selected F2 phenotypes. Assume P0s are homozygous for all genes involved. What other assumption is need to calculate these expected frequencies? P0s hairy, blue nose, two fingers, red eyes, scabarous x hairless, noseless, one finger, green eyes, smooth ⇓ F1s hairy, red nose, one finger, red eyes, scabarous x hairy, red nose, one finger, red eyes, scabarous F2 phenotype expected frequency hairy, red nose, one finger, red eyes, scabarous ________ hairless, blue nose, two fingers, green eyes, smooth ________ hairy, noseless, one finger, green eyes, scabarous ________Name __________________________ 5. Wild-type hippogriffs have a single pair of wings. Recessive mutations in some genes result in wingless hippogriffs and recessive mutations in other genes result in hippogriffs with two pairs of wings (the biwinged phenotype). Based on the data presented below, construct an epistatic pathway for the regulation of wing development in hippogrffs. genotype phenotype nowings wingless wingsgone wingless sanswing wingless wingsome biwinged winger biwinged nowings; wingsome wingless nowings; winger biwinged wingsgone; wingsome biwinged wingsgone; winger biwinged sanswings; wingsome wingless sanswings; winger biwingedName __________________________ 6. Platypus eyes can be red or blue. They also can have round or slit pupils. Variation in each of these phenotypes is regulated by allelic variation at a single gene. These genes are linked. Based on the data presented below, determine the recombination distance between these genes. [P0s are homozygous] P0 red eye, round pupil x blue eye, slit pupil F1 blue eye, slit pupil x blue eye, slit pupil F2 blue eye, slit pupil 62 blue eye, round pupil 11 red eye, slit pupil 11 red eye, round pupil 16Name __________________________ 7. Genetic variation in the mtlc and lmb genes of blue-headed skinks affects head color and the presence or absence of legs. Based on the data presented below, are these genes linked. Justify your answer statistically. [P0s are homozygous] gene allele homozygous phenotype mtlc mtlc(+) head metallic blue mtlc(-) head slate blue lmb lmb(+) legs present lmb(-) legs absent generation head legs head legs P0 metallic present x slate Absent ⇓ F1 metallic present x metallic Present ⇓ F2 metallic present 923 metallic absent 277 slate present 277 slate absent 123Name __________________________ 8. The larry (la), curly (cu) and moe (mo) genes are on the same chromosome (see below). Based on the segregation data shown, how much, if any, crossover interference is present in this region of the genome? la cu mo x la cu mo LA CU MO la cu mo la cu mo 270 LA CU MO 270 la cu MO 80 LA CU mo 80 la CU mo 20 LA cu MO 20 LA cu mo 130 la CU MO 130 30 cM 20 cMlarrycurlymoeName __________________________ 9. When during meiosis: i. do homologous chromosomes pair ii. does recombination occur between homologous chromosomes iii. do homologous chromsomes disjoin iv. do sister chromatids separateName __________________________ 10. Observations from a dihybrid cross of two unlinked autosomal genes are shown below. [P0s are homozygous] i. what phenotypes are controlled by each of the two genes involved? ii. which phenotypes are dominant and recessive? iii. what frequencies would you expect for each of the F2 phenotypes? iv. why is a novel phenotype that is not seen in P0s observed in the F2s? P0 red eyes x eyeless ⬇" F1 red eyes x red eyes ⬇" F2 red eyes yellow eyes eyelessName __________________________Name __________________________ probability df 0.90 0.50 0.20 0.05 0.01 0.001 1 0.02 0.46 1.64 3.84 6.64 10.83 2 0.21 1.39 3.22 5.99 9.21 13.82 3 0.58 2.37 4.64 7.82 11.35 16.27 4 1.06 3.36 5.99 9.49 13.28 18.47 5 1.61 4.35 7.29 11.07 15.09 20.52 χ2 values Lod = Log10(odds) χ2 = Σ [(obs-exp)2/exp] p2 + 2pq + q2 = 1 p2 + q2 + r2 + 2pq + 2pr + 2qr = 1 df = n – 1 !!!!!! ¼ p2 !!!!!! p + q = 1 #classes = 2n