Concept explainers
Two pure
a. Based on the
b. How many additive alleles are required to explain the five
c. Using clearly defined allele symbols of your choice, give genotypes for the parental strains and the
d. If an
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Genetic Analysis: An Integrated Approach (3rd Edition)
- Two pure-breeding lines of petunia plants are crossed. Line 1 plants grow to a height of 54 cm, and Line 2 plants grow to a height of 18 cm. Petunia plant height is controlled by three genes, A, B and C. Line 1 has the genotype A₁A₁B₁B₁C₁C₁, and line 2 has the genotype A2A2B₂B₂C₂C₂. Assume that genotype alone determines plant height under ideal growth conditions and that the alleles of the three genes are additive. If the F1 plants are self crossed, what is the expected proportion of F2 plants with the genotype A₁A₁B₁B₁C₁C₁ 1/8 1/32 1/16 1/4 1/64arrow_forwardE. W. Lindstrom crossed two corn plants with green seedlings and obtained the following progeny: 3583 green seedlings, 853 virescentwhite seedlings, and 260 yellow seedlings . Q. Give the genotypes for the green, virescent-white, and yellow progeny.arrow_forwardYellow guinea pigs crossed with white ones always produce cream-colored offspring. Two cream guinea pigs, when crossed, produce yellow, cream, and white offspring in the ratio of 1 yellow : 2 cream : 1 white. What principle of genetics is involved in this cross? (1 point) 2. The shape of radishes may be long, round, or oval. The following results were obtained in the different possible crosses: a. long x oval gave ½ long and ½ oval b. oval x round gave ½ oval and ½ round c. long x round gave all oval d. oval x oval gave ¼ long, ½ oval, and ¼ round Explain these results. Hint: Show genotypes of each cross) (2 points). a. b. c. d. 3. In human blood types, what are the genotypes of the following parents? (2 points). Phenotypes of ParentsPhenotypes of OffspringGenotypes of parents ABABO A x AB½ 0½ 0_______ x _______ A x AB½ ¼¼0_______ x _______ A x A¾00¼_______ x _______ A x O½00½_______…arrow_forward
- Consider the following dihybrid testcross: B/b • E/e × b/b • e/e For the progeny from this testcross, determine the relative proportions (from 0% to 100%) of each genotype if the two genes: a) are linked (dominant alleles in cis conformation) with no crossing over: Be/be: be/be: BE/be: bE/be: b) assort independently. B/b; E/e: B/b; e/e: b/b; E/e: b/b; e/e: c) are linked (dominant alleles in cis conformation) and 20 map units apart. Be/be: be/be: BE/be: bE/be:arrow_forwardA cross was performed using Drosophila melanogaster involving a female known to be heterozygous for both ebony body and sepia eyes and a male known to be homozygous wild type male. The resulting progeny were allowed to mate with one another to produce the data set. Three repetitions of the experiment were conducted. The following data were produced from the crosses. Test these data to determine if they are significantly different from the expected phenotypic ratio. Use the 5% level of significance. Your answer should include the hypothesized cross in genotypes, the Chi-squared value, the critical value and whether you reject or do not reject for each experiment. Wild eye Wild body – 112, Wild eye Ebony body – 40, Sepia eye Wild body – 35, Sepia eye Ebony body – 11arrow_forwardA purple snow pea plant known to be hybrid for three linked genes (a, b, and d) is testcrossed. The progeny phenotypes and frequencies are: +a+ 86 b+d 56 +ad 78 b++ 49 +++ 12 bad 6 ba+ 515 ++d 460 a) Draw the chromosomes of the trihybrid and tester lined mentioned above. b) Give a map of the gene order with distance.arrow_forward
- A test cross between a plant of genotype PpSs and the tester white plant with wrinkled seed coat (ppss) gives the following numbers of progeny in four phenotypic types. 14:87:83:16 (purple flower + smooth seed coat: purple flower + wrinkled seed coat: white flower + smooth seed coat: white flower + wrinkled seed coat). a. What is the expected ratio of progeny phenotypes assuming independent assortment of alleles? b. Explain how ratios of progeny show that the two genes are linked. c. How many map units separate the purple and smooth genes? Show your calculations. d. What is the “parental” genotype of the heterozygous parent? (i.e. Which alleles of the P and S loci are present on each of the two chromosomes of the doubly heterozygous parent of this test cross?)arrow_forwardThree autosomal recessive mutations in yeast, all producing the same phenotype (m1, m2, and m3), are subjected to complementation analysis. Of the results shown below, which, if any, are alleles of one another? Predict the results of the cross that is not shown—that is, m2 * m3. Cross 1: m1 * m24 F1: all wild-type progeny Cross 2: m1 * m34 F1: all mutant progenyarrow_forwardA dihybrid testcross is made to determine if genes C and D are linked. The results are shown in the table. 1. The chi-square value is the sum for all progeny classes of (observed-expected)2/expected. Using the chi-square test for goodness of fit, calculate the chi-square value to test the null hypothesis that genes C and D are unlinked. What is the chi-square value? 2. Using the chi-square test for goodness of fit, how many degrees of freedom are in this data set? 3. Using table 5.2 find the most accurate range within which the p value falls. 4. What is a reasonable conclusion based on the chi-square analysis?arrow_forward
- In the tomato, yellow flowers (Y) is dominant to white flowers (y). A true-breeding yellow flowered strain is crossed with a true-breeding white flowered strain.A. If the F1 generation is self crossed, what will be the genotypes and phenotypes of the progeny and in what portions are they expected? B. If an F1 plant were crossed with a plant from true-breeding white flowered strain, what will be the genotypes and phenotypes of the progeny and in what portions are they expected?arrow_forwardAn individual with the genotype F/f • G/g • H/h is testcrossed. Among the progeny, the proportions of genotypes from this cross are shown in the following table: a) What gene is in the middle? Type you answer in this box: b) Calculate the genetic distances (in centimorgans, cM) between: genes g and f: genes f and h: genes g and h: c) What are the genotypes of the two parents? d) Calculate the interference and type your answer here:arrow_forwardIn tomatoes, dwarf (d) is recessive to tall (D) and opaque (light-green) leaves (op) are recessive to green leaves (Op). The loci that determine height and leaf color are linked and separated by a distance of 7 m.u. For each of the following crosses, determine the phenotypes and proportions of progeny produced.arrow_forward
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