1. When determining the relative genetic distance between twogenes, why is dihybrid back-cross preferable over traditionaldihybrid cross?
A. 9:3:3:1 phenotypic ratio is easier to work with than 1:1:1:1ratio.
B. Genotypes of the offspring can be determined based on theirphenotype.
C. If the genes are independently assorted, the dihybridback-cross would result in only 2 genotypes in the F1generation.
D. B and C
1. When determining the relative genetic distance between twogenes, why is dihybrid back-cross preferable over traditionaldihybrid cross?
A. 9:3:3:1 phenotypic ratio is easier to work with than 1:1:1:1ratio. | |
B. Genotypes of the offspring can be determined based on theirphenotype. |
C. If the genes are independently assorted, the dihybridback-cross would result in only 2 genotypes in the F1generation. | |
D. B and C |
Related textbook solutions
Related questions
Which of these statements is incorrect?
Syntenic genes are located on the same chromosome. |
Independent assortment results in recombinant chromosomes. |
You can reliably predict the relative genetic distance fromgenesâ physical distance on a chromosome. |
Linked genes are always syntenic. |
What is the relative genetic distance between two linked genesif the recombination frequency is 0.49?
0.49 cM |
4.9 cM |
49 cM |
490 cM |
What statement best explains the distortion in Mendelian ratiosobserved by Bateson & Punnett in 1905? (Reminder: they found anoverrepresentation of F2 offspring showing both dominant orrecessive phenotypes, and an underrepresentation of offspringdisplaying one dominant and one recessive phenotype)
| Human error: they should have been more careful about theirexperimental setup. |
| Gene linkage: Genes for flower color and pollen shape arephysically close on the same chromosome, leading to a breakdown inthe independent assortment of the alleles for these traits. |
| Chromosome crossover: Homologous recombination of twochromatids during meiosis caused the alleles to shuffle, resultingin a breakdown of the independent assortment of the alleles forthose genes. |
Random variation: No two situations are alike. In finitepopulations, you are going to get some variation across a mean. |
When determining the relative genetic distance between twogenes, why is dihybrid back-cross preferable over traditionaldihybrid cross?
| 9:3:3:1 phenotypic ratio is easier to work with than 1:1:1:1ratio. |
| Genotypes of the offspring can be determined based on theirphenotype. |
If the genes are independently assorted, the dihybrid back-crosswould result in only 2 genotypes in the F1 generation. |
B and C |
Why do we map genes?
| To understand how genes interact with each other |
| Comparative genomics analysis |
| To determine the genotype of an organism |
| All of the above |
In rats, several independently assorting autosomal genes affectcoat color. Gene A controls the distribution of yellowpigment in hair, and gene B causes black pigmentation. Thetwo genes interact as follows: AâBâ (gray), Aâbb(yellow), aaBâ (black), and aabb (cream). Thesegenotypes are only expressed in the presence of the dominant alleleof a third gene, C; rats with genotype cc arealbino.
a. Deduce the genotype of each albino mice, to the extent that ispossible, in the following table. Explain your answers.
True-breeding parents | F1 | F2 offspring |
Gray x albino-1 | All gray | 3/4 gray : 1/4 albino |
Gray x albino-2 | All gray | 9/16 gray : 3/16 yellow : 4/16 albino |
Part a. |
| Genotype of albino-1 parent is ⦠Explanation: |
| Genotype of albino-2 parent is ⦠Explanation: |
b. Deduce the genotype and phenotype of each parent in the followingtable. Explain your answers.
Parents | Numbers of offspring |
Cross 1 | 135 gray, 83 albino, 47 yellow, 44 black, 16 cream |
Cross 2 | 103 albino, 74 black, 25 cream |
Part b. | Parental phenotypes | Parental genotypes |
Cross 1 | x | x |
Explanation: | ||
Part b. | Parental phenotypes | Parental genotypes |
Cross 2 | x | x |
Explanation: | ||
c. A gray-colored rat ismated with one that is yellow. The offspring include an albino ratand a cream-colored rat. Diagram this cross. Be sure to include thePunnett square and the phenotypic ratio in the offspring.
Part c. |
| Cross is ⦠x Explanation: |
Punnett Square
Fill the punnet sq | ||||
Thank you
