Skip to main content
Ch. 5 - Chromosome Mapping in Eukaryotes

Chapter 5, Problem 10

Colored aleurone in the kernels of corn is due to the dominant allele R. The recessive allele r, when homozygous, produces colorless aleurone. The plant color (not the kernel color) is controlled by another gene with two alleles, Y and y. The dominant Y allele results in green color, whereas the homozygous presence of the recessive y allele causes the plant to appear yellow. In a testcross between a plant of unknown genotype and phenotype and a plant that is homozygous recessive for both traits, the following progeny were obtained: colored, green 88 colored, yellow 12 colorless, green 8 colorless, yellow 92 Explain how these results were obtained by determining the exact genotype and phenotype of the unknown plant, including the precise arrangement of the alleles on the homologs.

Verified Solution
Video duration:
1m
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Video transcript

Hello everyone and welcome to today's video. So recombination frequencies are helpful in figuring out the order of jeans on a specific chromosome. Suppose we have the following recombination frequencies we have the F G if 12.1% F G is 7.3% and E G is 19.4%. Which of the following gives the correct order of the genes E F G in the chromosome. Well, all we need to know to solve this question is that the higher the recombination frequency, the further apart These jeans are going to be in the chromosome. So if we look at our recombination frequencies that were given these genes, FG are going to be, are going to be the highest recombination frequency and 19.4%. This means that in the chromosome they're located the farthest apart. And the only gene that is left is going to be gene f which is going to be located in the middle between them. And that is going to be the order of the genes in the chromosome is going to be E then F, then G is going to be given by answer choice. I really hope this video helped you and I hope to see you on the next one
Related Practice
Textbook Question
What is the proposed basis for positive interference?
411
views
Textbook Question
What two essential criteria must be met in order to execute a successful mapping cross?
297
views
Textbook Question
The genes dumpy (dp), clot (cl), and apterous (ap) are linked on chromosome II of Drosophila. In a series of two-point mapping crosses, the following genetic distances were determined. What is the sequence of the three genes? dp–ap 42 dp–cl 3 ap–cl 39
512
views
Textbook Question
In the cross shown here, involving two linked genes, ebony (e) and claret (ca), in Drosophila, where crossing over does not occur in males, offspring were produced in a 2 + : 1 ca : 1 e phenotypic ratio: These genes are 30 units apart on chromosome III. What did crossing over in the female contribute to these phenotypes?

675
views
Textbook Question
In a series of two-point mapping crosses involving five genes located on chromosome II in Drosophila, the following recombinant (single-crossover) frequencies were observed: pr–adp 29% pr–vg 13 pr–c 21 pr–b 6 adp–b 35 adp–c 8 adp–vg. 16 vg–b. 19 vg–c 8 c–b. 27 Given that the adp gene is near the end of chromosome II (locus 83), construct a map of these genes.
794
views
Textbook Question
In a series of two-point mapping crosses involving five genes located on chromosome II in Drosophila, the following recombinant (single-crossover) frequencies were observed: pr–adp 29% pr–vg 13 pr–c 21 pr–b 6 adp–b 35 adp–c 8 adp–vg. 16 vg–b. 19 vg–c 8 c–b. 27 In another set of experiments, a sixth gene, d, was tested against b and pr: d–b 17% d–pr 23% Predict the results of two-point mapping between d and c, d and vg, and d and adp.
506
views