• Support PF! Buy your school textbooks, materials and every day products Here!

Can anyone help me with ny of these 4 genetics questions?

  • Biology
  • Thread starter stew
  • Start date
  • #1
1
0
1. The genes for mohogany eyes and ebony body are approximately 25 map units apart on chromosome III in Drosophila. Assume that a mahogany-eyed female was mated to an ebony-bodied male and the resulting F1 phenotypically wild type females were mated to mahogany, ebony males. Of 1000 offspring, what would be the expected phenotypes and in what numbers would they be expected?

2. Given that loci A and B in Drosophila are sex-linked and 20 map units apart, what phenotypic frequencies would you expect in male and female offspring resulting from the following crosses? (Assume A and B are dominant to a and b, respectively):
(a) AaBb(cis)female X ab/Y male
(b) AaBb(trans) X ab/Y male
(c) aabb female X AB/Y male

3. Assume that there are 12 map units between two loci in the mouse and that you are able to microscopically observe meiotic chromosomes in this organism. If you examined 200 primary oocytes, in how many would you expect to see a chiasma between the two loci mentioned above?
I got 2 for an answer. Is that correct?

4. Phenotypically wild F1 female Drosophila, whose mothers had light eyes(Lt) and fathers had straw(stw) bristles produced the following offspring when crossed to homozygous light-straw males:
phenotype: number:
light-straw 22
wild 18
light 990
straw 970
total: 2000
Compute the map distance between light and straw loci.
I got 1.1 mu for an answer. Is that correct?

Thanks in advance for any help.
 

Answers and Replies

  • #2
Moonbear
Staff Emeritus
Science Advisor
Gold Member
11,490
51
Keep in mind our rules require you to show your own efforts first. Tell us how you got the answers you got.
 

Related Threads for: Can anyone help me with ny of these 4 genetics questions?

  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
2
Views
3K
  • Last Post
Replies
6
Views
2K
Replies
1
Views
3K
Replies
6
Views
4K
Replies
5
Views
2K
  • Last Post
Replies
5
Views
3K
  • Last Post
Replies
2
Views
6K
Top