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

Genetics recombination questions

  • Biology
  • Thread starter sonyab523
  • Start date
  • #1
12
0
Confused on 2 questions here


If a recombination frequency between two genes is 1.5%, what is the distance between the genes in map units on the linkage map?

a. Impossible to determine, because the interference is not known.
b. 1.5
c. 3
d. 0.75

Recombination frequencies

a. arise from completely random genetic exchange.
b. are the same for all genes.
c. decrease with distance.
d. are the same for cis and trans heterozygotes.


I thought it was b for the first part a for the second part and but I'm wrong. Can someone explain?
 
Last edited:

Answers and Replies

  • #2
12
0
Sorry forgot to add my explanation

b. Each % frequency of recombination equals one map unit between the genes. So 1.5% recombination frequency = 1.5 map units apart will result in 1.5% recombination

a. It can't be (b), because genes are all distances apart; it can't be (c), because frequencies increase with increasing distance; it can't be (d), because the distance between genes is the same whether the alleles are cis or trans loci. So I thought it was a.
 
  • #3
12
0
Help help please.
 
  • #4
493
2
I'm not absolutely sure, but I'd probably agree with your answers.
 
  • #5
12
0
I'm not absolutely sure, but I'd probably agree with your answers.
I thought I was right but when I entered it into the system I was wrong. I'm sure the first part is right and I thought the second part was right but I guess not.
 
  • #6
epenguin
Homework Helper
Gold Member
3,712
752
I would probably agree too. It is a strange way of examining to ask which of four statements is correct. It seems to me though I am a bit rusty, that you have to a little bit psych what some of the questions mean, if it's any consolation.
 
  • #7
12
0
Well that can't be right since it's marked wrong. Anyone think it's c for the second part?
 
  • #9
chemisttree
Science Advisor
Homework Helper
Gold Member
3,362
390
I was thinking D and C. D because as the loci become further apart (low recombination values) the probability of a second crossover increases and the recombination value is overestimated. The only value less than 1.5 is 0.75 (D). I don't know what is meant by "interference" in answer A but that could be correct as well.

Edit. you are right C can't be correct
 
  • #10
12
0
I finally found some material that helped. I got it right and the answer was D. Thanks guys for your help I really appreciate it.
 
  • #11
493
2
I've been talking about question 2.
For which one is the answer D? What did you arrive at for number 2?
The link I recommended explicitly states that trans and cis heterozygotes exhibit equal recombination frequencies.
 
  • #12
12
0
I've been talking about question 2.
For which one is the answer D? What did you arrive at for number 2?
The link I recommended explicitly states that trans and cis heterozygotes exhibit equal recombination frequencies.
D is the answer for the second question. So you were right.
 
  • #13
493
2
D is the answer for the second question. So you were right.
My apologies, I lost track of the question! Technically I wasn't right, the textbook was...:grumpy:
 

Related Threads on Genetics recombination questions

Replies
2
Views
4K
  • Last Post
Replies
0
Views
10K
Replies
2
Views
5K
  • Last Post
Replies
1
Views
565
  • Last Post
Replies
0
Views
2K
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
0
Views
2K
Replies
6
Views
4K
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
2
Views
3K
Top