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24 Apr 2019

Recombination events are proportional to the distance between two genes. Therefore, if two genes (A and B) are further apart, the frequency of recombination between them will . But, if cold spots exist around the genes A and B, the frequnecy of recombination between them will .

A.
Increase, stay the same

B.
stay the same, decrease

C.
increase, decrease

D.
decrease, increase

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Deanna HettingerLv2

27 Apr 2019

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Related questions

ANSWER ALL the PARTS you can

PART1 Alleles are considered linked if recombination is less than 50% in:

a) a Px P Fl cross

b) an F1 x F1F2 cross

c) an F2 x F2F3 cross

d) an Fl x homozygous recessive cross

e) any F2 progeny x homozygous recessive cross 1.

PART2 If two loci A/a B/b are 9 map units apart, and an Ab/aB individual is testcrossed,

a) There will be 9% AB individuals

b)There will be 91% Ab individuals

c) There will be 4.5% ab individuals

d) There will be 91% recombination individuals

If two genes a and b show 50% recombination genes a and c show 35% recombination, and genes b and show 32% recombination, then

a) Genes a and b are on the same chromosome, and 50 m.u. apart

b) Genes a and b are on different chromosomes

c)Genes a and b are on the same chromosome, and 67 map units apart

d) One cannot tell if genes a and b are on the same or different chromosomes from given data.

PART4 If two genes a and b are 8.3 m.u. a part, one expects to find

a) 8.3% recombinant gametes from a double heterozygous parent

b) 91.7% recombinant gametes from a double heterozygous parent

c) A chiasma between the a and b loci in 8.3% of the meiosis

d) A chiasma between the a and b loci in 91.7% of the meiosis.

PART5 Map distances are most accurate when genes are closely linked because as genes become further apart,

a) They always show independent assortment

b)The chance of multiple crossovers increases

c) They no longer recombine

d) There is chiasma interference

PART6 In a three-point testcross, the most frequent classes of progeny were ABc and abC. The less frequent classes of progeny were AbC and aBc. Which gene is in the middle?

a) Aa

b) B/b

c)C/c

d) It is not possible to tell from just these data

PART7 In a three-point testcross with 100 progeny, there were 16 single crossovers between genes A and B, 29 single crossovers between genes B and C, and 4 double crossovers. The correct gene order was determined to be A-B-C. What is the map distance between A and B?

a) 20%

b) 0.2 m.u

c) 20 m.u.

d) 16 m.u.

e) 29 m.u.

f) 16%

4. Consider the imaginary linked genes A and B in Neurospora.

35% of meioses display no crossover.

35% have one crossover in the region between the genes.

30% have two crossovers in the region between the genes.

a. What is the predicted recombination frequency? Show your work, including the formula used to calculate the recombination frequency.

Answer:

b. Which tetrad type numbers in the progeny should be compared to determine if genes in Neurospora are linked? Explain why.

Answer:

Can you please help me out?

yellowleopard653

1) An individual is heterozygous for 3 genes (A/a B/b and C/c). He is crossed to an individual that is homozygous recessive for the same 3 genes (a/a b/b and c/c). The following offspring were seen. Which of the following phenotypes represent a double crossover event? (Hint - are you seeing all of the phenotypes in the next generation that you expected to see?) Select all that apply.

Phenotype	Number
+++	154
+b+	322
a+c	318
abc	148
++c	76
ab+	82

2) Use the same information in the question above. What is the gene order?

		The gene order is B-C-A
		The gene order is A-B-C
		The gene order is B-A-C

3) Using the same information as in the previous problem, What is the recombination frequency between each gene pair? Round your answer to 2 decimal places. For example, report 12.2345% as 0.12.

recombination frequency between A/B =

recombination frequency between A/C =

recombination frequency between B/C =

******According to the hint, we don't see two phenotypes that we are expecting which are +bc, and a++. Are those the ones that represent double crossovers, and if so, how do we calculate the recombination frequency between each gene? Would very much appreciate some help.