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Q.) A geneticist is mapping the location of three markers relative to a disease

ID: 253801 • Letter: Q

Question

Q.) A geneticist is mapping the location of three markers relative to a disease causing genetic variant. Her results are shown below. Based on the results of the mapping, answer the following questions.

Marker

Recombination fraction relative to disease gene

X

0.3

Y

0.5

Z

0.1

a.) Which marker is closest to the disease-causing genetic variant? Support your answer. (2)

b.) Which marker is not linked to the disease-causing variant? Support your answer. (2)

c.) If the geneticist scored 200 chromosomes for recombination, how many recombinants did she observe for each marker? (2)

Marker

Recombination fraction relative to disease gene

X

0.3

Y

0.5

Z

0.1

Explanation / Answer

The recombinantion freequency or fraction indicates the distnace between gene. If the RF is high, which indicates that more distance. If the RF is equals or great than 0.5 which indicates that those two are segregated independently.

so,the answers are
a.) Which marker is closest to the disease-causing genetic variant? Support your answer. The answer is Z, because of its low RF i.e. 0.1 indicates that it is very close to gene.

b.) Which marker is not linked to the disease-causing variant? Support your answer.
The answer is Y, because the RF value here is 0.5, it indicates that the independent assrotment.

c) The answers are

Marker

Recombination fraction relative to disease gene

Population

Freequency (RF*population)

X

0.3

200

60

Y

0.5

200

100

Z

0.1

200

20

Marker

Recombination fraction relative to disease gene

Population

Freequency (RF*population)

X

0.3

200

60

Y

0.5

200

100

Z

0.1

200

20