A What map unit (Centimorgan) is adopted in the construction of genetic maps?

Question

What is the genotype of Drosophila showing normal wings?

Answer 1

To understand what a map unit (Centimorgan) represents in the construction of genetic maps, we must first understand the concept of genetic linkage and recombination.

A genetic map unit, also known as a centimorgan (cM), is a measure used in genetics to describe the distance between two genes on a chromosome. This distance is based on the frequency of recombination (crossing over) between genes during meiosis.

The correct answer is: A unit of distance between genes on chromosomes, representing 1% cross over. Let's break this down step-by-step:

Genetic Mapping: Genetic maps are used to determine the linear order and relative distance of genes on a chromosome. The distance between them is often indicated in map units or centimorgans.
Centimorgan (cM): One centimorgan corresponds to a 1% chance that a marker at one genetic locus will be separated from a marker at a second locus due to recombination in a single generation.
Recombination Frequency: If two genes are more than 50 cM apart, they are likely to assort independently and show a recombination frequency of 50%, signifying they're on different chromosomes or far apart on the same chromosome.
Elimination of Incorrect Options:
- 100% Crossover: This would imply that every time a crossover occurs between the two gene markers, which is incorrect as this doesn't reflect typical genetic distances.
- 50% Crossover: While it is possible, this proportion usually signifies independent assortment rather than linkage.

In summary, a map unit or centimorgan is a fundamental concept in genetic mapping that helps in determining the arrangement of genes on a chromosome based on recombination frequencies.

Answer 2

To understand what a map unit (Centimorgan) represents in the construction of genetic maps, we must first understand the concept of genetic linkage and recombination.

A genetic map unit, also known as a centimorgan (cM), is a measure used in genetics to describe the distance between two genes on a chromosome. This distance is based on the frequency of recombination (crossing over) between genes during meiosis.

The correct answer is: A unit of distance between genes on chromosomes, representing 1% cross over. Let's break this down step-by-step:

Genetic Mapping: Genetic maps are used to determine the linear order and relative distance of genes on a chromosome. The distance between them is often indicated in map units or centimorgans.
Centimorgan (cM): One centimorgan corresponds to a 1% chance that a marker at one genetic locus will be separated from a marker at a second locus due to recombination in a single generation.
Recombination Frequency: If two genes are more than 50 cM apart, they are likely to assort independently and show a recombination frequency of 50%, signifying they're on different chromosomes or far apart on the same chromosome.
Elimination of Incorrect Options:
- 100% Crossover: This would imply that every time a crossover occurs between the two gene markers, which is incorrect as this doesn't reflect typical genetic distances.
- 50% Crossover: While it is possible, this proportion usually signifies independent assortment rather than linkage.

In summary, a map unit or centimorgan is a fundamental concept in genetic mapping that helps in determining the arrangement of genes on a chromosome based on recombination frequencies.

A What map unit (Centimorgan) is adopted in the construction of genetic maps?

The Correct Option is C

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