GENETICS AND EVOLUTION
INHERITANCE AND VARIATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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A unit of distance between two expressed genes representing 10% cross over.
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A unit of distance between two expressed genes representing 100% cross over.
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A unit of distance between genes on chromosomes, representing 1% cross over.
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A unit of distance between genes on chromosomes, representing 50% cross over.
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Detailed explanation-1: -It is often used to guess the distance along a chromosome but this map unit is not a true physical distance. Hence, the correct answer is option (C). Note: A centimorgan or map unit is a unit which is used for the measurement of genetic distance.
Detailed explanation-2: -In genetics, a centimorgan (abbreviated cM) or map unit (m.u.) is a unit for measuring genetic linkage. It is defined as the distance between chromosome positions (also termed loci or markers) for which the expected average number of intervening chromosomal crossovers in a single generation is 0.01.
Detailed explanation-3: -A centimorgan (abbreviated cM) is a unit of measure for the frequency of genetic recombination. One centimorgan is equal to a 1% chance that two markers on a chromosome will become separated from one another due to a recombination event during meiosis (which occurs during the formation of egg and sperm cells).
Detailed explanation-4: -The recombination percentage depends on the distance between genes on chromosomes. The unit of a genetic map is called a centiMorgan, and one centiMorgan corresponds to one percentage recombination frequency.
Detailed explanation-5: -CentiMorgan (cM) is a unit to measure the distance between genes on the chromosome. It is denoted by map unit. One centiMorgan is equal to one map unit and same will be the recombination frequency. The recombination rate varies not only among the individuals but also the chromosomes.