NEET BIOLOGY

GENETICS AND EVOLUTION

GENETIC BASIS OF INHERITANCE

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Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]

Genes A, B, and C have these map distances between them:A and B-15 map units; B and C-5 map units; A and C-10 map units. What is the relative order of the three genes on the chromosome?

A	ACB
B	ABC
C	BAC
D	CAB

Explanation:

Detailed explanation-1: -The map distances between genes A and B is 3 units, between B anc C is 10 units and between C and A is 7 units. The order of the genes in a linkage map constructed on the above data would perhaps be: Q.

Detailed explanation-2: -Gene map distance is the distance between points on a chromosome which can be estimated by counting the number of crossovers between them. Therefore, the distance between two points on the genetic map of a chromosome is the average number of crossovers between them.

Detailed explanation-3: -The distance between the genes a, b, c and d in mapping units are a-d = 3.5; b-c = 1; a-b = 6; c-d = 1.5 and a-c = 5.

Detailed explanation-4: -The cross over frequencies between the genes A and B, A and C, and B and C is 6%, 15% and 21% respectively.

There is 1 question to complete.