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Frequency of recombination between gene pairs on same chromosome as a measure of the distance between genes to map their position on chromosome, was used for the first time by 

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Important Questions on Heredity and Variation

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Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
Select the correct statement.
HARD
Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
In a testcross involving F1 dihybrid flies, more parental-type offspring were produced than the recombinant-type offspring. This indicates:
MEDIUM
Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over

Given below are two statements one is labelled as: Assertion (A) and the other is labelled as Reason (R).

Assertion (A): Mendel's law of independent assortments does not hold good for the genes that are located closely on the same chromosome.

Reason (R): Closely located genes assort independently.

In light of the above statements, choose the correct answer from the options given below:

MEDIUM
Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
Identify the incorrect statement from the following.
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Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
With increasing age, the linkage ___.
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Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
What map unit (Centimorgan) is adopted in the construction of genetic maps?
HARD
Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
The recombination frequency between the genes a and c is 5%, b and c is 15%, b and d is 9%, a and b is 20%, c and d is 24% and a and d is 29%. What will be the sequence of these genes on a linear chromosome?
MEDIUM
Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
A plant heterozygous for height and flower colour TtRr are selfed and 1600 of the resulting seeds are planted. If the distance between the loci controlling height and the flower colour is 1 centiMorgan (cM), then how many offsprings are expected to be short with white flower ttrr? 
MEDIUM
Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
In a dihybrid cross between genes yellow, white and miniature characters, the parental % between yellow and white and recombination % is 92 and 8 respectively, and the cross between white and miniature characters, the recombination is 38% and parental is 62%. Identify the genetic map of these.
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Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
The frequency of recombination between gene pairs on the same chromosome as a measure of the distance gene was explained by:
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Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
The term ''linkage'' was coined by:
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Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
All genes located on the same chromosome
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Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
Genetic map is one that
HARD
Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
The experiment shown in the figure has been carried out by Morgan to show the phenomenon of linkage and recombination. If in cross-I genes are tightly linked and in cross-II, genes are loosely linked then what will be the percentage of recombinants produced in cross-I & cross-II respectively ?

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EASY
Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
How much linkage strength is present between two genes A & B, which are 6 cM far from each other in a chromosome?
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Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
In Morgan's experiment, what will be percentage of recombination in case of body colour and eye colour?
HARD
Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
In Drosophila cross, the heterozygous member with grey body (b+) and long wings (vg+) was crossed with black body and vestigial wings, the progeny had the following ratio; grey vestigial 24: grey long 126: black long 26: black vestigial 124. What is the frequency of recombinants in the population?
MEDIUM
Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
In Drosophila, the allele for normal grey body colour (G) is dominant to ebony body (g). The following table summarises the results of several crosses:-
 
Cross Result
Strain 1 × gg All Grey type
Strain 2 × gg 1 Grey : 1 ebony
Strain 3 × gg All ebony type
Strain 4 × Gg 3 Grey : 1 ebony

Which strains have the genotype Gg ?
HARD
Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
The experiment carried out by Morgan is shown in the figure to explain the phenomenon of linkage and recombination. If in cross-I, genes are tightly linked and in cross-II, genes are loosely linked then what will be the percentage of recombinants produced in cross-I and cross-II respectively?
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MEDIUM
Biology>Genetics and Evolution>Heredity and Variation>Linkage and Crossing Over
Two genes ‘A’ and 'B’ are linked. In a dihybrid cross involving these two genes, the F1 heterozygote is crossed with homozygous recessive parental type (aa bb). What would be the ratio of offspring in the next generation?