Principles of Inheritance and Variation


  1. The genes controlling the seven pea characters studied by Mendel are now known to be located on how many different chromosomes?









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    The seven traits are now know to be present on 4 chromosome. But they do not show linkage, because of large distances between them on the chromosome.

    Correct Option: A

    The seven traits are now know to be present on 4 chromosome. But they do not show linkage, because of large distances between them on the chromosome.


  1. Which one of the following traits of garden pea studied by Mendel was a recessive feature?









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    Yellow seed colour is dominant over green seed colour.

    Correct Option: C

    Yellow seed colour is dominant over green seed colour.



  1. Which Mendelian idea is depicted by a cross in which the F1 generation resembles both the parents?









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    In Co-dominance F1 generation resemble both the parents. Ex: Blood group inheritance.

    Correct Option: C

    In Co-dominance F1 generation resemble both the parents. Ex: Blood group inheritance.


  1. If two persons with ‘AB’ blood group marry and have sufficiently large number of children these children could be classified as ‘A’ blood group: ‘AB’ blood group: ‘B’ blood group in 1: 2: 1 ratio. Modern technique of protein electrophoresis reveals presence of both ‘A’ and ‘B’ type proteins in ‘AB’ blood group individuals. This is an example of:









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    ABO blood group system in human beings is an example of codominant, dominant recessive and multiple alletes. Blood groups are controlled by the gene I located on 9th chromosome that has 3 multiple alleles, out of which any two are found in a person. In codominance both gene express it self completely.

    Correct Option: D

    ABO blood group system in human beings is an example of codominant, dominant recessive and multiple alletes. Blood groups are controlled by the gene I located on 9th chromosome that has 3 multiple alleles, out of which any two are found in a person. In codominance both gene express it self completely.



  1. In a population of 1000 individuals 360 belong to genotype AA, 480 to Aa and the remaining 160 to aa. Based on this data, the frequency of allele A in the population is:









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    According to Hardy Weinberg principle.
    p2 + 2pq + q2 = 1; (p + q)2 = 1
    (AA) p2 = 360 out of 1000 individual or p2 = 36 out of 100.
    q2 = 160 out of 1000 or q2 = 16 out of 100
    so q = √.16 = .4, As p + q = 1
    so p is 0.6.

    Correct Option: C

    According to Hardy Weinberg principle.
    p2 + 2pq + q2 = 1; (p + q)2 = 1
    (AA) p2 = 360 out of 1000 individual or p2 = 36 out of 100.
    q2 = 160 out of 1000 or q2 = 16 out of 100
    so q = √.16 = .4, As p + q = 1
    so p is 0.6.