Experiments 1 and 2: Genetics In order to define potential effects of the presen

    Experiments 1 and 2: Genetics
    In order to define potential effects of the presence/absence of the Itga7 protein on the
    inheritance patterns a number of breedings were performed. The genotypes of the parents
    were known and the genotypes of the litters (age: 14-16 days) were analysed by allele-specific
    PCR reactions.Experiment 1:(Marks: 10)
    In three parallel experiments (1.1 1.2 1.3) crossings of 5 wildtype males (Itga7+/+) with 10
    heterozygous females (Itga7+/-) were started and all litters (Total number of mice) were
    genotyped and the numbers of all possible genotypes are given in the following Table 1. All
    mice tested appear normal and show no altered phenotype at the tested age.
    Breeding: m(Itga7+/+) x f(Itga7+/- )
    Table 1:
    Experiment
    1.1
    1.2
    1.3
    Litters
    Total number
    42
    68
    70
    Genotypes
    Itga7+/+
    20
    32
    31
    Itga7+/-
    22
    36
    39
    Itga7-/-
    0
    0
    0
    Corrected version: 19. November 2012
    Experiment 2:(Marks: 20)
    In three parallel experiments (2.1 2.2 2.3) crossings of 5 heterozygous males (Itga7+/-) with 10
    heterozygous females (Itga7+/-) from experiment 1 were started all litters were again
    genotyped and the numbers of all possible genotypes are given in the following Table 2.
    Breeding: m(Itga7+/-) x f(Itga7+/- )
    Table 2:
    Experiment
    2.1
    2.2
    2.3
    Sum (2.1-2.3)
    Litters
    Total
    55
    60
    37
    Genotypes
    Itga7+/+
    13
    19
    13
    Itga7+/-
    34
    33
    20
    Itga7-/-
    8
    8
    4
    Questions to answer:
    (A) Discuss briefly which type of genetic inheritance would be most adequate to describe the
    distribution of genotypes?
    (B) Does the distribution of genotypes (numbers of mice) in experiments 1 and 2 correspond to
    the expected numbers according to Mendelian laws?
    (C) Are there any further conclusions on phenotypes possible? If yes what could be possible
    reasons?

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