PATHOLOGY MCQ
GENETICS AND DISEASE
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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0 BB:2 Bb:2bb
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1 BB:2 Bb:1 bb
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2 BB:0 Bb:2 bb
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2 BB:1 Bb:0 bb
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Detailed explanation-1: -In cocker spaniels the allele for a black coat color (B) is dominant over the allele for a brown coat color (b). If a brown cocker spaniel (bb) is crossed with a heterozygous black cocker spaniel (Bb), how many of the offspring may be brown (bb)? All offspring will have short-haired fur.
Detailed explanation-2: -In cocker spaniels, black coat color (B) is dominant over red (b), and solid color (S) is dominant over spotted (s).
Detailed explanation-3: -Dogs with B/b genotype are expected to express undiluted black pigment and are carriers of brown. They will transmit the brown allele to 50% of their offspring.
Detailed explanation-4: -Finally, the genotype of an organism with two recessive alleles is called homozygous recessive. In the eye color example, this genotype is written bb.
Detailed explanation-5: -Normal fruit flies have brownish-yellow bodies, and this body color is dominant. A mutation in the gene for body color can produce flies with an ebony body color. A homozygous normal fruit fly (e+e+) is crossed with a homozygous ebony fruit fly (ee).