HEREDITY
THE PEDIGREE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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They have same phenotype and genotype
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They have different phenotypes and genotypes
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They have same phenotype, but different genotypes
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They have different phenotypes, but the same genotype
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Detailed explanation-1: -One brother has genotype BB and the other brother has genotype Bb. Which statement is true about these two brothers? They have same phenotype, but different genotypes.
Detailed explanation-2: -Of these three genotypes, only bb, the homozygous recessive genotype, will produce a phenotype of blue eyes. The heterozygous genotype and the homozygous dominant genotype both will produce brown eyes, though only the heterozygous genotype can pass on the gene for blue eyes.
Detailed explanation-3: -There is a 75% chance of a brown-eyed child, because both Bb (50% chance) and BB (25% chance) genotypes result in brown eye phenotype. There is a 25% chance of a blue-eyed child, because only a bb genotype results in a blue eye phenotype.
Detailed explanation-4: -It’s possible for them to have a combination, or “Bb”, having one dominant brown allele and one recessive blue allele. In this case, because brown is dominant over blue, they will have brown eyes.
Detailed explanation-5: -Genotypes with two alleles that are the same, i.e. ‘BB’ and ‘bb’, are known as homozygous genotypes and genotypes with two different alleles are known as heterozygous genotypes.