GENETICS AND EVOLUTION
EVOLUTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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The baby inherits the dominant allele from his father.
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The allele is on an autosomal chromosome and the baby is a twin
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The allele is on the X chromosome.
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The allele is on the Y chromosome.
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Detailed explanation-1: -The baby boy’s mother would give him his only X chromosome, as his father would need to give him the Y chromosome for him to be male. Thus, if his mother gave him a recessive allele on the X chromosome, the boy would express it.
Detailed explanation-2: -In which circumstance would he most likely show the trait coded for by the recessive allele? The baby inherits the dominant allele from his father.
Detailed explanation-3: -What is the probability that a male will inherit a recessive allele from his mother? The probability that a daughter will inherit a recessive allele from her mother is 100%; the probability that a son will inherit a recessive allele from his mother is 50%.
Detailed explanation-4: -Recessive inheritance means both genes in a pair must be abnormal to cause disease. People with only one defective gene in the pair are called carriers. These people are most often not affected with the condition. However, they can pass the abnormal gene to their children.
Detailed explanation-5: -If two heterozygous parents had a child, their cross would be Bb x Bb. There is a 25% chance they would have a child with a recessive genotype which would also be the percentage with a recessive genotype. This is because for a recessive phenotype to be expressed, there must be two recessive allele (bb).