Determine whether the statements below are true or false. If a statement is false, provide the correct information or revise the statement to make it correct.
If a woman is heterozygous for albinism, an autosomal recessive condition that results in the absence of skin pigment, the proportion of her gametes carrying the allele that allows pigment expression is expected to be 75%.

검증된 단계별 안내

Step 1: Understand the genetic basis of albinism. Albinism is an autosomal recessive condition, meaning that an individual must inherit two recessive alleles (aa) to express the condition. A heterozygous individual (Aa) carries one dominant allele (A) and one recessive allele (a).

Step 2: Recall the concept of gamete formation during meiosis. In a heterozygous individual (Aa), the alleles segregate equally during gamete formation, resulting in 50% of the gametes carrying the dominant allele (A) and 50% carrying the recessive allele (a).

Step 3: Analyze the statement provided. The statement claims that the proportion of gametes carrying the allele for pigment expression (dominant allele A) is 75%. This is inconsistent with Mendel's law of segregation, which states that alleles segregate equally.

Step 4: Revise the statement to make it correct. The correct proportion of gametes carrying the allele for pigment expression (A) in a heterozygous individual (Aa) is 50%, not 75%.

Step 5: Conclude that the statement is false and provide the corrected information: If a woman is heterozygous for albinism, the proportion of her gametes carrying the allele that allows pigment expression is expected to be 50%.

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주요 개념

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Heterozygosity

Heterozygosity refers to the presence of two different alleles at a specific gene locus. In the context of albinism, if a woman is heterozygous, she has one normal allele (for pigment production) and one recessive allele (for albinism). This genetic makeup influences the types of gametes she can produce, specifically affecting the expression of traits in offspring.

Autosomal Recessive Inheritance

Autosomal recessive inheritance occurs when a trait is expressed only when an individual has two copies of the recessive allele. In the case of albinism, an individual must inherit the recessive allele from both parents to exhibit the condition. If only one recessive allele is present, the dominant allele will mask its effect, leading to normal pigmentation.

Gamete Formation and Allele Distribution

During gamete formation, specifically through meiosis, alleles segregate so that each gamete receives only one allele from each gene pair. For a heterozygous individual (e.g., Aa), the gametes will carry either the dominant allele (A) or the recessive allele (a) in equal proportions, resulting in 50% of the gametes carrying the allele for pigment expression, not 75%.