Ch. 9 - The Molecular Biology of Translation

Sanders - Genetic Analysis: An Integrated Approach 3rd Edition

Sanders3rd EditionGenetic Analysis: An Integrated ApproachISBN: 9780135564172당신이 사용하는 게 아니라요?교과서 변경

Sanders 3rd Edition

Ch. 9 - The Molecular Biology of Translation

문제 B.1a

9장, 문제 B.1a

Answer the following questions for autosomal conditions such as PKU.
If both parents are heterozygous carriers of a mutant allele, what is the chance that their first child will be homozygous recessive for the mutation?

검증된 단계별 안내

Identify the inheritance pattern: Since the condition is autosomal recessive, the disease manifests only when an individual has two copies of the mutant allele (homozygous recessive).

Define the genotypes of the parents: Both parents are heterozygous carriers, meaning their genotype is

A a

, where

A

is the normal allele and

a

is the mutant allele.

Set up a Punnett square to determine the possible genotypes of their offspring by combining the alleles from each parent: the possible combinations are

AA

Aa

aA

, and

aa

Calculate the probability of the child being homozygous recessive (

aa

): count the number of

aa

outcomes over the total possible outcomes in the Punnett square.

Express the probability as a fraction or percentage to represent the chance that the first child will be homozygous recessive for the mutation.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.

영상 길이:

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Autosomal Recessive Inheritance

Autosomal recessive inheritance occurs when a trait or disorder is expressed only if an individual inherits two copies of a mutant allele, one from each parent. Carriers have one normal and one mutant allele but typically do not show symptoms. Diseases like PKU follow this pattern.

Genotype Probability in Offspring

When both parents are heterozygous carriers (Aa), the possible genotypes for their child are AA, Aa, or aa. Using a Punnett square, the probability of the child being homozygous recessive (aa) is 25%, as each allele is inherited independently.

Phenotypic Expression of Homozygous Recessive

Individuals who are homozygous recessive (aa) for a mutation typically express the autosomal recessive condition, such as PKU. This means the disease phenotype manifests only when both alleles are mutant, highlighting the importance of genotype in predicting disease risk.

Answer the following questions for autosomal conditions such as PKU.If both parents are heterozygous carriers of a mutant allele, what is the chance that their first child will be homozygous recessive for the mutation?