Pedigrees Practice - Human Genetic Disorders 1 .pdf - Name: Aimee ... - Free Printable

Problem Analysis:

The image contains a genetics practice worksheet focusing on Mendelian Genetics. The task involves analyzing a pedigree chart to determine the inheritance pattern of a trait and answering related questions. Let's break it down step by step.

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Pedigree Chart Description:

1. Symbols in the Pedigree:
- Squares represent males.
- Circles represent females.
- Shaded symbols indicate individuals with the trait (affected).
- Unshaded symbols indicate individuals without the trait (unaffected).

2. Key Observations:
- The trait appears to be inherited across generations.
- Both males and females are affected, suggesting it is not sex-linked (e.g., X-linked or Y-linked).
- Affected individuals appear in multiple generations, indicating a heritable pattern.

3. Questions to Answer:
- Part A: What type of inheritance does this pedigree show?
- Part B: Does RFLP analysis support this result?

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Step-by-Step Solution:

#### Part A: Type of Inheritance
To determine the type of inheritance, we analyze the pattern of the trait in the pedigree:

1. Affected Individuals:
- Both males and females are affected, so it is not sex-linked.
- The trait appears in multiple generations, suggesting it is heritable.

2. Pattern of Transmission:
- Autosomal Dominant (AD):
- If one parent is affected, at least half of their offspring will inherit the trait.
- Affected individuals can have unaffected parents if they inherited the recessive allele from both parents.
- In the pedigree, some affected individuals have unaffected parents, which is consistent with autosomal dominant inheritance.
- Autosomal Recessive (AR):
- Both parents must be carriers (heterozygous) for an affected offspring to occur.
- Affected individuals cannot have unaffected parents unless there is a mutation.
- In the pedigree, some affected individuals have unaffected parents, which contradicts AR inheritance.
- X-Linked Dominant (XD):
- Males would typically be more severely affected than females.
- Females could be carriers but not necessarily affected.
- This does not fit the observed pattern since both males and females are equally affected.
- X-Linked Recessive (XR):
- Males would be primarily affected, and females would be carriers.
- This does not fit the observed pattern since both males and females are equally affected.

3. Conclusion:
- The pattern of inheritance is consistent with autosomal dominant (AD) because:
- Affected individuals can have unaffected parents.
- Both males and females are equally affected.

#### Answer to Part A:
The pedigree shows autosomal dominant (AD) inheritance.

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#### Part B: RFLP Analysis
RFLP (Restriction Fragment Length Polymorphism) analysis is a molecular technique used to identify specific DNA sequences. It can help confirm the presence of a genetic marker associated with a trait.

1. How RFLP Supports AD Inheritance:
- In autosomal dominant inheritance, the affected individual carries at least one copy of the mutant allele.
- RFLP analysis can detect the presence of the mutant allele in the DNA of affected individuals.
- If the mutant allele is consistently found in all affected individuals and absent in unaffected individuals, it supports the hypothesis of AD inheritance.

2. Expected Results:
- If RFLP analysis identifies a specific DNA fragment (marker) that is present in all affected individuals and absent in unaffected individuals, it strongly supports the conclusion of AD inheritance.
- Conversely, if the marker is not consistently linked to the trait, it may suggest a different inheritance pattern.

#### Answer to Part B:
If RFLP analysis identifies a specific DNA marker that is present in all affected individuals and absent in unaffected individuals, it supports the conclusion of autosomal dominant inheritance.

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Final Answers:

1. Part A: The pedigree shows autosomal dominant (AD) inheritance.
2. Part B: Yes, RFLP analysis supports this result if the DNA marker is consistently linked to the trait in all affected individuals.

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Boxed Final Answer:

$$
\boxed{\text{Autosomal Dominant (AD)}}
$$