Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

29. Heredity

Patterns of Inheritance

Anatomy & Physiology

29. Heredity

Patterns of Inheritance

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Problem 15

Textbook Question

A normally pigmented woman whose father was an albino marries a normally pigmented man whose mother was an albino. What is the probability that they would have an albino child?
(a) 50 percent
(b) 25 percent
(c) 12.5 percent
(d) 6.25 percent
(e) 100 percent

Verified step by step guidance

Step 1: Understand the genetic basis of albinism. Albinism is typically inherited as an autosomal recessive trait, meaning that an individual must inherit two copies of the recessive allele (aa) to express the condition. A person with normal pigmentation can be a carrier (Aa) if they have one recessive allele and one dominant allele.

Step 2: Determine the genotypes of the parents based on the information provided. The woman is normally pigmented but her father was an albino, so her genotype must be heterozygous (Aa). Similarly, the man is normally pigmented but his mother was an albino, so his genotype must also be heterozygous (Aa).

Step 3: Set up a Punnett square to analyze the possible genetic combinations of the offspring. Each parent contributes one allele to the child. The possible combinations are: AA (normal pigmentation), Aa (carrier with normal pigmentation), Aa (carrier with normal pigmentation), and aa (albino).

Step 4: Calculate the probability of each genotype. From the Punnett square, there is a 1 in 4 chance (25%) that the child will inherit two recessive alleles (aa) and be albino.

Step 5: Verify the probability and match it to the answer choices provided. The probability of having an albino child is 25%, which corresponds to option (b).

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Genetics and Inheritance Patterns

Understanding basic genetics is crucial for this question, particularly the concepts of dominant and recessive traits. Albinism is typically a recessive trait, meaning that an individual must inherit two copies of the albino allele (one from each parent) to express the condition. The inheritance pattern follows Mendelian principles, where traits are passed from parents to offspring based on allele combinations.

Punnett Squares

A Punnett square is a tool used to predict the genetic outcomes of a cross between two individuals. By mapping the alleles of each parent, one can visualize the potential genotypes of their offspring. This method is essential for calculating the probability of specific traits, such as albinism, in the children of the couple described in the question.

Probability in Genetics

Probability in genetics involves calculating the likelihood of inheriting certain traits based on allele combinations. In this scenario, understanding how to determine the probability of having an albino child requires knowledge of the parents' genotypes and the possible combinations of alleles. This concept is fundamental for arriving at the correct answer regarding the likelihood of albinism in their offspring.

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