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

Previous problemNext problem

Problem 24c

Textbook Question

Indicate the type of inheritance involved in each of the following situations.
(c) The trait is expressed more commonly in sons than in daughters.

Verified step by step guidance

Understand the concept of inheritance patterns: Traits can be inherited through autosomal or sex-linked inheritance. Sex-linked inheritance involves genes located on sex chromosomes (X or Y).

Recognize that traits expressed more commonly in sons than in daughters often suggest X-linked inheritance. This is because males have only one X chromosome, so a recessive allele on the X chromosome will be expressed in males.

Recall that females have two X chromosomes, so they would need two copies of the recessive allele for the trait to be expressed. This makes the trait less common in daughters.

Consider examples of X-linked traits, such as hemophilia or color blindness, which are more frequently observed in males due to the inheritance pattern.

Conclude that the type of inheritance involved in this situation is likely X-linked recessive inheritance, based on the description of the trait being more common in sons than daughters.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Play a video:

Was this helpful?

Key Concepts

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

Sex-Linked Inheritance

Sex-linked inheritance refers to traits that are associated with genes located on sex chromosomes, particularly the X and Y chromosomes. In many cases, traits linked to the X chromosome are expressed differently in males and females due to the presence of only one X chromosome in males (XY) compared to two in females (XX). This can lead to certain traits being more commonly expressed in males, especially if the trait is recessive.

Autosomal vs. Sex-Linked Traits

Autosomal traits are those determined by genes located on non-sex chromosomes (autosomes), while sex-linked traits are influenced by genes on sex chromosomes. Understanding the distinction is crucial for determining inheritance patterns. If a trait is expressed more in sons than daughters, it often indicates a sex-linked inheritance pattern, particularly if the trait is recessive and located on the X chromosome.

Recessive and Dominant Alleles

Alleles can be classified as dominant or recessive based on their expression in the phenotype. A dominant allele will mask the effect of a recessive allele in a heterozygous individual. In the context of sex-linked traits, if a recessive allele is present on the X chromosome, it may be expressed in males who have only one X chromosome, leading to a higher prevalence of the trait in sons compared to daughters.

Watch next

Master Mendel's Laws with a bite sized video explanation from Bruce Bryan

Start learning

Related Videos

Related Practice

Textbook Question

Indicate the type of inheritance involved in each of the following situations.

(b) Children exhibit the trait even though neither parent does.

views

Textbook Question

Indicate the type of inheritance involved in each of the following situations.

(d) The trait is expressed equally in daughters and sons.

views

Textbook Question

Distinguish between the following paired terms:

views

Textbook Question

Recessive X-linked traits

(a) Are passed from fathers to their sons

(b) Are more likely to be expressed in males

(d) Are never expressed in females

(e) Cannot be passed from mothers to daughters

views

Textbook Question

Hemophilia A, a condition in which blood does not clot properly, is a recessive trait located on the X chromosome (Xʰ). Suppose that a woman who is heterozygous for this trait (XXʰ) has children with a normal male (XY). What is the probability that the couple will have daughters with hemophilia? What is the probability that the couple will have sons with hemophilia?

views

Textbook Question

Distinguish between the following paired terms:

(b) heterozygous and homozygous,

views

Multiple Choice

An allele that is able to mask the expression of its partner allele is said to be __________.

870

views

Multiple Choice

Codominant alleles are present in __________.

888