Table of contents

1. Introduction to Genetics51m
2. Mendel's Laws of Inheritance3h 37m
3. Extensions to Mendelian Inheritance2h 41m
4. Genetic Mapping and Linkage2h 28m
5. Genetics of Bacteria and Viruses1h 21m
6. Chromosomal Variation1h 48m
7. DNA and Chromosome Structure56m
8. DNA Replication1h 10m
9. Mitosis and Meiosis1h 34m
10. Transcription1h 0m
11. Translation58m
12. Gene Regulation in Prokaryotes1h 19m
13. Gene Regulation in Eukaryotes44m
14. Genetic Control of Development44m
15. Genomes and Genomics1h 50m
16. Transposable Elements47m
17. Mutation, Repair, and Recombination1h 6m
18. Molecular Genetic Tools19m
- Genetic Cloning
  9m
- Methods for Analyzing DNA
  9m
19. Cancer Genetics29m
- Overview of Cancer
  21m
- Cancer Mutations
  7m
20. Quantitative Genetics1h 26m
21. Population Genetics50m
- Hardy Weinberg
  19m
- Allelic Frequency Changes
  31m
22. Evolutionary Genetics29m

2. Mendel's Laws of Inheritance

Sex-Linked Genes

Genetics

2. Mendel's Laws of Inheritance

Sex-Linked Genes

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Multiple Choice

Since the allele for colorblindness is located on the X chromosome, colorblindness:

can only be passed from father to son

is inherited equally by males and females

is caused by a dominant allele

is more common in males than in females

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Verified step by step guidance

Understand that colorblindness is a sex-linked trait located on the X chromosome, meaning the gene responsible is found on the X chromosome but not on the Y chromosome.

Recall that males have one X and one Y chromosome (XY), while females have two X chromosomes (XX). This difference affects how X-linked traits are inherited.

Recognize that because males have only one X chromosome, if they inherit the allele for colorblindness on their single X chromosome, they will express the trait, as there is no second X chromosome to mask the effect.

In contrast, females must inherit two copies of the allele (one on each X chromosome) to express the trait, making it less common in females since they can be carriers if they have only one affected X chromosome.

Conclude that colorblindness is more common in males than females because males need only one copy of the recessive allele on their single X chromosome to be affected, whereas females need two copies.