Table of contents

Skip topic navigation

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

1. Introduction to Genetics

Fundamentals of Genetics

Genetics

1. Introduction to Genetics

Fundamentals of Genetics

Previous problemNext problem

Struggling with Genetics?

Join thousands of students who trust us to help them ace their exams!Watch the first video

Multiple Choice

Any two matched genes that are __________ are called alleles.

identical in nucleotide sequence

expressed only in the phenotype

located at the same locus on homologous chromosomes

found on different chromosomes

Previous problemNext problem

Verified step by step guidance

Understand the definition of alleles in genetics: Alleles are different versions of the same gene that occupy the same position, or locus, on homologous chromosomes.

Recall that homologous chromosomes are pairs of chromosomes, one inherited from each parent, that have the same genes at the same loci but may have different alleles.

Recognize that alleles are not necessarily identical in nucleotide sequence; they can vary, which leads to genetic variation.

Note that alleles are not defined by their expression in the phenotype alone, as some alleles may be recessive and not expressed.

Conclude that the key characteristic of alleles is that they are located at the same locus on homologous chromosomes, which distinguishes them from genes found on different chromosomes.