Alleles

An allele is a variant form of a gene that arises by mutation and is located at a specific position on a specific chromosome. Alleles can result in different traits or characteristics in an organism. Each individual carries two alleles for each gene, one inherited from each parent.

Key Points to Remember

• Alleles are different forms of a gene that can lead to different traits in an organism.
• Each individual carries two alleles for each gene, one from each parent.
• Alleles can be dominant or recessive, and they can interact in various ways to determine the traits of an organism.
• Alleles are located at specific positions on chromosomes.

Examples of Alleles

Examples of alleles include:

• Eye color: There are different alleles for eye color, such as brown, blue, green, etc.
• Blood type: Alleles for blood type include A, B, and O.
• Seed shape in plants: Alleles for seed shape can be round or wrinkled.

Study Questions

1. What is an allele?
2. How many alleles does an individual carry for each gene?
3. What are dominant and recessive alleles?
4. Give an example of a trait determined by alleles.

Answers to Study Questions

1. An allele is a variant form of a gene that arises by mutation and is located at a specific position on a specific chromosome.
2. An individual carries two alleles for each gene, one from each parent.
3. Dominant alleles are expressed as a trait when present, while recessive alleles are only expressed when two copies are present.
4. Example: Eye color, blood type, seed shape in plants.