What are alleles?

What are alleles?

• A. Different versions of the same gene
• B. Segments of DNA that code for traits
• C. Chromosome pairs
• D. Physical traits

Answer: (A)

Alleles are different versions of the same gene at the same location on homologous chromosomes. They arise from small DNA sequence differences and create variation in how traits are inherited and expressed. In diploid organisms, you usually have two alleles for each gene, one from each parent, and the interaction between those alleles (such as dominant vs recessive, or codominant relationships) determines the trait you see. It’s helpful to keep straight that a gene is the DNA segment that encodes a product, while alleles are the variant forms of that gene, and traits are the observable outcomes influenced by which alleles are present and how they interact with the environment. For example, a gene involved in pigmentation can have alleles that lead to different eye or skin colors.

Alleles are different versions of the same gene at the same location on homologous chromosomes. They arise from small DNA sequence differences and create variation in how traits are inherited and expressed. In diploid organisms, you usually have two alleles for each gene, one from each parent, and the interaction between those alleles (such as dominant vs recessive, or codominant relationships) determines the trait you see. It’s helpful to keep straight that a gene is the DNA segment that encodes a product, while alleles are the variant forms of that gene, and traits are the observable outcomes influenced by which alleles are present and how they interact with the environment. For example, a gene involved in pigmentation can have alleles that lead to different eye or skin colors.