What Are Multiple Allele Traits?

Traits controlled by a single gene with more than two alleles are called multiple allele traits. Unlike Mendel's pea plants, the trait is influenced by two or more alleles.

For example, in labrador retrievers, black is dominant to brown, but if the dog inherits two copies of the yellow allele (ee), then the dog will be yellow in color.

Gene:

• A gene is a specific sequence of DNA located at a particular position on a chromosome.
• Genes contain the instructions for building and controlling specific traits or characteristics.
• Each gene has a specific function and can influence various traits, such as eye color, height, or susceptibility to certain diseases.
• Genes are passed from parents to offspring during reproduction and determine the genetic makeup of an individual.

Allele:

• An allele is a specific version or variant of a gene.
• Alleles arise from mutations or genetic variations in the DNA sequence of a gene.
• Different alleles of the same gene can result in variations in traits or characteristics.
• Alleles occupy the same position (locus) on homologous chromosomes and can be either dominant or recessive.
• Individuals inherit two alleles for each gene, one from each parent, which may be the same (homozygous) or different (heterozygous).

Examples of Multiple Allele Traits

1. Human Blood Types: There are three alleles for the gene that determines blood type: A, B, and O. Each individual inherits two of these alleles, resulting in possible blood types such as A, B, AB, or O

2. Human eye color: Although eye color is influenced by multiple genes, one of the major genes involved is the OCA2 gene (oculocutaneous albinism II). This gene has multiple alleles that contribute to variations in eye color, including brown, blue, green, and gray.

3. Coat color in animals: Many animals, including mice, dogs, and horses, have coat color genes with multiple alleles. For example, the alleles of labrodor retrieves and for rabbit coat color.
   
   
4. Seed coat color in plants: In plants such as peas, the gene responsible for seed coat color, known as the C gene, has multiple alleles that produce different seed coat colors, including yellow, green, and gray.
   
   
5. Corn snake color and patterns: Corn snakes can be red and black, red and white, all white.

Punnett Square Showing Inheritance Pattern of Multiple Allele Trait