Suppose a genotype for a protein-producing gene can have any combination of three alleles, A₁, A₂, and A₃.

Each allele produces a protein with a distinct electrophoretic mobility. Allele A₁ has the highest electrophoretic mobility, A₃ has the lowest electrophoretic mobility, and the electrophoretic mobility of A₂ is intermediate between them. Draw the appearance of gel electrophoresis protein bands for each of the possible genotypes. Be sure to label each lane of the gel with the corresponding genotype.

Key Concepts

Alleles and Genotypes

Alleles are different versions of a gene that can produce variations in traits. In this scenario, the alleles A₁, A₂, and A₃ represent different forms of a protein-producing gene. A genotype refers to the specific combination of alleles an individual possesses, which can influence the phenotype, or observable traits, such as protein production.

Electrophoretic Mobility

Electrophoretic mobility is a measure of how quickly a protein moves through a gel when an electric current is applied. This movement is influenced by the protein's size and charge. In this case, the alleles produce proteins with distinct mobilities: A₁ moves fastest, A₂ has intermediate mobility, and A₃ moves slowest, which will be reflected in the gel electrophoresis results.

Gel Electrophoresis

Gel electrophoresis is a laboratory technique used to separate proteins based on their size and charge. In this process, a gel matrix is used to create a medium through which proteins migrate when an electric field is applied. The resulting bands on the gel correspond to different genotypes, allowing for visual identification of the alleles present in each sample based on their electrophoretic mobility.