In gel electrophoresis, how can you determine if an individual is heterozygous for a gene?

In gel electrophoresis, an individual who is heterozygous for a gene carries two different alleles at a specific gene locus. When the DNA or RNA fragments from this individual are subjected to electrophoresis, the differing sizes or sequences of the alleles are manifested as distinct bands on the gel.

When an individual is heterozygous, the different alleles will travel through the gel matrix at slightly different rates, resulting in two separate and distinct bands. These bands correspond to the variations of the gene present, showcasing both alleles that the individual possesses.

This characteristic banding pattern is critical for genetic analysis, as heterozygosity can indicate genetic diversity and is often associated with various traits and genetic conditions. Thus, the presence of two distinct bands confirms that the individual has inherited two different versions of the same gene, indicating heterozygosity.