What is the role of alleles in determining traits?

Alleles are different forms of the same gene that occupy the same position (locus) on homologous chromosomes. They play a central role in determining traits by influencing how a particular characteristic is expressed.

Each individual inherits two alleles for a gene- one from each parent. These alleles can be identical (homozygous) or different (heterozygous). The interaction between these alleles determines the phenotype (observable trait).

In cases of dominant and recessive alleles, the dominant allele masks the effect of the recessive allele in heterozygous conditions. For example, if “A” is dominant and “a” is recessive, individuals with Aa will show the dominant trait.

In some cases, alleles may show incomplete dominance, where the phenotype is intermediate, or codominance, where both alleles are equally expressed.

Alleles also contribute to genetic variation within a population, as different combinations lead to diverse traits.

Overall, alleles are the functional units that determine how genetic information is expressed, directly influencing the characteristics of an organism.