HESI A2 Biology Practice Test

Alleles are alternative versions of a gene that arise from mutations and occur at the same locus on homologous chromosomes. Each gene can have multiple alleles, leading to variations in traits, such as flower color or blood type. For instance, in pea plants, the gene for flower color can exist as a purple allele or a white allele. These different versions of the gene result in observable differences in characteristics. Understanding alleles is crucial in genetics as they contribute to the variation in traits among individuals within a population. This is a fundamental concept in heredity and evolution since the combination of alleles inherited from parents determines the genotype and contributes to the phenotype of an organism. The presence of various alleles in a population is also essential for natural selection and contributes to genetic diversity.