Genotype and phenotype are words used in genetics to describe an organism’s appearance, function, and behaviour. A genotype is a collection of genes that, when expressed, determine an organism’s feature or attribute. To put it another way, the genotype is the genetic component of the phenotype.
DNA sequences are made up of genes. They come in pairs in humans and other animals, one from the male parent and the other from the female parent. Alleles are genetic pairings that share the same loci on the chromosomes and control the same characteristic.
A pair of genes (or alleles) for a certain trait often consists of two genes, one dominant and the other recessive. The dominant allele will show up as a characteristic, whereas the recessive allele will not. There are three genotypes that may be identified by annotating the dominant allele with A and the recessive allele with a:
(1) AA, homozygous dominant allele,
(2) Aa, heterozygous dominant, and
(3) aa, homozygous recessive.
An organism’s genotype is a key factor in determining its phenotype. A pair of genes (or alleles) for a specific trait is usually made up of two, one dominant and the other recessive. The dominant allele will manifest itself as a characteristic, while the recessive allele will not. The dominant allele is labelled with A, and the recessive allele is labelled with an in three possible genotypes:
(1) AA represents the homozygous dominant allele,
(2) Aa represents the heterozygous dominant allele, and
(3) aa represents the homozygous recessive allele.
An organism’s genotype is a significant determinant of its phenotype. Take, for example, a pair of alleles (or genes) that defines a certain characteristic, one of which is dominant (A) and the other recessive (B) (a). The dominant allele (A) will be expressed and form part of the organism’s phenotype, whereas the recessive allele (a) will be muted.
When a characteristic is inherited according to Mendelian principles, the A will appear as a trait, but the a will not. As a result, an organism’s phenotype must incorporate the characteristics of all expressed genes. Many observable characteristics in humans, however, are more complicated than those that follow the Mendelian pattern. In the case of polygenic inheritance, complex characteristics such as height and skin colour are caused by the interactions of many alleles.