What is an Allelomorph and Why is it Important?
An allelomorph, also known as an allele, is a variation of the same sequence of nucleotides at the same place on a long DNA molecule. Alleles are responsible for the diversity of traits that we observe in living organisms, such as eye color, blood type, and height. In this article, we will explain what allelomorphs are, how they are inherited, and how they affect the phenotype of an organism.
Allelomorphs and Genes
A gene is a segment of DNA that codes for a specific protein or function. Each gene has a specific location on a chromosome, called a locus. A chromosome is a long strand of DNA that contains many genes. Humans have 23 pairs of chromosomes, one pair inherited from each parent.
Allelomorphs are different versions of the same gene that may occur at the same locus on a chromosome. For example, the gene for eye color has several allelomorphs, such as brown, blue, and green. Each allelomorph produces a different pigment that determines the color of the iris.
Allelomorphs and Genotype
The combination of allelomorphs that an organism carries for a given gene is called its genotype. An organism can have two identical allelomorphs (homozygous) or two different allelomorphs (heterozygous) for a gene. For example, if an organism has two brown allelomorphs for eye color, its genotype is homozygous brown. If it has one brown and one blue allelomorph, its genotype is heterozygous brown-blue.
Allelomorphs and Phenotype
The observable physical or biochemical characteristics of an organism are called its phenotype. The phenotype is determined by the interaction of the genotype and the environment. For example, the phenotype for eye color depends on the genotype and the amount of sunlight exposure.
Some allelomorphs are dominant over others, meaning that they mask or override the effect of the other allelomorph in a heterozygous pair. For example, the brown allelomorph for eye color is dominant over the blue allelomorph, so an organism with a heterozygous brown-blue genotype will have a brown eye color phenotype. Some allelomorphs are recessive, meaning that they are only expressed when both allelomorphs in a pair are identical. For example, the blue allelomorph for eye color is recessive, so an organism with a homozygous blue genotype will have a blue eye color phenotype.
Some allelomorphs are codominant, meaning that they are both expressed equally in a heterozygous pair. For example, the A and B allelomorphs for blood type are codominant, so an organism with a heterozygous AB genotype will have an AB blood type phenotype. Some traits are determined by more than two allelomorphs or more than one gene, resulting in multiple phenotypes and complex inheritance patterns.
Conclusion
An allelomorph, or an allele, is a variation of the same gene that may occur at the same locus on a chromosome. Allelomorphs are responsible for the diversity of traits that we observe in living organisms. The combination of allelomorphs that an organism carries for a given gene is called its genotype. The observable characteristics of an organism are called its phenotype, which is determined by the interaction of the genotype and the environment.