Different varieties of the same gene are called

Question

Prepp Team · Accepted Answer

Understanding Genes and Their Varieties: Alleles

Genes are fundamental units of heredity, passed from parents to offspring. They contain the instructions for building and maintaining an organism. Each gene occupies a specific position, called a locus, on a chromosome.

While a species has the same set of genes, these genes can exist in different forms or varieties. These different forms arise primarily through mutations.

What are Alleles?

The different varieties or forms of the same gene are specifically called alleles. For example, a gene for flower color might have one allele for red color and another allele for white color. An individual inherits two alleles for each gene, one from each parent. These two alleles can be the same or different.

Analyzing the Options:

Let's look at the provided options to determine the correct term for different varieties of the same gene:

Genotypes: A genotype refers to the genetic makeup of an organism, the specific combination of alleles it possesses for one or more genes. It is not the different varieties of a single gene itself.
Sib pairs: This term refers to a pair of siblings (brothers or sisters). It is related to individuals and family relationships, not the forms of a gene.
Alleles: As discussed, alleles are the different forms or variants of a specific gene. This aligns directly with the question.
Isomers: This is a term used in chemistry to describe molecules that have the same chemical formula but different structural arrangements. It has no relevance in genetics concerning gene varieties.

Based on the analysis, the term that describes different varieties of the same gene is alleles.

Detailed Concepts Related to Genes and Alleles

Understanding alleles is crucial in genetics. Here are some related concepts:

Homozygous: An individual is homozygous for a gene if they have two identical alleles for that gene (e.g., two alleles for red flower color).
Heterozygous: An individual is heterozygous for a gene if they have two different alleles for that gene (e.g., one allele for red flower color and one allele for white flower color).
Dominant and Recessive Alleles: In heterozygous individuals, one allele (the dominant allele) might mask the expression of the other allele (the recessive allele). The trait expressed is determined by the interaction of the alleles.
Phenotype: The observable physical or biochemical characteristics of an organism, resulting from the interaction of its genotype and the environment.

Consider a simple example:

Gene	Alleles	Genotypes	Possible Phenotypes (assuming simple dominance)
Flower Color (let's use 'R' for red, 'r' for white)	R (red allele), r (white allele)	RR, Rr, rr	Red (from RR, Rr), White (from rr)

Revision Table: Key Terms in Genetics

Term	Definition
Gene	A unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring.
Allele	One of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.
Locus	The specific physical location of a gene or other DNA sequence on a chromosome.
Genotype	The genetic constitution of an individual organism.
Phenotype	The set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.

Additional Information: Allele Origin and Variation

Alleles arise primarily through mutations, which are changes in the DNA sequence of a gene. These mutations can be spontaneous or induced by environmental factors. If a mutation occurs in the germ cells (sperm or egg cells), it can be passed on to subsequent generations, creating a new allele in the population.

The existence of different alleles for a gene within a population contributes to genetic variation, which is essential for evolution and adaptation. Studying alleles helps geneticists understand how traits are inherited and how genetic disorders occur.