An allele is a variant form of a gene. Some genes have a variety of different forms, which are located at the same position, or genetic locus, on a chromosome. Alleles contribute to the organism’s phenotype, which is the outward appearance of the organism. Some alleles are dominant or recessive.

Genes come in different varieties, called alleles. However, an allele that is hidden, or not expressed by an organism, can still be passed on to that organism’s offspring and expressed in a later generation.

– The various specific forms of a gene are allele. Pairs of heritable factors are alternative forms of the same gene. These different forms are called alleles. – One member of a pair (or any of the series) of genes occupying a specific spot on a chromosome (called locus) that controls the same trait.

(jeen) The basic unit of heredity that occupies a specific location on a chromosome. Each consists of nucleotides arranged in a linear manner. Most genes code for a specific protein or segment of protein leading to a particular characteristic or function.

Therefore, a broad, modern working definition of a gene is any discrete locus of heritable, genomic sequence which affect an organism’s traits by being expressed as a functional product or by regulation of gene expression.

A gene is the basic physical and functional unit of heredity. Genes are made up of DNA. Some genes act as instructions to make molecules called proteins. Alleles are forms of the same gene with small differences in their sequence of DNA bases.

Genotype is the collection of genes responsible for the various genetic traits of a given organism. Genotype refers specifically to the genes, not the traits; that is, the raw information in an organism’s DNA. An allele can be made up of two dominant genes, a dominant and a recessive gene, or two recessive genes.