One allele for every gene in an organism is inherited from each of that organism’s parents. In some cases, both parents provide the same allele of a given gene, and the offspring is referred to as homozygous (“homo” meaning “same”) for that allele.
Where do the two alleles for a trait come from?
An individual inherits two alleles for each gene, one from each parent. If the two alleles are the same, the individual is homozygous for that gene. If the alleles are different, the individual is heterozygous.
Why do traits have two alleles?
There is more than one variant for many genes, slight differences in the copies of the gene that change the trait that the individual expresses. The variants of the gene are known as alleles and individuals who are diploid for that trait have two alleles, getting one copy of their genome from each parent.
When an organism has two identical alleles for a trait?
An organism in which the two copies of the gene are identical — that is, have the same allele — is called homozygous for that gene. An organism which has two different alleles of the gene is called heterozygous.
What is the best definition of allele?
Allele, also called allelomorph, any one of two or more genes that may occur alternatively at a given site (locus) on a chromosome. Alleles may occur in pairs, or there may be multiple alleles affecting the expression (phenotype) of a particular trait.
What genes have more than two alleles?
Alleles are the pairs of genes occupying a specific spot called locus on a chromosome. Typically, there are only two alleles for a gene in a diploid organism. When there is a gene existing in more than two allelic forms, this condition is referred to as multiple allelism.
What human traits have multiple alleles?
The best characterized example of multiple alleles in humans is the ABO blood groups, discussed in the Non-Mendelian Inheritance concept. Other human traits determined by multiple alleles would be hair color, hair texture, eye color, built, physical structures, etc.
What is a hidden trait called?
An organism receives two genes for each trait, one from each parent. … The trait of the weaker gene is “hidden” or does not show up and is called the recessive gene.
What are the traits of an organism called?
The observable traits expressed by an organism are referred to as its phenotype. An organism’s underlying genetic makeup, consisting of both physically visible and non-expressed alleles, is called its genotype.