Can a gene have one allele?
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. Humans are called diploid organisms because they have two alleles at each genetic locus, with one allele inherited from each parent.
Are alleles always the same form of a gene?
Different versions of the same gene are called alleles. Genes can have two or more possible alleles. Individual humans have two alleles, or versions, of every gene. Because humans have two gene variants for each gene, we are known as diploid organisms.
Why do we have two alleles for each gene?
Since diploid organisms have two copies of each chromosome, they have two of each gene. Since genes come in more than one version, an organism can have two of the same alleles of a gene, or two different alleles. This is important because alleles can be dominant, recessive, or codominant to each other.
What is the maximum number of alleles that a human can have?
It must be remembered that the maximum number of alleles an individual organism can have is equal to its ploidy, i.e., the number of haploid sets it possesses. For diploid organisms like humans, maximum two allelic variants are possible in a single organism.
How can a gene exist in more than one form?
Most genes exist in more than one form that, when expressed, result in different characteristics. In such cases, one allele of the gene produces one color (e.g., red flowers) while another allele of flower color gene may produce another color flower (e.g., white flowers). …
An allele is one of two or more versions of a gene. 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.
How can someone have two different alleles of the same gene?
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.