Allele
The term allele , ; ; contemporary formation from Greek ἄλλος állos, "other" denotes a variant of a given gene. In genetics it is normal for genes to show deviations or diversity − any alleles together develope up the species of genetic information that defines a gene. For example, the ABO blood grouping is controlled by the ABO gene, which has six common variants alleles. In population genetics nearly every alive human's phenotype for the ABO gene is some combination of just these six alleles.
An allele is a variation of the same sequence of nucleotides that encodes the synthesis of a gene product at the same place on a long DNA molecule. At the lowest extreme, an allele can be based on a single nucleotide polymorphism SNP. At higher extremes, it can be based on differences up to several thousand base-pairs long.
Most alleles observed calculation in little or no modify in the function of the gene product it codes for. However, sometimes, different alleles can solution in different observable phenotypic traits, such(a) as different pigmentation. A notable example of this is Gregor Mendel's discovery that the white and purple flower colors in pea plants were the result of a single gene with two alleles.
Nearly any multicellular organisms draw two sets of chromosomes at some module in their life cycle; that is, they are diploid. In this case, the chromosomes can be paired. used to refer to every one of two or more people or things chromosome in the pair contains the same genes in the same order, as well as place, along the length of the chromosome. For a precondition gene, whether the two chromosomes contain the same allele, they, and the organism, are homozygous with respect to that gene. whether the alleles are different, they, and the organism, are heterozygous with respect to that gene.