A gene is a stretch of DNA or RNA that determines a certain trait,Genes mutate and can take two or more alternative forms; an allele is one of these forms of a gene. An allele is one of two or more versions of a gene. An individual inherits two alleles for each gene, one from each parent.
Alleles of a gene. Let's return to the pea plant and say that the red allele for flower color is dominant to the white allele for flower color. We can equivalently say that the white allele for flower color is recessive to the red flower-color allele. This means that if a pea plant has two red alleles, its flowers will be red. If it has to white alleles, its flowers will be white. And, if it has a red allele and a white allele, its flowers will be red. If the red and white alleles are codominant, then a plant with to red alleles will have red flowers, a plant with two white alleles will have white flowers, and a plant with a red allele and a white allele will have pink glowers. Now, let's turn to a couple examples of dominant and recessive alleles in humans. 1 An interesting difference between alleles and genes is that alleles produce opposite phenotypes that are contrasting by nature. 2  When the two partners of a gene are homogeneous in nature, they are called homozygous. 3  However, if the pair consists of different alleles, they are called heterozygous. Gene vs Allele. A gene is a part of the DNA. Alleles on the other hand refer to different versions of the same gene. There are other more subtle differences between the two and this is what we are going to explore on this page: Diploid organisms have one copy of each gene (and, therefore, one allele) on each chromosome. If both alleles are the same, they and the organism are homozygous with respect to that gene. If the alleles are different, they and the organism are heterozygous with respect to that gene. The word allele is a short form of allelomorph (other form), which was used in the early days of genetics to describe variant forms of a gene detected as different phenotypes. Alleles contribute to the organism's phenotype, which is the outward appearance of the organism. Some alleles are dominant or recessive. When an organism is heterozygous at a specific locus and carries one dominant and one recessive allele, the organism will express the dominant phenotype. Alleles can also refer to minor DNA sequence variations between alleles that do not necessarily influence the gene's phenotype. 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.  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. When an organism is heterozygous at a specific locus and carries one dominant and one recessive allele, the organism will express the dominant phenotype. Alleles can also refer to minor DNA sequence variations between alleles that do not necessarily influence the gene's A gene is a stretch of DNA or RNA that determines a certain trait. Genes mutate and can take two or more alternative forms; an allele is one of these forms of a gene. For example, the gene for eye color has several variations (alleles) such as an allele for blue eye color or an allele for brown eyes. An allele is found at a fixed spot on a chromosome. Chromosomes occur in pairs so organisms have two alleles for each gene — one allele in each chromosome in the pair. Alleles may be dominant or recessive. A dominant allele is one that will always be expressed if present. For example, the allele for Huntington’s disease is dominant, so if an individual inherits an allele for Huntington’s from only one of the parents, they will have the disease. By Regina Bailey. Definition: An allele is an alternative form of a gene (one member of a pair) that is located at a specific position on a specific chromosome. These DNA codings determine distinct traits that can be passed on from parents to offspring through sexual reproduction. When the alleles of a pair are heterozygous, one may be dominant and the other recessive. The dominant allele is expressed and the recessive allele is masked. Best Answer: An allele is a DNA sequence that codes for a gene. In simpler terms, it is a given form for a gene. Two alleles for the same gene might be two alleles for blood type: A (for blood type A) and B (for blood type B). Humans receive two alleles for each gene: one from the mother and one from the father. 
http://www.stat.washington.edu/thompson/Genetics/1.2_alleles.html http://www.differencebetween.net/science/difference-between-gene-and-allele/ https://en.wikipedia.org/wiki/Allele http://www.nature.com/scitable/definition/allele-48 http://www.ghr.nlm.nih.gov/glossary=allele http://www.nature.com/scitable/definition/allele-48 http://www.diffen.com/difference/Allele_vs_Gene http://biology.about.com/od/geneticsglossary/g/alleles.htm https://answers.yahoo.com/question/index?qid=20070312163951AAYiy0j
what is an alleles of a gene