Alleles are different forms of the same gene, usually one dominant and one recessive. Each are genetically different and will give rise to different phenotypes, or physical characteristics. For example, the gene for eye color has a dominant allele with brown as the phenotype and a reccessive allele with blue as the phenotype. Some genes have more than two forms, but only two will ever be expressed together at the same time, one from each parent.
2006-12-08 00:05:01
·
answer #1
·
answered by Empress Sky 2
·
0⤊
0⤋
In genetics, an allele (pronounced al-eel) is any one of a number of viable DNA codings occupying a given locus (position) on a chromosome. Usually alleles are DNA (deoxyribonucleic acid) sequences that code for a gene, but sometimes the term is used to refer to a non-gene sequence. An individual's genotype for that gene is the set of alleles it happens to possess. In a diploid organism, one that has two copies of each chromosome, two alleles make up the individual's genotype.
An example is the gene for blossom color in many species of flower—a single gene controls the color of the petals, but there may be several different versions (or alleles) of the gene. One version might result in red petals, while another might result in white petals. The resulting color of an individual flower will depend on which two alleles it possesses for the gene and how the two interact.
2006-12-08 21:38:25
·
answer #2
·
answered by Aditya N 2
·
0⤊
0⤋
In genetics, an allele (pronounced al-eel) is any one of a number of viable DNA codings occupying a given locus (position) on a chromosome. Usually alleles are DNA sequences that code for a gene, but sometimes the term is used to refer to a non-gene sequence. An individual's genotype for that gene is the set of alleles it happens to possess. In a diploid organism, one that has two copies of each chromosome, two alleles make up the individual's genotype.
An example is the gene for blossom color in many species of flower—a single gene controls the color of the petals, but there may be several different versions (or alleles) of the gene. One version might result in red petals, while another might result in white petals. The resulting color of an individual flower will depend on which two alleles it possesses for the gene and how the two interact
Diploid organisms, such as humans, have paired homologous chromosomes in their somatic cells, and these contain two copies of each 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. Phenotypes (the expressed characteristics) associated with a certain allele can sometimes be dominant or recessive, but often they are neither. A dominant phenotype will be expressed when at least one allele of its associated type is present, whereas a recessive phenotype will only be expressed when both alleles are of its associated type.
However, there are exceptions to the way heterozygotes express themselves in the phenotype. One exception is incomplete dominance (sometimes called blending inheritance) when alleles blend their traits in the phenotype. An example of this would be seen if, when crossing Antirrhinums — flowers with incompletely dominant "red" and "white" alleles for petal color — the resulting offspring had pink petals. Another exception is co-dominance, where both alleles are active and both traits are expressed at the same time; for example, both red and white petals in the same bloom or red and white flowers on the same plant. Codominance is also apparent in human blood types. A person with one "A" blood type allele and one "B" blood type allele would have a blood type of "AB".
A wild type allele is an allele which is considered to be "normal" for the organism in question, as opposed to a mutant allele which is usually a relatively new modification
2006-12-11 06:43:49
·
answer #3
·
answered by No matter what happens i ll... 2
·
0⤊
0⤋
"In genetics, an allele (pronounced al-eel) is any one of a number of viable DNA codings occupying a given locus (position) on a chromosome. Usually alleles are DNA (deoxyribonucleic acid) sequences that code for a gene, but sometimes the term is used to refer to a non-gene sequence. An individual's genotype for that gene is the set of alleles it happens to possess. In a diploid organism, one that has two copies of each chromosome, two alleles make up the individual's genotype."
This, and more, from Wikipedia, the free, online encyclopedia at:
http://en.wikipedia.org/wiki/Alleles
Hope this helps!
2006-12-08 08:16:36
·
answer #4
·
answered by cfpops 5
·
0⤊
0⤋
Two alleles make up one gene.That means allele is basic structure of any given gene.
2006-12-08 07:38:53
·
answer #5
·
answered by chanukyagv 3
·
0⤊
0⤋
alleles can be related to Punnet squares, since they are used as alternates of how a gene may turn out.
there is homozygous, which is when the alleles are the same letter(example:DD)
hetrozygous is when they are different(example:Dd)
2006-12-08 10:09:05
·
answer #6
·
answered by ipodlady231 7
·
0⤊
0⤋