write a short note on allele
Answers
Answer:
You can make it rather short according to your will...
Explanation:
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. If the paired alleles are the same, the organism is said to be homozygous for that trait; if they are different, the organism is heterozygous. A dominant allele will override the traits of a recessive allele in a heterozygous pairing. In some traits, however, alleles may be codominant—i.e., neither acts as dominant or recessive. An example is the human ABO blood system; persons with type AB blood have one allele for A and one for B. (Persons with neither are type O.) See also dominance; recessiveness.
Most traits are determined by more than two alleles. Multiple forms of the allele may exist, though only two will attach to the designated gene site during meiosis. Also, some traits are controlled by two or more gene sites. Both possibilities multiply the number of alleles involved. All genetic traits are the result of the interactions of alleles. Mutation, crossing over, and environmental conditions selectively change the frequency of phenotypes (and thus their alleles) within a population.
Answer:
An allele is specific variation of a gene. Bacteria, because they have a single ring of DNA, have one allele per gene per organism. In sexually reproducing organisms, each parent gives an allele for each gene, giving the offspring two alleles per gene. Because alleles are just variants of specific genes, different alleles are found on the same location on the chromosomes of different individuals.