What is a polymorphism?
The simultaneous occurrence of two or more versions of a gene in a population. In mitochondrial DNA, it usually refers to different bases at a particular position. The notation “A750G” indicates that there is a polymorphism at position 750, with “A” in one version and “G” in another. The frequency of the rarest form of the polymorphism is higher than can be maintained by recurrent mutation. More information. Two random people of European descent will have roughly 30 to 40 polymorphic sites that distinguish their mitochondrial genomes. The polymorphisms can be use to group people into groups with common ancestry, called haplogroups, or, less formally, maternal clans.
Polymorphisms are sequence variations in DNA.7 The simplest type of sequence polymorphism is a Single Nucleotide Polymorphism (or SNP, pronounced “snip”), in which a nucleotide in a base pair is substituted for another nucleotide. When this happens, a nucleotide sequence that might look like AACCAAG instead looks like AACTAAG. Each of the two variations of the gene is called an allele.8 Polymorphisms involve alleles that occur in at least one percent of the population. Slideshow: Polymorphism and Mutations What is a mutation? Most people use the term “mutation” to refer to a harmful genetic variation associated with a specific human disease or disorder. Like a polymorphism, a mutation is a variation in DNA sequence – but mutations are rarer, occurring in less than one percent of the population. Mutations cause cells to produce proteins that function abnormally or are non-functional, which can result in disease or adverse reaction to medicine. What is a genome?
Programming using parametric polymorphism is called generic programming, particularly in the object-oriented community. Advocates of object-oriented programming often cite polymorphism as one of the major benefits of that paradigm over others. Advocates of functional programming reject this claim on the grounds that the notion of parametric polymorphism is so deeply ingrained in many statically typed functional programming languages that most programmers simply take it for granted. However, the rise in popularity of object-oriented programming languages did contribute greatly to awareness and use of polymorphism in the mainstream programming community.
