<prompt> True about polymorphism is: PGI Dec 2006Single locus - multiple normal allelesSingle locus - multiple abnormal allelesSingle phenotype: single Iocus-multiple normal alleles multiple abnormal allelesSingle phenotype: Single !ocus-multiple abnormal alleles.  <response>: Ans: D Single phenotype, single locus, - multiple allele Polymorphisms is single phenotype, single locus mu Itipie normal allelerPolymorphisms Clinically ,iarmless variationQ of DNA sequence Normal variation in DNA sequence that have frequency of at least 1. Usally, they dont result in a perceptible phenotype i.e,phenotype sameQ.They constitutes: Single base-pair substitution often Deletions and insertionsThey dont alter protein coding sequence probaly due to degeneracy of genetic code although it is possible that it might alter mRNA stability, translation or aminoacid sequences. 