How many of the following statements regarding mutations are correct ?
(i) Mutation is a phenomenon which results in alteration of DNA sequences and consequently results in changes in the genotype and phenotype of an organism.
(ii) Gene/point mutation is responsible for Sickle-cell anemia.
(iii) Chromosomal mutation is responsible for Down’s syndrome.
(iv) In addition to recombination, mutation is another phenomenon that leads to variation of DNA.
(v) Chromosomal aberrations are commonly observed in cancer cells.
(vi) Deletion of base pairs of DNA causes frame-shift mutations, but not by insertion of a base pair.