mutations

• mutation


  change in sequence of base pairs in a DNA molecule which may result in altered polypeptide

  most mutations have little effect due to degenerate nature
• insertion

  • a nucleotide/base randomly inserted
  • changes the amino acid which would have been coded for by original base triplet
  • can have knock on effect- change codons further on in sequence
  • can change amino acid sequence produced and ability of polypeptide to function
• deletion

  • a nucleotide is randomly deleted from DNA sequence
  • changes that codon and also every group of triplets further down
  • changes amino acid sequence
• substitution

  • base in DNA sequence randomly swapped for a different base
  • only changes the amino acid for triplet where mutation occured- no knock on effect

  -doesnt alter amino acid sequence due to degenerate nature

  -alters single amino acid in polypeptide chain

  -creates a premature stop codon- affecing final protein structure and function
• duplication

  • production of 1 or more copies of a gene or region of chromosome
  • 2 copies appear on same chromosome
  • original version of gene still intact thus mutation not harmful
  • gene duplication= way evolution occurs(random mutations in pop)