mutations

• translocation

  where a section breaks off one chromosome and becomes attached to another non-homologous chromosome
• inversion

  where a section of the chromosome is rotated 180 degrees so that the order of genes is reversed
• duplication

  where an identical section of chromosome is inserted into a chromosome, resulting in there being a section being repeated
• deletion (chromosomal)

  where a section of the chromosome is lost completely
• horizontal gene transfer - prokaryotes
• vertical gene transfer - eukaryotes and prokaryotes
• mutation - a change in the DNA that can result in no protein or an altered protein being expressed
• non coding regions regulate transcription
• frameshift - if the number of nucleotides added or removed in a deletion or insertion is not a multiple of 3 frameshift occurs. this means all amino acids after the point of mutation are changed.
• misense - a codon of gene is altered so that a different amino acid is coded for
• nonsense - a codon of a gene is altered to create a STOP codon, causing protein synthesis to stop prematurley
• splice site

  if the substitution happens at an mRNA splice site then one or more introns may be left in the modified mRNA and some exons may not be included in the mature transcript
• why are duplications important in evolution?

  Beneficial mutations can occur in one of the copies of the gene

  The other gene can still be expressed to produce its protein
• results of substitution

  • missense
  • non sense
  • splice site