mutations in non coding dna

• • Affect regulatory regions controlling gene expression and therefore impact cell functioning
• • Mutations in introns no impact on final polypeptide unless occurs in splice sit which are sequences at junctions between introns and exons→ mutation may cause intron to be skipped and left in mRNA or exon may be removed resulting in incorrect mature mRNA sequence and resulting polypeptide
• • Non coding DNA in intergenic regions have important functions:
  • Promoter region priming genes to switch on
  • Terminator (silencer) regions shutting down genes and switching them off
  • Enhances increasing expression of gene
• • Mutations in these regions can impact expression of genes leading to development and congenital abnormials e.g congenital heart defect