Biology - Gene mutations

substitution mutations

mutation that occurs when a nucleotide base is randomly swapped for a different base, causes single nucleotide polymorphisms

insertion mutation

new base is randomly inserted, knock on effect: frameshift mutation

deletion mutation

base is randomly deleted, knock on effect, frameshift mutation

causes of mutation

• radiation. eg. high energy radiation such as UV light or ionising radiation like x-rays

• chemical substances. eg. tobacco smoke, mustard gas

• random

randomness of mutations

some locations are more likely to mutate than others.

eg. uncoiled DNA has higher risk than tightly coiled because it is more exposed

mutation hot spots

non coding regions

effect of SNP

1- silent mutations, don’t affect amino acid sequence

2 - mis sense mutations, alter single amino acid

3 - nonsense mutations, premature stop codon

germ line

cells involved in inheritance of genetic information

mutation in somatic cells

not inherited but can cause cancer.

cancer starts when mutation occurs in genes that control cell division.

if mutated gene is the one that causes cancer: oncogene

gene knockout

• finding function of gene by removing it or making it unusable in the genome

• classed as a genetic engineering technique

new gene editing technique

CRISPR

• clustered regularly interspaced short palindromic repeats

• uses natural deffense bacteria evolved to cut DNA at specific point determined by a guide RNA attached to enzyme cas9

conserved sequence

section of DNA/RNA with minimal mutations. eg. proteins involved in cellular respiration or transcription and translation