Gene Mutations
Any change tooneor more any rearrangement of the
nucleotidebases or bases
substitution
Nucleotide in a sectionof a DNA molecule is replaced byanother with a differentbase
couldresult in formation of a stop codon
Formationof a codoncodingforanother aminoacid
Formation of a differentcodon coding for thesame aminoacid degenerate
Deletion
Lossof a nucleotidebase
All codon afterdeletionwould beaffected as frameshift occured
Addition
Extrabase becomes inserted in thesequence
All codon afteradditionwould beaffected as frameshift occured
Duplication
One or more base is repeated
Frameshift to the right
Inversion
Agroup of bases become separatedfromtheDNA sequence andrejoin atthe same
position butin reverse order
Affects polypeptide as therewillbe differentamino acids
Translocation
A group of bases separates from the DNAsequence on onechromosome andbecome
inserted into DNAsequence of differentchromosome
Significant effects on gene expression leading to an abnormal phenotype
, Causes of Mutations
Mutations can arisespontaneously during DNA replication without externalinfluence
MutagenicAgents
HighEnergyIonising Radiation Disrupts theDNAstructure
Chemicals No2 Mayalter DNA or interfere withtranscription
stemcellsandTotipotency
Totipotentcells Candivideandproduceany type of body cell
During all specialisation onlysome of thegenes are expressed so onlysomeof theDNA is
translated intoproteins Therefore cells are specialised to outparticularfunctions as if the
carry
arestill making otherproteins it would be wastefuland a wasteof energy
Preventing transcription and translation to stop ancessay proteinsfrom beingproduced
Stemcells
Undifferentiated dividingcells thatoccur in adultanimal tissues and need to be constant
replaced
Sources
EmbryonicStemCells Differentiateintoany typeofcell in theinitialstage ofdevelopment
UmbilicalCordBloodStemcells similar to adultstemcells
PlacentalStemCells Develop into specific types ofcell
Adultstemcells specificto particular tissueor organ whichtheyproduce the cells to
maintain andrepair tissues throughout organism's life
Any change tooneor more any rearrangement of the
nucleotidebases or bases
substitution
Nucleotide in a sectionof a DNA molecule is replaced byanother with a differentbase
couldresult in formation of a stop codon
Formationof a codoncodingforanother aminoacid
Formation of a differentcodon coding for thesame aminoacid degenerate
Deletion
Lossof a nucleotidebase
All codon afterdeletionwould beaffected as frameshift occured
Addition
Extrabase becomes inserted in thesequence
All codon afteradditionwould beaffected as frameshift occured
Duplication
One or more base is repeated
Frameshift to the right
Inversion
Agroup of bases become separatedfromtheDNA sequence andrejoin atthe same
position butin reverse order
Affects polypeptide as therewillbe differentamino acids
Translocation
A group of bases separates from the DNAsequence on onechromosome andbecome
inserted into DNAsequence of differentchromosome
Significant effects on gene expression leading to an abnormal phenotype
, Causes of Mutations
Mutations can arisespontaneously during DNA replication without externalinfluence
MutagenicAgents
HighEnergyIonising Radiation Disrupts theDNAstructure
Chemicals No2 Mayalter DNA or interfere withtranscription
stemcellsandTotipotency
Totipotentcells Candivideandproduceany type of body cell
During all specialisation onlysome of thegenes are expressed so onlysomeof theDNA is
translated intoproteins Therefore cells are specialised to outparticularfunctions as if the
carry
arestill making otherproteins it would be wastefuland a wasteof energy
Preventing transcription and translation to stop ancessay proteinsfrom beingproduced
Stemcells
Undifferentiated dividingcells thatoccur in adultanimal tissues and need to be constant
replaced
Sources
EmbryonicStemCells Differentiateintoany typeofcell in theinitialstage ofdevelopment
UmbilicalCordBloodStemcells similar to adultstemcells
PlacentalStemCells Develop into specific types ofcell
Adultstemcells specificto particular tissueor organ whichtheyproduce the cells to
maintain andrepair tissues throughout organism's life
