MutationMutationChanging your Changing your genesgenes

Mutation definedMutation defined A A MutationMutation occurs occurs

when when a DNA genea DNA gene is is damageddamaged or or changedchanged in such a in such a way as to way as to alteralter the the genetic messagegenetic message carried by that gene. carried by that gene.

Example to right the enzyme that is Example to right the enzyme that is catalyzing the production of flower catalyzing the production of flower color pigment has been altered in color pigment has been altered in such a way it no longer catalyzes such a way it no longer catalyzes the production of the red pigment. the production of the red pigment.

Types of MutationTypes of Mutation

Gene mutationGene mutation

Chromosome Chromosome mutationmutation

Gene MutationGene Mutation Gene mutation Gene mutation

– most commonmost common– within a genewithin a gene– one or more points changedone or more points changed– Base(s) can beBase(s) can be

SubstitutedSubstituted DeletedDeleted AddedAdded

– ResultResult: : proteinprotein with with 11 or or more errorsmore errors

Gene Mutation an AnalogyGene Mutation an Analogy A sentence with three letter words, A sentence with three letter words,

like the triplet codes in DNA.like the triplet codes in DNA.– ““The fat cat ate the ratThe fat cat ate the rat” makes sense” makes sense

Gene mutation Gene mutation substitutionsubstitution– Substitute an ‘Substitute an ‘aa’ for an ‘’ for an ‘oo’.’.

– ““The fat cThe fat coot ate the ratt ate the rat” nonsense, but ” nonsense, but only one word affectedonly one word affected

– ResultResult: : ProteinProtein maymay still be able to still be able to functionfunction

Gene Mutation an Analogy Gene Mutation an Analogy continuedcontinued

– ““The fat cat ate the ratThe fat cat ate the rat” makes sense” makes sense Gene mutation Gene mutation deletiondeletion

– Remove the first ‘Remove the first ‘aa’.’.– ““The The ftc ata tet her atftc ata tet her at” nonsense, and ” nonsense, and

many words affected.many words affected.– ResultResult: : ProteinProtein mostmost likelylikely will will notnot

functionfunction

How would an How would an addition/insertionaddition/insertion affect the affect the resulting amino acids?resulting amino acids?

Chromosomal MutationsChromosomal Mutations Change in Change in

structurestructure of an of an entire chromosomeentire chromosome

oror

Change in Change in chromosome chromosome numbernumber

Chromosomal MutationsChromosomal Mutations continuedcontinued

Changes in Changes in chromosomal structurechromosomal structure – A chromosome can become tangled A chromosome can become tangled

during cell division thus rearranging the during cell division thus rearranging the segmentssegments

– Five possibilities can happenFive possibilities can happen TranslocationTranslocation InversionInversion DeletionDeletion DuplicationDuplication AdditionAddition

Chromosomal structureChromosomal structure

TranslocationTranslocation– SegmentSegment of one of one

chromosome is chromosome is transferredtransferred to to anotheranother

Chromosomal structureChromosomal structure

InversionInversion– SegmentSegment is is rotatedrotated

so the so the orderorder of the of the genesgenes is is reversedreversed

Chromosomal structureChromosomal structure

DeletionDeletion– A A segmentsegment breaks breaks

offoff so so genesgenes are are lostlost

Chromosomal structureChromosomal structure

DuplicationDuplication– A A batchbatch of of genesgenes

are are duplicatedduplicated so so now have now have doubledouble of of these these genesgenes

Chromosomal structureChromosomal structure

AdditionAddition– RepetitionRepetition of of genesgenes on a on a homologuehomologue

Chromosomal MutationsChromosomal Mutations continuedcontinued

Change in Change in chromosomechromosome numbernumber– Two typesTwo types

PolyploidyPolyploidy NondisjunctionNondisjunction

Chromosome Chromosome numbernumber PolyploidyPolyploidy

– Mostly in plantsMostly in plants– Multiples of ‘n’Multiples of ‘n’

(3n, 4n, 5n)(3n, 4n, 5n)– ImproperImproper

separationseparation during during meiosismeiosis

– Often yields larger Often yields larger fruitfruit

Chromosome Chromosome numbernumber NondisjunctionNondisjunction

– MisplacementMisplacement of a of a whole chromosomewhole chromosome during during meiosismeiosis

– ResultsResults TrisomyTrisomy or or 2n +12n +1

ex: Down’s Syndromeex: Down’s Syndrome

MonosomyMonosomy or or 2n -12n -1ex: Turner’s ex: Turner’s SyndromeSyndrome