genetic mutations
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Genetic MutationsGenetic Mutations
Genetic mutationsGenetic mutations
Not all are harmfulNot all are harmful Most cause little/no changeMost cause little/no change Have to be reproductive cell Have to be reproductive cell
mutations to repeat in future mutations to repeat in future generationsgenerations
Somatic mutations not inheritableSomatic mutations not inheritable
What are mutations?What are mutations?
Changes in the genetic Changes in the genetic sequence that affect sequence that affect genetic informationgenetic information
Two typesTwo types• Gene mutationsGene mutations• Chromosomal mutationsChromosomal mutations
Rust’s Disease
Normal Human Karyotype
Examples of mutationsExamples of mutations
Changes in the DNA sequence that Changes in the DNA sequence that affect genetic informationaffect genetic information• Normal:Normal:
Thesunwashotbuttheoldmandidnotgethishat.Thesunwashotbuttheoldmandidnotgethishat.The sun was hot but the old man did not get his hat.The sun was hot but the old man did not get his hat.
• Translation changed in ribosome:Translation changed in ribosome:t hes unw ash otb utt heo ldm and idn otg ish at.t hes unw ash otb utt heo ldm and idn otg ish at.
• Missing letter or base:Missing letter or base:the sun wsh otb utt heo ldm and idn otg ish at.the sun wsh otb utt heo ldm and idn otg ish at.
How do mutations How do mutations happen?happen?
Environmental Environmental agentsagents• UV light, chemicals, UV light, chemicals,
radiationradiation
Meiosis Meiosis • more/less more/less
chromosomeschromosomes
Mistakes in DNA Mistakes in DNA replicationreplication
What happens when there is a What happens when there is a mutation?mutation?
The mistake can cause the cell to make an incorrect The mistake can cause the cell to make an incorrect proteinprotein• see a see a different phenotypedifferent phenotype than normal ex. White Buffalo than normal ex. White Buffalo
If the mutation occurs in a single type of cell, If the mutation occurs in a single type of cell, • it will affect it will affect only the cell that carries itonly the cell that carries it ex. Skin cells ex. Skin cells
If the mutation occurs in a sex cell, If the mutation occurs in a sex cell, • it can be it can be passed to the offspring and affect their phenotypepassed to the offspring and affect their phenotype
Mutations can introduce Mutations can introduce genetic variationgenetic variation• the change can be the change can be helpful, harmful or neitherhelpful, harmful or neither
Where do they happen?Where do they happen?
Gene MutationsGene Mutations• replicationreplication• transcriptiontranscription• translationtranslation
Chromosome Structural Changes Chromosome Structural Changes • MitosisMitosis• MeiosisMeiosis
Gene MutationsGene Mutations
Point MutationsPoint Mutations• involve one nucleotide involve one nucleotide • single point in a DNA sequencesingle point in a DNA sequence
Substitute one base for anotherSubstitute one base for another
Gene MutationsGene Mutations
Frameshift Frameshift • insertion or deletion of a baseinsertion or deletion of a base• shifts entire sequence for translationshifts entire sequence for translation• different group of amino acids different group of amino acids • changes the protein functionchanges the protein function
Review Gene mutationsReview Gene mutations Point mutations – mistakes with 1 nucleotidePoint mutations – mistakes with 1 nucleotide
• Substitution of the wrong nucleotide (nitrogen base) in Substitution of the wrong nucleotide (nitrogen base) in place of correct oneplace of correct one
Frameshift mutations – occur when a nucleotide is either Frameshift mutations – occur when a nucleotide is either inserted or deleted, altering the trios of nitrogen basesinserted or deleted, altering the trios of nitrogen bases• More severe than point mutations because it effects all of More severe than point mutations because it effects all of
the amino acids in the proteinthe amino acids in the protein
Chromosome Structural ChangesChromosome Structural Changes
DeletionDeletion- - loss of all or part of loss of all or part of
chromosomechromosome
- missing genes - missing genes may prove fatalmay prove fatal
DuplicationDuplication- - segment repeatedsegment repeated
- usually harmless- usually harmless
Chromosome Structural ChangesChromosome Structural Changes
InversionInversion- - connection broken & connection broken & sequence reversedsequence reversed- may be fatal- may be fatal
TranslocationTranslocation- non-homologous - non-homologous chromosomes sharing chromosomes sharing or exchanging or exchanging information information
Review Chromosomal Review Chromosomal mutationsmutations
Change in the number or structure Change in the number or structure of the chromosomesof the chromosomes• DeletionDeletion• DuplicationDuplication• InversionInversion• translocationtranslocation
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