Gene MutationsGene Mutations

Mutations: a mistake made in Mutations: a mistake made in DNADNA

Gene MutationGene Mutation

• Mutation that changes one geneMutation that changes one gene

• The Rat Hid And The Cat Sat And Got FatThe Rat Hid And The Cat Sat And Got Fat

• Substitute a letter in the sentence makes it Substitute a letter in the sentence makes it meaninglessmeaningless

• The The PPat Hid And The Cat Sat And Got Fatat Hid And The Cat Sat And Got Fat

• Adding or deleting a letter is worse because Adding or deleting a letter is worse because ALL words changeALL words change

• The Rat HiThe Rat Hix x Dan Dth Eca Tsa Tan Dgo Tfa TDan Dth Eca Tsa Tan Dgo Tfa T

• The RaThe Rah h Ida Ndt Hec Ats Atat Ndg Otf AtIda Ndt Hec Ats Atat Ndg Otf At

Consequences of mutationsConsequences of mutations

• Amino acids make polypeptides Amino acids make polypeptides which makes proteinswhich makes proteins

• If one or more amino acids are If one or more amino acids are wrong, then the organism can’t build wrong, then the organism can’t build the correct proteinsthe correct proteins

Gene Mutations: 2 typesGene Mutations: 2 types

• 1. Point mutations: mutation that 1. Point mutations: mutation that occur at one point in the sequenceoccur at one point in the sequence

• 2. Frameshift mutations: mutation 2. Frameshift mutations: mutation that shifts how all the codons are that shifts how all the codons are readread

A G U C G G U G U A A GA G U C G G U G U A A G

• A G U C G G U A G U C G G U U U G U A A G G U A A G

insertioninsertion

Frameshift MutationFrameshift Mutation

A G U C G G U G U A A GA G U C G G U G U A A G

• A G U C G G A G U C G G GG U A A G U A A G

DeletionDeletion

Frameshift MutationFrameshift Mutation

A G U C G G U G U A A GA G U C G G U G U A A G

• A G U C G G U A G U C G G U U U U A A GU A A G

SubstitutionSubstitution

Point MutationPoint Mutation

Chromosome MutationsChromosome Mutations

• Structure or number of chromosomes Structure or number of chromosomes changechange

DuplicationDuplication

• Broken part can reattach to a sister Broken part can reattach to a sister chromatidchromatid

• Normal chromosomeNormal chromosome

• ABCDE FGHABCDE FGH

• Duplication of C and DDuplication of C and D

• ABCDABCDCDCDE FGHE FGH

DeletionDeletion

• Normal chromosomeNormal chromosome

• ABCDE FGHABCDE FGH

• Deletion of C and DDeletion of C and D

• ABE FGHABE FGH

InversionInversion

• Broken part reattaches backwardsBroken part reattaches backwards

• Normal chromosomeNormal chromosome

• ABCDE FGHABCDE FGH

• Inversion of B and CInversion of B and C

• AACBCBDE FGHDE FGH

TranslocationTranslocation

• Broken part attaches to ANOTHER Broken part attaches to ANOTHER chromosomechromosome

• Normal chromosomeNormal chromosome

• ABCDE FGHABCDE FGH

• CDCDM NOPQRM NOPQR

When do mutations occur?When do mutations occur?

• MitosisMitosis

• MeiosisMeiosis

MitosisMitosis

• Occurs only in the individual and Occurs only in the individual and does NOT get passed on to offspringdoes NOT get passed on to offspring

• Example: cancerExample: cancer

• Common reasons for mutations: UV Common reasons for mutations: UV radiation from the sun, tanning radiation from the sun, tanning booths, x-rays, tobacco, asbestos, booths, x-rays, tobacco, asbestos, benzene, chemical pesticidesbenzene, chemical pesticides

MeiosisMeiosis

• Mutations that are passed on to Mutations that are passed on to offspringoffspring

• Examples:Examples:

• Sickle cell disease: substitutionSickle cell disease: substitution

• Tay-Sachs: frameshiftTay-Sachs: frameshift

• Down syndrome: chromosome Down syndrome: chromosome mutation on number 21mutation on number 21