To demonstrate understanding, after this lesson, To demonstrate understanding, after this lesson, you should be able toyou should be able to

define mutationsdefine mutations explain how mutations occur explain how mutations occur

when – DNA Replication or Meiosis when – DNA Replication or Meiosis how – radiation &mutagenic chemicals how – radiation &mutagenic chemicals

recognize point (N-base) mutations recognize point (N-base) mutations (insertions, deletions and substitutions)(insertions, deletions and substitutions)

recognize chromosomal mutations recognize chromosomal mutations (deletion, duplication, inversion, insertion, (deletion, duplication, inversion, insertion, translocation)translocation)

I. MutationsI. Mutations

……are any change in the DNA of an are any change in the DNA of an organism.organism.

May not have any affect or may cause a May not have any affect or may cause a major deformation, illness.major deformation, illness.

I. MutationsI. Mutations

……are any change in the DNA of an are any change in the DNA of an organism.organism.

May not have any affect or may cause a May not have any affect or may cause a major deformation, illness.major deformation, illness.

I. MutationsI. Mutations

Any change in DNA is a mutation.Any change in DNA is a mutation.

caused by caused by mistakesmistakes during… during… DNA replication of mitosisDNA replication of mitosis Transcription Transcription meiosismeiosis

Also can be caused by environmental factors like…Also can be caused by environmental factors like… Radiation Radiation Carcinogens Carcinogens

Mutations in Reproductive (Sex) Mutations in Reproductive (Sex) Cells VS. Body cellsCells VS. Body cells

-Mutations in sex cells a.k.a. gametes -Mutations in sex cells a.k.a. gametes (sperm and egg cells) can be passed (sperm and egg cells) can be passed down to a person’s children, but might not down to a person’s children, but might not affect the parentaffect the parent

-Mutations in body cells cannot be passed -Mutations in body cells cannot be passed on to your children, however, they can on to your children, however, they can cause cancer or other problemscause cancer or other problems

II. Cancer as a result of mutations in II. Cancer as a result of mutations in body cells:body cells:

II. Cancer as a result of mutations in II. Cancer as a result of mutations in body cells:body cells:

Tongue cancer and lung cancer are often caused by changes in body cells as a result of smoking, so don’t smoke!!!

Carcinogens- environmental/chemical factors that cause cancer

III. Gene MutationsIII. Gene Mutations

Point MutationPoint Mutation only 1 codon is affected only 1 codon is affected example: “substitution mutation”example: “substitution mutation”

AUC GGA UCC AUC GGA UCC AUC AUC CCGA UCCGA UCC

THE FAT CAT WAS MADTHE FAT CAT WAS MAD

THE FTHE FUUT CAT WAS MADT CAT WAS MAD

III. Point mutationIII. Point mutation

Normal

Point mutation

mRNA

ProteinStop

Stop

mRNA

Protein

Replace G with A

Point mutations in our lives!Point mutations in our lives!

-Sickle cell anemia is a blood disease caused by a -Sickle cell anemia is a blood disease caused by a SUBSTITUTION point mutation.SUBSTITUTION point mutation.

-A single nucleotide is changed from “A” to “T” -A single nucleotide is changed from “A” to “T” which causes the amino acid to change from which causes the amino acid to change from glutamic acid to valine:glutamic acid to valine:

Amino acids: Thr – Pro – Amino acids: Thr – Pro – GluGlu – Glu – Glu

Normal: ACT CCT GNormal: ACT CCT GAAG GAGG GAG

Sickle cell: ACT CCT GSickle cell: ACT CCT GTTG GAGG GAG

Amino acids: Thr – Pro – Amino acids: Thr – Pro – ValVal – Glu – Glu

Point mutations in our lives!Point mutations in our lives!

-People with sickle cell -People with sickle cell anemia often anemia often experience a lot of experience a lot of pain and swelling pain and swelling and have trouble and have trouble exercising.exercising.

IV. More Gene MutationsIV. More Gene Mutations

Frameshift MutationsFrameshift Mutations – – will affect several if not all of the following will affect several if not all of the following

codons! (MAJOR PROBLEM!)codons! (MAJOR PROBLEM!) Example: “Deletion” – one base was left out.Example: “Deletion” – one base was left out.

AAU CGA GGA … AAU CGA GGA … AAC GAG GA… AAC GAG GA…

(What is missing?)(What is missing?)

AAAAUU CGA GGA … CGA GGA … AAC GAG GA… AAC GAG GA…

IV. Frameshift mutationIV. Frameshift mutation

-A frameshift mutation is when one nucleotide -A frameshift mutation is when one nucleotide is inserted or deleted from the DNA or is inserted or deleted from the DNA or mRNA strand.mRNA strand.

-A frameshift mutation is worse…. WHY???-A frameshift mutation is worse…. WHY???

Ex: Ex: DNA DNA TACTTCAAACCGCGTAACATTTACTTCAAACCGCGTAACATT

mRNAmRNA

Protein

Difference between a substitution Difference between a substitution mutation and a frameshift mutation.mutation and a frameshift mutation.

substitution

THE FAT CAT WAS MAD…THE FAT CAT WAS MAD…

THE FAC ATW ASM AD…THE FAC ATW ASM AD…

Deletions cause a shift in the codons…just Deletions cause a shift in the codons…just like leaving a letter out, it makes no sense!like leaving a letter out, it makes no sense!

Other Frameshift Mutations:Other Frameshift Mutations:

“ “InsertionInsertion” – an extra base is added.” – an extra base is added.

ACC GAU GUC… ACC GAU GUC… ACU CGA UGU C… ACU CGA UGU C…

(What was added?)(What was added?)

ACC GAU GUC… ACC GAU GUC… AC ACUU CGA UGU C… CGA UGU C…

THE FAT CAT WAS MADTHE FAT CAT WAS MAD

THE FAD TCA TWA SMA D…THE FAD TCA TWA SMA D…

Once again, this makes no sense!Once again, this makes no sense!

Questions:Questions:

Is this a substitution mutation or a frameshift Is this a substitution mutation or a frameshift mutation?mutation?

-It’s a substitution mutation because G was replaced -It’s a substitution mutation because G was replaced with a T!with a T!

Questions:Questions:

THE DOG BIT THE CATTHE DOG BIT THE CAT

THE DOG BIT THE CARTHE DOG BIT THE CAR

Substitution or frameshift?Substitution or frameshift?

Substitution!Substitution!

QuestionsQuestions

THE DOG BIT THE CATTHE DOG BIT THE CAT

THE DOB ITT HEC ATTHE DOB ITT HEC AT

Substitution or frameshift?Substitution or frameshift?

Frameshift! The mutated sentence makes Frameshift! The mutated sentence makes no sense (non-sense) and thus the protein no sense (non-sense) and thus the protein will not be madewill not be made

Chromosome MutationsChromosome Mutations

……are usually damaging.are usually damaging.

An entire piece of a chromosome may be An entire piece of a chromosome may be deleted, moved or damaged.deleted, moved or damaged.

ALL INFORMATION ON THE AFFECTED ALL INFORMATION ON THE AFFECTED SECTION MAY BE LOST OR FOREVER SECTION MAY BE LOST OR FOREVER CHANGED (and is useless).CHANGED (and is useless).

Types of Chromosome MutationsTypes of Chromosome Mutations

DeletionDeletion – the whole chromosome is gone! – the whole chromosome is gone!

DuplicationDuplication – now you have 2 sets of the same – now you have 2 sets of the same stuff.stuff.

InversionInversion – one part of a chromosome gets – one part of a chromosome gets moved to another area on the SAME moved to another area on the SAME chromosome.chromosome.

TranslocationTranslocation – a section of a chromosome is – a section of a chromosome is stuck on a DIFFERENT chromosomestuck on a DIFFERENT chromosome

Chromosome MutationsChromosome Mutations

Summarizing Can you…Summarizing Can you…

define mutationsdefine mutations explain how mutations occur explain how mutations occur

when – DNA Replication or Meiosis when – DNA Replication or Meiosis how – radiation &mutagenic chemicals how – radiation &mutagenic chemicals

recognize point (N-base) mutations recognize point (N-base) mutations (insertions, deletions and substitutions)(insertions, deletions and substitutions)

recognize chromosomal mutations recognize chromosomal mutations (deletion, duplication, inversion, insertion, (deletion, duplication, inversion, insertion, translocation)translocation)