Mutations and DNA Technology

What is a mutation?

• A mutation is a change in DNA• Two types of mutations are gene mutations and

chromosome mutations.

Gene mutations

• A POINT MUTATION is a mutation that affects one nucleotide or one base.• Sometimes your cell catches it when

proofreading.• What will happen?• The wrong amino acid may be put into place.• Example: sickle cell anemia• YOU ARE FAT >>>> YOU ARE CAT• ATA TAG CCA >>>>> AAA TAG CCA

• A FRAMESHIFT mutation involves the insertion or deletion of a nucleotide or base.• This causes a shift in the whole sequence.• This usually causes something bad to happen.• THE CAT ATE THE RAT. >>• THC ATA TET HER AT• ATT CCA TAG >>>> ATC CAT AG• Every amino acid put in will be wrong.

Chromosomal mutations

• Occurs during meiosis.• The resulting gamete will have the wrong

number of chromosomes.• These tend to increase as parents get older.

Down Syndrome

Turner syndrome

• There is only one X chromosome on the 23rd pair.• This is a female. (1/2500)• She is underdeveloped.• She is short . 4’7”• May have webbed neck, low hairline on back of

head, drooping eyelids, lower set ears, edema of hands and feet.• Usually sterile.

• What about a person with only one Y chromosome? (lacks an X)• He will not live. Why?

Klinefelters

• Male• 1/500-1/1000 males• Tall• Reduced fertility• Less muscle control and coordination• Less facial hair and broader hips• Language and reading difficulty

XYY syndrome

• Tall male• May not have any phenotypic differences• Was associated with criminal or antisocial

behavior.

Trisomy

• Can be any chromosome.• Usually cause extreme effects in people and

animals.• Plants survive.

Are all mutations bad?

• Some are bad.• Some are harmless• Some may actually be beneficial.

• Mutations in body cells affect the organism.• Mutations in gametes affect the offspring.

Mutagens

• A mutagen is something that causes a mutation.• Industrial chemicals• UV light• Any radiation• Drugs• Chemicals

Genetic engineering

DNA fingerprinting

• Every person has their own unique DNA fingerprint.• Can be used for identification.• Can be used to establish paternity.• Study human migration.

Cloning

• Genetically identical copy of an organism.• Can be done easily with plants. (Also occurs

naturally.)• Can be done with animals.• Should it be done with people.

• the boys from brazil - rabbit cloning – YouTube• GCSE Science Revision - Cloning Dolly The Sheep - YouTube

Genetic engineering

• Taking DNA from one organism and inserting it into the DNA of another organisms. This is called recombinant DNA.• The new organism is a transgenic organism.• We do this to make insulin.• We take an insulin gene from a person and put it

into the DNA of a bacteria. What do we get? Bacteria that produce insulin.

• We have created plants that are resistant to frost, diseases and insects.• We can increase crop yields.• We have developed animals for research.

Human genome project

• Sequence the human genome.• Find all of the genes on all of the chromosomes.

Gene therapy

• Repair defective genes.• Still very experimental.• Should we do it?