DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change...

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DNA MUTATIONS Type s Mutagen s Diseas es Click on an area for more informatio n Mutations are any change in the genetic make up of an organism and can occur naturally or can be increased by mutagens.

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Transcript of DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change...

Page 1: DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change in the genetic make up of an organism and can occur.

DNA MUTATIONS

TypesMutagens

Diseases

Click on an area for more information

Mutations are any change in the genetic make up of an organism and can occur naturally or can be increased by mutagens.

Page 2: DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change in the genetic make up of an organism and can occur.

TYPES OF MUTATIONS

POINT

CHROMOSOMAL ABBERATIONS

BLOCK

Click on an area for more information

Mutations can be spontaneous or natural as a result of errors in DNA replication or gamete production.

Error rate is 1 in 1,000,000 replications.

Page 3: DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change in the genetic make up of an organism and can occur.

Point mutations•Involves a change to one of the DNA bases that makes up a

gene.

•Also known as a MISSENSE mutation.

•Consequence varies depending on type of change.

Change DNA Change amino acid sequence

Change protein

Change organism

Click to find out more

Three types of point mutation

deletioninsertionsubstitution

Page 4: DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change in the genetic make up of an organism and can occur.

T A C T T C A A A C C G C G TDNA

Base Substitution

•Involves one base in the DNA being substituted by another.

•This mutation only affects one codon in the gene.

T A C T T C A A A T C G C G T

C is replaced by T in the DNA.

•End result is a different amino acid in protein.

•Generally minor effect on protein/organism.

•Known as NONSENSE mutation•Totally different protein made•Effect on organism can be dramatic

But…ATA

UAU

Tyr

mRNA

DNA ATT

UAA

STOP

•Serine is still added•Known as a SILENT mutation

AlsoAGA

UCU

Ser

mRNA

DNA AGG

UCC

Ser

Page 5: DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change in the genetic make up of an organism and can occur.

Base Insertion/Deletion

•Involves one base either being inserted or removed from the DNA sequence.

•Both these mutations affect all codons after the insertion or deletion.

•The earlier the mutation occurs in the sequence the greater the effect.

T A C T T C A A A C C G C G TDNA

T A C T T C A A A A C C G C G

Trp Arg

BASE INSERTION INSERTION

T A C T T C A A C C G C G T A

Known as frame shift mutations.

Dramatic effect on

protein made.

Page 6: DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change in the genetic make up of an organism and can occur.

Block mutations•Involves large scale changes in DNA segments on chromosome.

•Only occur during meiosis, formation of gametes (sex cells).

•Can affect the functioning of many genes

•Severe effect on functioning and characteristics of organism.

Change DNA Change amino acid sequence

Change protein

Change organism

Four types of block mutation

inversions

translocations

deletions

Click to find out more

duplications

Page 7: DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change in the genetic make up of an organism and can occur.

Deletion

•Section of chromosome is lost, anywhere from three bases to large segments.

•The DNA breaks due to the effect of mutagens.

break

A DB EC F HGA DB EC F HG

A DB EC F HG

segment is lost

STEP 2

A D E F HG

DNA ligase rejoins chromosome

STEP 3

A DB EC F HG STEP 1

genes

Page 8: DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change in the genetic make up of an organism and can occur.

Translocation

•Section of chromosome breaks and is joined to another chromosome.

•Problem when gametes formed-some receive extra genes, some deficient.

break

STEP 1

A DB EC F HG

3 42 51

segment removed

STEP 23 42 51

D E F HG

A DB EC F HGA DB EC F HG

D E F HG

DNA ligase joins segment

STEP 33 42 51A DB EC F HGA DB EC F HG

Page 9: DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change in the genetic make up of an organism and can occur.

Duplication•Segment of one chromosome is added to the homologous chromosome.

•Problem when gametes formed-some have double the genes, some have no genes.

STEP 1

A DB EC F HG

A DB EC F HG

break

D E F HG

STEP 3A DB EC F HGA DB EC F HGA DB EC F HG

D E F HG

A DB EC F HGA DB EC F HGA DB EC F HGSTEP 2

segment removed

Page 10: DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change in the genetic make up of an organism and can occur.

Inversion•Section of chromosome falls out and rotates through 180o.

•DNA ligase rejoins section but the genes are in reverse order.

•There is no loss of genetic information.

break

A DB EC F HG STEP 1

A DB EC F HGSTEP 2

segment rotates 180oA

D

B

E

C

F

HG

A

D

B

E

C

F

HG

segment rejoins

STEP 3A D B EC F HG

Page 11: DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change in the genetic make up of an organism and can occur.

Chromosomal abberations

•Loss or gain of entire chromosomes- called aneuploidy.

•Main cause is non-disjunction of chromosomes during meiosis.

•Gametes end up with extra chromosome(s) or fewer than 23 chromosomes.

2 x 23Normal diploid (2N) human cell containing 2 sets of chromosomes.

Through meiosis haploid (N) gametes are produced, containing only one set of chromosomes.

23

23

<23, >23

<23, >23

Mainly occurs with sex chromosomes.

Turner syndrome

Normal female

Metafemale

Normal male

Jacob syndrome

XO

XX

XXX

XY

XYY

Examples

Page 12: DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change in the genetic make up of an organism and can occur.

Mutagens

•Chemicals or radiation that increase the likelihood of a mutation occurring.

•Rate of mutation induced by mutagen is proportional to the dose of mutagen.

•Mutagens cause a decrease in the stability of the DNA molecule.

•Thus DNA more susceptible to error during replication or meiosis.

Types

Alcohol & dietary factors

•High fat, alcohol•Trigger cancers

Environmental poisons/irritants

•Benzene, asbestos•Tobacco tar, formaldehyde

Ionising radiation•Nuclear•UV rays•X rays

Viruses & micro-organisms

•Incorporate into genome•Trigger cancers

Page 13: DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change in the genetic make up of an organism and can occur.

Diseases

Sickle cell disease

Cystic fibrosis

Click on a disease to find out more about how it is caused by a mutation.

Down syndrome

Page 14: DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change in the genetic make up of an organism and can occur.

Sickle cell disease

haemoglobin

•Haemoglobin is made up of 4 polypeptide chains (2 alpha & 2 beta chains).

•Gene for beta chain is found on chromosome 11 and consists of 438 bases.

•A mutation occurs in the gene coding for the beta chain.

•The mutation is a substitution where adenine replace thymine on the DNA template strand.

•As a result the amino acid valine replaces glutamic acid.

•This change the properties of the haemoglobin and results in distorted red blood cells.

normal red blood cell

sickle cell

This single point mutation has a dramatic effect. Individuals have many health problems, eg weakness, jaundice, anaemia, heart & kidney defects, brain damage, skin lesions and inflamed spleen.

HBB gene on chromosome 11

Page 15: DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change in the genetic make up of an organism and can occur.

•Inherited disorder and occurs when an individual has both copies of the faulty gene.

•The gene (CFTR) is found on chromosome 7 and normally contains 1480 amino acids.

•A mutation occurs whereby the 508th triplet (AAA) is deleted resulting in a mutated CFTR protein of 1479 amino acids.

•The abnormal protein is unable to control chloride ion balance in cells.

•The build up of chloride ions in cells results in severe effects.

• Individuals have reduced life expectancy, high salt levels, blocked airways, pancreatic deficiencies and males are infertile.

•Cystic fibrosis is relatively common and occurs 1 in every 2500 individuals.

Cystic Fibrosis

CFTR gene on chromosome 7

AUU AUC UUU GGU GGUmRNA

ile ile phe gly valamino acids

TAA TAG AAA CCA CAADNA

506th 507th 508th 509th 510th

AUU AUC GGU GGU

ile ile gly val

mRNA

amino acids

TAA TAG AAA CCA CAADNA

506th 507th 508th 509th 510th

AAA

triplet deleted

Page 16: DNA MUTATIONS TypesMutagensDiseases Click on an area for more information Mutations are any change in the genetic make up of an organism and can occur.

Down Syndrome•Individuals have characteristic facial features, are relatively short,

slowed intellectual and physical development.

•Two main types of Down syndrome-97% non-familial, 3% familial.

Non-familial Familial24 23

One of the parent’s sex cells contains two no. 21 chromosomes, due to non-disjunction during meiosis.

One of the parents has only 45 chromosomes. A translocation has occurred where one of no.15 and one of no. 21 have joined together. One of the sex cells contain 23 but one of the 23 is the 15/21 chromosome.

•Arise from having 3 copies of chromosome 21

•known as trisomy-21.

15 21 15/21

Parent 1

Parent 2

Down child 3 no.21


Chromosomes/DNA Mutations. Chromosome Mutation Mutations are permanent gene or chromosome changes that will be passed on to offspring if they occur in.

Chromosomes/DNA Mutations. Chromosome Mutation Mutations are permanent gene or chromosome changes that will be passed on to offspring if they occur in.

MUTATIONS. Weird Genetics Mutations A change in genetic information Can occur randomly (naturally) Or can be deliberately.

MUTATIONS. Weird Genetics Mutations A change in genetic information Can occur randomly (naturally) Or can be deliberately.

1 MUTATIONS What Are Mutations? Changes in the nucleotide sequence of DNA May occur in somatic cells (aren’t passed to offspring) May occur in gametes.

1 MUTATIONS What Are Mutations? Changes in the nucleotide sequence of DNA May occur in somatic cells (aren’t passed to offspring) May occur in gametes.

List different movements/motion that occur inside an organism

List different movements/motion that occur inside an organism

Understand what mutations are Understand how they occur Analyze the different types of mutations Understand how mutations affect amino acid.

Understand what mutations are Understand how they occur Analyze the different types of mutations Understand how mutations affect amino acid.

Biallelic DICER1 mutations occur in Wilms tumoursresearch-repository.uwa.edu.au/files/3427895/NHMRC_PID_35072... · Biallelic DICER1 mutations occur in Wilms tumours. ... Biallelic

Biallelic DICER1 mutations occur in Wilms tumoursresearch-repository.uwa.edu.au/files/3427895/NHMRC_PID_35072... · Biallelic DICER1 mutations occur in Wilms tumours. ... Biallelic

Splicing factor mutations in myeloid malignancies · • Splicing factor mutations occur in ~ 50% of myelodysplasia (Dolatshad et al., Leukemia, 2015). • Spliceosome is a target

Splicing factor mutations in myeloid malignancies · • Splicing factor mutations occur in ~ 50% of myelodysplasia (Dolatshad et al., Leukemia, 2015). • Spliceosome is a target

BIG QUESTIONS: 1.ARE ALL MUTATIONS BAD? EXPLAIN.. 2.CAN EVOLUTION OCCUR IN ABSENCE OF MUTATIONS?

BIG QUESTIONS: 1.ARE ALL MUTATIONS BAD? EXPLAIN.. 2.CAN EVOLUTION OCCUR IN ABSENCE OF MUTATIONS?

Oncogenes and tumour suppressor genes 1. Cancer mutations occur in two forms.

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AIM: How do mutations occur in DNA ?

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Mutations & Genetic Engineering. Mutation A change in the nucleotide sequence of the genome of an organism.

Mutations & Genetic Engineering. Mutation A change in the nucleotide sequence of the genome of an organism.

MUTATIONS A mutation is a sudden change in the structure or the amount of genetic material. Most mutations are harmful to an organism, some have no effect,

MUTATIONS A mutation is a sudden change in the structure or the amount of genetic material. Most mutations are harmful to an organism, some have no effect,

DNA MUTATIONS · DNA MUTATIONS MUTATION = _____ to the genetic material of a living organism Anything that causes a mutation is called a _____ ex) Some types of mutations that could

DNA MUTATIONS · DNA MUTATIONS MUTATION = _____ to the genetic material of a living organism Anything that causes a mutation is called a _____ ex) Some types of mutations that could

Mutations. A Few Words on Mutations Mutations can be neutral, positive, damaging or lethal Can occur at the single base or chromosomal level Naturally.

Mutations. A Few Words on Mutations Mutations can be neutral, positive, damaging or lethal Can occur at the single base or chromosomal level Naturally.

Problem How do mutations occur? · 2017-03-13 · 1. Mutations 2. Point mutations 3. Gene substitutions 4. Gene insertions 5. Gene deletions 6. Chromosomal deletion 7. Chromosomal

Problem How do mutations occur? · 2017-03-13 · 1. Mutations 2. Point mutations 3. Gene substitutions 4. Gene insertions 5. Gene deletions 6. Chromosomal deletion 7. Chromosomal

From the previous lesson on mutation you should be able to: state what mutations are explain how mutations occur Adaptation, natural selection and the.

From the previous lesson on mutation you should be able to: state what mutations are explain how mutations occur Adaptation, natural selection and the.

Genetics of Cancer Part 2. Review Two mutations must occur:

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DNA Mutations. Mutations A mutation is a permanent change in DNA. Since DNA determines all aspects of an organism, even small changes can have big effects.

DNA Mutations. Mutations A mutation is a permanent change in DNA. Since DNA determines all aspects of an organism, even small changes can have big effects.

Mutations. What Are Mutations? Changes in the nucleotide sequence of DNA May occur in somatic cells (arent passed to offspring) May occur in gametes (eggs.

Mutations. What Are Mutations? Changes in the nucleotide sequence of DNA May occur in somatic cells (arent passed to offspring) May occur in gametes (eggs.

Changing the Genetic Information Mutations A mutation refers to any permanent change in the DNA nucleotide base sequence of an organism. Mutations occur.

Changing the Genetic Information Mutations A mutation refers to any permanent change in the DNA nucleotide base sequence of an organism. Mutations occur.