DNA Mutations and Genetic Diseases

Ch 13, 14, 15

What is a Mutation?

• Changes in the normal sequence of DNA

• Many different types and sizes

• One letter mistakes to whole chromosome mistakes

-Mutations that produce ______________ are usually harmful.-Harmful mutations are associated with many________________ and can cause

MUTATIONS can be:

HARMFULdefective proteins

genetic disorders cancer

Mutations can help an organism _________________

Provide a way for species to changeover time (evolution)

____________- Mutations are also a source of ______________ in thepopulation

MUTATIONS can be:

BENEFICIALgenetic variation

survive and reproduce

Mutations can happen:• when cells make_________ in copying DNA• when cells are exposed to environmental ___________ like __________- X-rays, tanning booths

__________ - cigarette smoke, pollutants__________ - HPV

_______________ are changes in the genetic material.

MUTATIONS

mistakes

REMEMBER!

carcinogensradiation

chemicalsviruses

Gene Mutations

• A mutation is a change or alteration, either in form or qualities

• Mutations involving 1 or more genes• Point Mutations = substitute one letter in for

another (A,G,T,C), usually not a problem• Frameshift Mutations = insert or delete

letters, throws off how the entire sequence is read = problem

Chromosome Mutations

• Changes in the number and structure of chromosomes

• Chromosome Duplication: extra piece of chromosome or an entire extra chromosome

• Chromosome Deletion: a piece of chromosome is lost or an entire chromosome is missing

Karyotype-picture of a persons chromosomes

Results of DNA Mutation Notes

Failure to Make the Right Proteins

Down Syndrome

• Trisomy 21 = 3 number 21 chromosomes

• Symptoms = distinct facial features, low communication skills, hearing and seeing problems, lower IQ

• Occurs mostly when women have children after 40

Phenylketonuria (PKU)

CAUSE: Mutation in gene for an ___________ that __________ an ___________ called phenylalanine

Build up causes ________________________MENTAL RETARDATION

ENZYME

http://biology.clc.uc.edu/courses/bio104/protein.htm

breaks down amino acid

X

X

Phenylketonuria (PKU)

____ babies are ________for PKU before they leave the hospital.

Treatment: Need a diet _____________________ to extend life and ______________ mental retardation

If phenylalanine is an _____________, what type of foods should PKU patients avoid?

__________________

amino acid

PROTEINS !

LOW in phenylalanine

PREVENT

ALL tested

http://labspace.open.ac.uk/file.php/2588/SK195_6_002i.jpg

THINK ABOUT IT

What does a can of Diet Coke have to dowith human genetics?LOOK AT THE WARNING LABEL !

______________ is made with phenylalanineNUTRASWEET

Hemophilia

• Blood doesn’t clot correctly

• Risk of bleeding to death • A X chromosome deletion• 1 in 400 babies affected

yearly• Treatments add clotting

factors to blood so that it will clot correctly

Albinism• Lack of melanin pigment• Cause: gene mutation on

#11, #15, or #9• Symptoms: little or not

pigment in the skin, hair, and eyes; bad vision, sensitive skin

• 1 in 17,000 people• Special glasses and

protective clothing must be worn when outside

Proteus Syndrome• Deletion on

chromosome #11• Symptoms:

atypical bone growth, tumors on and beneath skin

• Very rare• The elephant man?

Achondroplasia

• Gene affected on chromosome #4

• Symptoms = short arms and legs, normal sized head and spine, normal IQ

• Possible for 2 dwarfs to have a normal sized child

• 1 in 15,000 people have it

Sickle Cell Anemia

• Gene on chromosome #11 is affected

• 1 in 635 babies, more common in African Americans

• Sickle shaped blood cells result in painful arms and legs, breathing problems, dehydration, swelling

Huntington’s Disease• Duplication on chromosome

#8• Uncontrollable muscle

spasms, deterioration of the brain, death

• Symptoms don’t show up until 30 –50 years old, so you pass it on to your kids without even knowing (50% chance)

Turner Syndrome

• Female who is missing an X chromosome

• Symptoms: short, webbed neck, infertile, bone deformations

• Hormone replacement therapy helps relieve symptoms

Klinefelter’s Syndrome• Men that are XXY• 1 in 700 men have it• Symptoms: Normal

males (some develop feminine traits) they are just infertile

• Most men don’t know that they have it until they try to have children

Cleft Lip and Palate

• A large gap in the roof of the mouth and lip

• Didn’t form correctly before birth

• Side effect of other genetic diseases and of fetal alcohol syndrome (drinking while pregnant)

• Surgery can return to normal, but expensive

Cri du Chat Syndrome

• Missing piece of chromosome #5

• Symptoms: slow growth rate, high pitched scream (cat like), low IQ, webbed fingers and toes

• Very rare

Progeria or(Hutchinson Gilford)

• Caused by a “fresh” mutation or has occurred only by chance in the child and does not occur in either of the parents.

• Only 10-12 people worldwide have it at one time

• Age 10 times faster• Die of heart failure at 10-15

Manipulating DNA

Chapter 14-3

Manipulating DNA

• Scientists can cut and paste DNA to get specific sequences that they want

• Very similar to cutting and splicing video tapes

Tools of DNA Manipulation

• Cutting DNA = Restriction Enzymes– Specific enzymes

cut DNA at specific sequences

– (ex) ecoR 1 cuts the DNA at every CTTAAG sequence

Tools of DNA Manipulation

• Separating DNA = gel electrophoresis – The cut up DNA is put

on the jelly and a electrical current is passed through it

– The DNA gets separated by size

– The largest pieces don’t travel as far as the smaller pieces

Tools of DNA Manipulation

• Making Copies of the DNA = PCR– A Polymerase Chain

Reaction machine makes copies of the sequences that you want

• Reading the DNA = dyes and special microscopes- dyes make it possible to

tell the difference between A, T, G, and C

What can we do with

these tools?1. Forensics: see if DNA from

the crime scene matches a criminal’s DNA

2. Putting specific genes into plant and animal cells

3. Putting human genes into bacteria to make multiple copies for synthetic use

4. Genetically modified foods

Human Genome Project

Our Findings

Goals of HGP

• Sequence Entire Human Genome

• Identify Genes• Chart Variation• Sequence other organisms

Successes• Completed Early (1990-

2003)• Discovered

– Only 20,000 Human Genes

– vs. 100,000 Human genes(previous guess)

• Mapped Genomes– Chimpanzee– Mouse– Rat– Fruit Fly

Other Successes• Unraveled Cancer genetics

– Individualize treatment

• Changed Ideas of DNA– Epigenetics

• SNP’s (Single Nucleotide Polymorphisms)– Different by 10 million letters– Only .1 % of total genes

What’s Next?• Understand functions of genes• Catalogue Human Variation• How it all works together?

In the course of human progress, it has been far easier to understand the things we make, rather than what makes us

Genetic EngineeringChapter 14-3

Genetic Engineering

• Humans changing the sequence of DNA

• Get traits that we want

• Selective breeding, cloning, DNA manipulation and transformation

Selective Breeding

• Humans controlling who gets to breed so that we can control the traits in the next generation

• All domestic animals: dog breeds, milk and beef producing cows, etc…

Hybridization• Cross two dissimilar

organisms to get offspring with the best traits from both

• Only breed the cows that produce the most milk

• Cross a corn plant that produces a lot of corn to one that resistant to insects

• Horse X Donkey = Sterile Mule

• Zorse (zebra and horse)• Cama ( Camel and Llama)

Inbreeding• Continued breeding of individuals with the

desired characteristics• Maintains the traits that you want• Over inbreeding = joint deformities and

blindness

Modern BiotechnologyModern Biotechnologysome examplessome examples

• Recombinant DNA• Stem cell therapy• Cloning• Designer drugs• Genomics• Gene Therapy

What are the potential benefits?What are the potential dangers?What are the ethical issues?

Recombinant DNA• Taking the DNA of one organism and

attaching it to the DNA of another.• Uses Plasmids

– Circular pieces of bacterial DNA– Must contain a replication start signal

(ori)– Must contain a restriction enzyme

cutting site

• http://webapps.css.udel.edu/biotech/rDNA.html

Genetically Modified Genetically Modified BacteriaBacteria

Cloning• Creating Genetically identical

individuals• 1997 the sheep Dolly was

cloned and she produced a viable offspring so it was a success

• An egg is removed and a cell from the adult that you want to clone is fused with it. The egg cell is than placed into a foster mother where it develops normally

Cloning in Agriculture

Other Cloned Animals

• Five cloned pitbull puppies are seen with their 'mom' at the Seoul National University Hospital for Animals in South Korea.

Prometea and Pegaso(Cloned horse and offspring from cloned horse.)

Transgenic Organisms• organisms that have

genes from other organisms inserted into their DNA

• Bacteria = human insulin producers

• Animals = lab rats with human immune systems, bovine growth hormone

• Plants = plants that have genes that make them resistant to insects, herbicides, and drought

GMO’s• Genetically Modified

Organisms• Almost all of the fruits

in vegetables sold in the USA have been genetically modified

• (92% soy beans, 80% corn etc..)

• Should they be labeled????

GMO Benefits• Decreased Pesticide

Usage– Bt toxin gene

• Decreased Spoilage• Prevent Disease

– Golden rice (vitamin A)

• Source of Human Medicine – Human proteins from

milk– Insulin– Blood clotting factors

GMO Cons• Cause extinction of

beneficial insects– Bt toxin

• No safety testing of GMO food– Allergies– Long term

• Non-scientific purposes– Cloning Humans/Pets– Designer babies– Glo-Fish