Unit 6 Cell and Molecular Genetics

GATTACA

Honors Biology Unit 6• “Back to Mitosis”

• Gregor Mendel never observed chromosomes, genes, mitosis or meiosis. His work identified “factors” of heredity but these “factors” remained a mystery until improvements in microscopy allowed scientists to observe the details of cell division.

• The scientist who first observed chromosomes during mitosis in 1882 was Walther Flemming.

The chromosome theory states that hereditary factors, or genes, are carried on chromosomes (Walter S. Sutton, 1903).

Walther Flemming

• How did this theory come to be? • Chromosomes in grasshoppers line up in homologous pairs during meiosis

just like Mendel’s “factors”. Chromosomes behave according to Mendel’s principles.

• Supporting Evidence

• 1. 1st the egg and sperm were known to be the only physical link between generations.

• 2. 2nd Males and females appeared to contribute traits to offspring equally.

• 3. 3rd Nuclei in egg and sperm about the same size even though the egg is larger and has much more cytoplasm

• So… heredity factors must be in the “nucleus”

• Genes and chromosomes: Organisms have more traits than chromosomes – each chromosome therefore must carry hundreds of genes.

• Example: Sutton was observing Grasshoppers, 12 pairs of chromosomes producing hundreds of traits.

• The Sex Chromosomes (X,Y)

Classic experiments with Drosophila or fruit flies (10-15 day life span) by Thomas Hunt Morgan

Demonstrating that a specific gene (such as eye color) is located on a chromosome.

• Why is Drosophila a good choice for the study of heredity?

• 1. easy to keep and breed

• 2. small, 100’s in a small vial

• 3. life span 10-15 days

• 4. many generations in short time

• 5. only 4 pairs of chromosomes

• X Chromosome (rod shaped) and Y chromosome (hooked shaped)

• Each egg has X

• Each sperm has X or Y

• The chromosomes that determine the sex of an individual are called the sex chromosomes. The other chromosomes are called the autosomes .

• Fertilization and sex chromosomes – (draw)

• Sex Linkage in Fruit Flies

• The White eye experiment

• Two types of eyes – red or white.

• Thomas Morgan crossed a red eyes female with a white eyes male. All of the white eyes disappeared. Then he crossed the babies (both male and female with red eyes).

• He got ¾ red and ¼ white. BUT all of the white eyed babies were male. How do you explain this? Explain Using Punnet Squares

Fruit Flies Mating

• Morgan’s experiments confirmed Suttons’s hypothesis that genes are found on chromosomes. Since males have only one chromosome – any allele present will be expressed. How can the recessive alleles be expressed in females?

• The recessive allele must be on both X chromosomes which is much more rare.

• Human Traits which are sex linked include:

• 1. Red Green Color Blindness

• 2. Hemophilia

• 3. Duchenne Muscular dystrophy

• Which sex is more likely to exhibit a sex linked trait?

• Male

Bryan Arnold Duchenne

Male Pattern Baldness

• Karyotypes

• A picture of the chromosomes in a cell from an organism is called a

• Karyotype

• 1. Tissues used for chromosomes analysis

• a. Blood Cells/Lymph Cells• b. Amniotic Fluid (surrounds fetus)• c. Skin• d. Bone Marrow

• KARYOTYPING RULES• A. Chromosomes are arranged according to size from

largest to smallest with the short arm (p arm) up and the long arm (q arm) down.

• B. Each chromosome is paired up with its matching homolog so there are two chromosomes in each space. Each homolog has the same banding pattern and centromere index. Unless there is an abnormality, the banding and centromere index are always the same for each numbered pair.

• a. Metacentric centromeres (# 1 and 3)• b. Telocentric centromeres (#13 and 21)• c. Sub-metacentric centromeres (#2 and 6)

• Sex chromosomes are put into the X or Y spaces

• The Karyotype is Named with number first and then the sex chromosomes, and then the abnormalities present.

Normal Female Karyotype

Normal Male Karyotype

THE CHEMISTRY OF GENETICS

• When analyzed by biochemists, chromosomes were found to be made up of two different chemicals which were:

• 1. DNA• 2. Proteins

• For years scientists thought that protein was the genetic material but in 1950 it was discovered that DNA was that material:

• The Puzzle and the Proof

• Two strains of Streptococcus – Strain S had a protective capsule and will kill mice by giving them pneumonia. Strain R is harmless and has no capsule.

• Experiment• 1. Kill the deadly strain S with heat• 2. Inject into mice – no pneumonia• 3. Inject mice with heat killed S and living R –

pneumonia and death

• Why?

• Did Strain S come back from the dead? How did they solve this?

• They realized that the virulent strain could transfer the DNA to the non-virulent strain and make it deadly

• Another Proof: Virus formation in infected cells.

•

• MOST IMPORTANT OF ALL SCIENTIFIC DISCOVERIES

• Discovering the structure of DNA by ______________ and _____________

• Chemical make-up of DNA. It consists of four nitrogenous bases:

• 1. Adenine• 2. Guanine• 3. Cytosine• 4. Thymine

• DNA also has two other molecules: • Ribose Sugar • Phosphate Backbone

James Watson

Francis Crick

• Structure of a Nucleotide: (DRAW)

• A unit made of a nitrogen-carrying base, a sugar molecule and a phosphate group is called a Nucleotide

• The Watson-Crick Model

• Known information about DNA:

• 1. The amount of guanine always equals the amount of cytosine

• 2. The amount of adenine always equals the amount of thymine

• Images of DNA were made by a biophysicist named• Rosalind Franklin

• The DNA image looked like what? • A Ladder• Two graduate students named ________________ and

_________________ worked in a laboratory with tinker toys and figured out the structure. They published first.

• Determined that DNA is shaped like a• Spiral Ladder or Spiral Staircase.

• The sides of the ladder (helix) consists of alternating Phosphates and Deoxyribose Sugars.

• The rungs of the ladder consist of• Nitrogenous Bases (Adenine, Guanine Cytosine, Thymine)

James WatsonFrancis Crick

• The sequence of the nucleotides is the code that controls the production of all the proteins in an organism.

• A gene is a sequence of nucleotides that controls the production of a polypeptide or an RNA molecule.

• Scientists estimate that the information stored in one cell is the amount in 500-1000 page books.

DNA from Thymus

SKETCH OF DNA

Replication of DNA

• Cells make copies of their DNA in about six hours through a process called:

• Replication• To make a copy:

• 1. DNA unwinds with help from enzymes• 2. Enzymes pair complimentary nucleotides on each side.• 3. Other enzymes link other nucleotides into 1 long strand.

• Each original strand serves as a template (blueprint) or pattern.

• Each completed DNA molecule contains one old and one new strand.

• The enzyme responsible for this is• DNA Polymerase

Replication diagrammed:

DNA AND PROTEIN SYNTHESIS

• DNA controls protein synthesis

• DNA is located in the• Cell Nucleus.

• Protein synthesis takes place in the • Cytoplasm of the cell

• DNA molecules do not leave but use a messenger called• RNA or Ribonucleic Acids.

• DNA and RNA are similar in many ways but have 3 key differences:

• 1. Contains the sugar Ribose instead of Deoxyribose• 2. Uracil is substituted for Thymine in RNA• 3. RNA is single stranded where DNA is double stranded

• There are three kinds of RNA

• 1. Messenger RNA (mRNA) (carries sequences from nucleus to ribosome)

• 2. Transfer RNA (tRNA) (picks up amino acids and carries them to ribosome.

• 3. Ribosomal RNA (rRNA) (binds mRNA and tRNA together)

RNA Structure

TRANSCRIPTION

• Process by which mRNA is copied from DNA is called

• Transcription

• What happens?

• 1. 1 strand of DNA separates from helix (template)

• 2.mRNA binds to the DNA making a sequence for proteins

The SECRET CODE

• We need a code made of DNA to make a protein.

• There are 20 amino acids.• If a code = 3 bases (AUG) – How many

amino acids? • 1 Amino Acid • Experiments have confirmed the triplet codon. Each set of 3 letters = one Amino Acid.

• Codons code for all amino acids (redundant).

• They also code for STOP, START, and other punctuation.

• AUG = Start and UGA, UAA, UAG=Stop.

• Lets try a simple mRNA code Transcription:• AUG-UAC-UUU-GUU-GGA-AAA-UCU-UGA

1st Base 2nd Base 3rd Base U C A G U

Phenylalanine Phenylalanine Leucine Leucine

Serine Serine Serine Serine

Tyrosine Tyrosine Stop Stop

Cysteine Cysteine Stop Tryptophan

U C A G

C

Leucine Leucine Leucine Leucine

Proline Proline Proline Proline

Histidine Histidine Glutamine Glutamine

Arginine Arginine Arginine Arginine

U C A G

A

Isoleucine Isoleucine Isoleucine Methionine

Threonine Threonine Threonine Threonine

Asparagine Asparagine Lysine Lysine

Serine Serine Arginine Arginine

U C A G

G

Valine Valine Valine Valine

Alanine Alanine Alanine Alanine

Aspartic Acid Aspartic Acid Aspartic Acid Aspartic Acid

Glycine Glycine Glycine Glycine

U C A G

TRANSLATION

• After transcription, the mRNA moves out through a• Nuclear Pore

• In the cytoplasm mRNA and, rRNA, tRNA complete a process called Translation.

• Several ribosomes are used (at the same time sometimes).

• Ribosomes: 2 part segment that is the workbench for building proteins

• Made up of 2 Separate parts (includes rRNA)

• Also needed is Transfer RNA (tRNA)- which picks up a specific amino acid and carries it to the mRNA and ribosome complex.

• Translation •

• The cytoplasm has more than 20 kinds of tRNA – • at least one for each amino acid

• tRNA (80 nucleotides long)

• The sequence of three bases which matches mRNA is called the Codon. UAA, UUU, AAU, AUG

• Once the tRNA has bound to mRNA an enzyme in the ribosome links the new amino acid by means of a Peptide Bond.

• There is no tRNA for the termination codon so the chain is released and the protein is completed. (It may go to the golgi body now for modifications).

Transformation Lab – pGlo• Focus Questions pg 39

• 1. To genetically transform an entire organism, you must insert the new gene into every cell in the organism. Which organism is better suited for total genetic transformation – one composed of many cells, or one composed of a single cell?

• Singled Cell Organisms.• Multi-celled organisms often have cells with different jobs, and the genes would

be expressed differently• 2. Safety is another important consideration in choosing an experimental

organism. What traits or characteristics should the organism have (or not have) to be sure it will not harm you or the environment?

• It should not be pathogenic (harmful to a human body, or a germ)• It should be able to multiply quickly to observe large quantities at a time.• The cells should be expressing the same DNA • 3. Based on the above considerations, which would be the best choice for a

genetic transformation: a bacterium, earthworm, fish or mouse? Why?• Bacterium: they divide quickly, can be contained in a small area, and the cells

each express the same genetic information

DATA Collection:• Carefully observe and draw what you see on each of the

four plates. Put your drawing in the data table below. Record your data to allow you to compare observations of the +pGLO cells with your observations for the non-transformed E. Coli. Write down the following observations for each plate.

• a. How much bacterial growth do you see on each plate, relatively speaking.

• b. What color are the bacteria• c. How many bacterial colonies are on each plate (count

the spots)

ANALYSIS pg 41• 1. From your results, can you tell if these bacteria are

ampicillin resistant by looking at them on the LB plate?• Yes, if Bacteria grow on the plates that contain Ampicillin,

then the bacteria have developed a resistance.• 2. How would you change the bacteria’s environment

to best tell if they are ampicillin resistant?• Once the bacteria have grown on the plate, ampicillin

would be place directly on the bacteria. If they continued to grow, then they would be resistant to bacteria

• 3. Very often an organism’s traits are caused by a combination of its genes and its environment. Think about the green color you saw in the genetically transformed bacteria.

• a. What two factors must be present in the bacteria’s environment for you to see the green color?

• There must be the enzyme necessary for gene transformation (beta-lactamase) pGLO and arabinose sugar in the agar.

• b. What do you think each of the two environmental factors you listed above are doing to cause the genetically transformed bacteria to turn green.

• The gene that provides resistance to ampicillin also contains the jellyfish gene• The gene is also turned on to break down arabinose for food for the bacteria

• c. What advantage would there be for an organism to be able to turn on or off particular genes in response to certain conditions?

• This allows the bacteria to be able to adapt to more conditions (allows it to survive in less than ideal situations)

• 4. How might transformation be used:

• a. In agriculture?• Growing better crops. Genetically Resistance to disasters• Bacteria Killing insects • Nitrogen fixing bacteria• b. In medicine• Make hormones like insulin that are in high demand• Penicillin• Cancer treatment

• c. In environmental disasters????• Use bacteria to re-cultivate the natural plants and soil in

the area

CHANGES IN THE GENETIC CODE• DNA usually copies itself exactly

• Occasionally, replication makes mistakes or environmental factors cause a change in the genetic code.

• This change is called a Mutation.

• The product of this change is the• Genetic Disease

• Diseases that are caused by these gene mutations happen often. Some diseases are:

• 1. Down’s Syndrome• 2. Muscular Dystrophy • 3. Turner’s Syndrome

• Mutations that cause the death of the offspring are called Lethals.

• Chromosome mutations

• Involve changes in many genes.

• Deletion, Inversions and Translocations

• Somatic and Germ Mutations

• Germ mutations occur in Sex Cells (transmitted to offspring)

• Somatic mutations occur in Body Cells (only individual is affected)

• Deletion:• Inversion:• Translocation:

Base Substitution• One or few bases are replaced by different ones

AGC CTA AGT CTA DNA

UCG GAU UCA GAU mRNA

Ser – Asp Ser – Asp Protein

AGC CTA AGC TTA DNA

UCG GAU UCG UAU mRNA

Ser – Asp Ser – Tyr Protein

• May or may not change amino acid at that position• Does NOT cause frameshift

No

Change

Change

Original DNA Strand

DNA sequence:

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

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

Protein:

RNA G G G G GGC CU UU UAAA AUUU U

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Met – Ser – Iso – Met – Cys – Stop

Base Substitution

DNA sequence:

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

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

Protein:

RNA G G G G GGC CC UU UAAA AUUU U

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Met – Pro – Iso – Met – Cys – Stop

Substitute base # 6 (“T”) with a “C”.

G

Insertion

DNA sequence:

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

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

Protein:

RNA G AC A U G GGCU UU UAA AUU U

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Met – Cys – Stop

Insert an “A” between bases 4 and 5 in the DNA sequence

G

Deletion

DNA sequence:

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

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

Protein:

RNA G G G G GGC CU UU UAAA AUUU U

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Met –

Delete base # 7 (“C”) in the original DNA sequence

Stop

Deletion

• One or a few bases are removed

TGC TCA G TG –T CAGACG AGU G AC A GUC Thr – Ser Thr – Val

• Causes frameshift – changes how codon sequence is read

• Amino acid sequence is changed

Other Types of Mutations

Inversion A section of DNA is flip-flopped and ended up backwards in the same location on the chromosome

Duplication The same section of DNA appears twice on the chromosome

Transposition A gene is moved to another location on the same chromosome

Translocation A gene is moved to a different chromosome

Chromosomal rearrangement

A part of a chromosome is moved to another chromosome

EFFECTS AND FREQUENCIES OF MUTATIONS

• Nearly all chromosome mutations in animals are harmful because they result in deformities and other traits that make it difficult for the organism to survive in its environment.

• Some mutations give the individual an advantage such as drug resistance or the ability to survive or compete in an environment (evolution).

• These are rare – most evolution is from a new combination of genes already present.

• Anything that causes a mutation is called a• Mutagen.

• Examples of Mutagens include: • Tar, tobacco, viruses, smog, chemicals, and

drugs.

Cause and Effect of CarcinogensCancer

– Disease identified by uncontrolled cell division and the ability of the cells to spread to other parts of the body

Carcinogens– Agents thought to cause cancer

– Examples are chemicals such as cigarette tar, pesticides, and ionizing radiation such as X rays or UV rays from the sun

GENETIC TECHNOLOGY

• CLONING• Cloning is the production of organism with• The same DNA• The most simple method = cutting branches

from certain plants and re-planting them• More complex method is by growing a

complete plant from one somatic cell.

In animals (DIAGRAM AND EXPLANATION).

• Polyploidy:

• When an organism has more than two paired sets of chromosomes for a particular autosome:

• Common in plants and some animals but can cause genetic disease in humans

GENETIC ENGINEERING• Genetic Engineering is accomplished by • Transferring DNA from one organism to DNA of

another organism• The new molecule of DNA is called • Recombinant DNA• An example and disease where this

works is • Diabetes • The hormone Insulin is cloned.

Producing Recombinant DNA(Honors)

• Often this is done in bacteria called e-coli. A special piece of bacterial DNA called a plasmid can be modified.

• Steps:

• a. Extract DNA from e-coli.

• 2. Enzymes called restriction endonucleases cut the DNA and remove a gene. Where did these enzymes come from? Bacteria and are used to kill viruses!!!!

Restriction Enzymes

5’ 3’ G A A T T C C T T A A G 3’ 5’

Leave Sticky Ends – Example Eco RI cuts at palindrome 5’ G A A T T C 3’ 3’ C T T A A G 5’

• 3.Plasmids are extracted from e-coli. This DNA is broken with the same restriction enzymes.

• 4. The plasmid DNA is bonded with the donor DNA (polymerase seals them)

• 5. Next the plasmids are inserted into the E. coli. Every time the bacteria divides so do the plasmids.

• 6 The bacteria can now be used to make whatever protein that the inserted DNA codes for.

GEL ELECTROPHORESIS

• Molecules in a mixture are separated or resolved based on their

• Proteins• The technique is called• Gel Electrophoresis

• It is dependent on the fact that dissolved molecules in an electric field move at a speed determined by their

• Size (Smaller segments move farther faster)• In solution, nucleic acids have a • Negative charge because their Phosphate groups are

ionized. • Therefore, they migrate toward a positive electrode.• Since nucleic acid molecules (made of nucleotides)

have almost identical Charge/Mass ratios regardless of length, they can be separated according to

• Their length

• Molecules are subjected to an electric charge across a gel and are only limited in the rate of movement by Pores in the gel

• which the molecules must tunnel through. Basically the Larger molecules move more slowly than the Smaller ones.

• Materials needed: Gel, Salt solution, Electric charge (Tupperware)

Molecules move through pores at a rate inversely proportional to their chain length.

Neg charged nucleic acids

Agaraose Gels

Negative

Positive

When is Gel Electrophoresis Used? Honors

• Mapping• • A DNA molecule is cut with Restriction enzymes and then

the distinct fragments are separated according to size. • The movement down the gel generated by an electric

current produces a series of bands with each band corresponding to a fragment of a particular length and with the ends having the same restriction sequence.

• By running a piece of DNA of known lengths (called a ladder), a gene/plasmid map can be constructed from the fragments.

When is Gel Electrophoresis Used?

• RFLP (Restriction Fragment Length Polymorphisms)

• The difference in DNA between individuals can be determined.

• Each allele is distinctive in where the restriction enzymes cut (different pattern of sequences). Therefore the DNA of one person can be seen as different from another.

• This technique is used for a process called • DNA Fingerprinting

• It is particularly useful in identifying DNA in crime scenes etc.

• Example: Dr. Sam Sheppard

Examples

• Sequencing DNA

• This technique is used to see the positions of

• DNA

• It uses the process of PCR (explained in a bit)and adds a poison nucleotide randomly throughout the process. When the poison nucleotide is added, then the replication stops.

Banding (Honors)

Whole DNA strand GCTTATCG Replication Process begins in 4 test tubes. Tube 1 Tube 2 Tube 3 Tube 4 (Poison A) (Poison T) (Poison C) (Poison G) GCTTA GCT GC G GCTT GCTTATC GCTTATCG GCTTAT

Banding continuedHonors

These pieces are now separated on a gel The Banding pattern will look like this: Poison A Poison T Poison C Poison G GCTTATCG ________ GCTTATC _______ GCTTAT ______ GCTTA _____ GCTT ____ GCT ___ GC __ G _

• Read the bands backward and you have the position of the DNA nucleotides.

• Blotting (Northern Blots and Southern Blots)• This is a way to save the DNA on the gels for

other uses.• Specific sequences of DNA can be isolated and

later identified etc.• DNA blotting = Southern • RNA blotting = Northern

• Drawing of Technique (requires a nitrocellulose filter)

PCR POLYMERASE CHAIN REACTION• Once you’ve isolated your DNA, what if you don’t have enough of

it?

• Using the process of PCR Polymerase Chain Reaction to make more.

• You will need a machine called a Thermal Cycler or you can do it in water baths but you better have a good 8-10 hours for standing around and moving test tubes.

• The sections of the gel with the DNA are removed and then the DNA is isolated and purified. This technique will produce a much larger quantity of the desired piece of

• DNA

Thermal Cycler

HYBRIDIZATION (Honors)• Since: Guanine only binds to Cytosine and Adenine only binds to Thymine,

we can play a little and identify specific pieces of DNA if we know what we’re looking for.

• A technique called hybridization can be used to identify a specific sequence of DNA on a gel, in the PCR technique and on metaphase (chromosome and karyotype) spreads.

• PCR – the “Primer” thing. A primer will always bind to a complimentary piece of nucleic acid and begin replication with the appropriate sequence present.

• Gel Electrophoresis – A specific sequence can be identified by using a known primer that has a radioactive probe on it.

• Chromosomes – Specific chromosome fragments can be identified using a • known sequence and then hybridize (stick) to the metaphase.

The Calico Cat• Cats have two sex chromosomes. Chromosomes carry

genes and genes have traits like coat color, eye color etc.

• Sex chromosomes define gender. Females produce on X chromosomes in their egg and males produce both x and Y chromosomes in their sperm.

• Unlike other coat color genes, the gene that determines red coloration can be carried only on the X chromosome. The gene that determine red or orange coloration in cats is called O (for orange). (O = orange and o = non-orange).

• If the cat inherits an O pattern proper for its gender, the cat will be red or orange.

• This orange will cover up all other colors. If the cat inherits an o pattern it won’t be orange. Males only have one X chromosome so they either have an O gene or not.

• Females get one X from each parent, so they get two O genes. In regular Mendelian Genetics the O and o genes would be4have like dominant and recessive genes.

• However in cats because these genes are located on the X chromosome some cells in each female will be expressing the O gene which just happens to be on the active X and in other cells the o gene will be on the active X.

• Complete the following Punnet Square and Probability Problems and determine the outcome of breeding the following cats

1. Calico female and non-orange male.

Muscular Dystrophy

Signs and symptoms

Signs and symptoms vary according to the type of muscular dystrophy. In general, they may include:

• Muscle weakness • Apparent lack of coordination • Progressive crippling,

resulting in contractures of the muscles around your joints and loss of mobility

Duchenne Muscular Dystrophy• The most severe form of dystrophinopathy. It

occurs mostly in young boys and is the most common form of MD that affects children. Signs and symptoms of Duchenne MD may include:

• Frequent falls • Large calf muscles • Difficulty getting up from a lying or sitting

position • Weakness in lower leg muscles, resulting in

difficulty running and jumping • Waddling gait • Mild mental retardation, in some cases • Signs and symptoms of Duchenne usually

appear between the ages of 2 and 5. It first affects the muscles of the pelvis, upper arms and upper legs. By late childhood, most children with this form of muscular dystrophy are unable to walk. Most die by their late teens or early 20s, often from pneumonia, respiratory muscle weakness or cardiac complications.

Causes• Duchenne and Becker's

muscular dystrophies are passed from mother to son through one of the mother's genes in a pattern called X-linked recessive inheritance..

• The defective gene that causes Duchenne and Becker's muscular dystrophies is located on the X-chromosome. Women who have only one X-chromosome with the defective gene that causes these muscular dystrophies are carriers and sometimes develop heart muscle problems (cardiomyopathy) and mild muscle weakness.

• In some cases of Duchenne and Becker's muscular dystrophies, the disease arises from a new mutation in a gene rather than from an inherited defective gene.

Treatment• There's currently no cure for any form of muscular

dystrophy. • Research into gene therapy may eventually provide

treatment to stop the progression of some types of muscular dystrophy.

• Current treatment is designed to help prevent or reduce deformities in the joints and the spine and to allow people with MD to remain mobile as long as possible. • Treatments may include various types of physical therapy, medications, assistive devices and surgery.

Pedigree Chart