GMOs

What is a GMO?
It stands for Genetically Modified Organism. It is something whose genetic material has been altered in some way using genetic techniques. It gives an organism modified genes.
If I told you some genetically modified products were:
1. A fishy tomato. It is a tomato that is frost resistant. It is created by adding an antifreeze gene from cold-water fish to it. The tomatoes can now grow in cold, frosty conditions and they proved to be successful. This way, tomatoes stay good in harsher conditions and helps farmers gain more profit.


2. Tearless Onion. In Japan they discovered the enzyme that causes tears when an onion is cut. The gene was isolated which controls the production and now can be switched on and off.


3. Blue Strawberries. Dr. Elizabeth Davies and colleagues identified the gene that makes blueberries blue and injected it into the strawberry. The taste is still exactly the same except the berry is now blue.


Which one is the fake GMO?
The fake one turns out to be the blue strawberries. Nothing has been done with those; however, that does mean the fishy tomatoes and the tearless onions are real GMOs that have been created.
Most people will say there really isn’t a need for GMOs. Everything is the best in their natural state without any genes transferred.

•One of the GMOs that I studied more in depth in my class was the BT toxin genes. BT (Bacillus thuringiensis) is a soil bacterium which produces Cry (a protein that is toxic to insects). The toxins are meant to reduce crop losses to plant-eating bugs.
•Corn and cotton carry the Bt Cry gene. There has been a version in potatoes but it is not used anymore because restaurants and other people do not want to purchase transgenic potatoes.
•Risks involved with the GMO are with people who have fragile immune systems and acknowledging that the BT toxin can increase deterioration in the body.

Cloning

Use of human stem cells?
1. Research to gain understanding of complex events in human development
2. Research to test new drugs
3. Treatment or therapy to replace dead or damaged cells

The first animal to successfully cloned was Dolly the sheep


There are two types of cloning:
Reproductive-creating offspring asexually
Therapeutic-creates organs or tissue to cure diseases or treat injuries.

There are two methods in cloning
• Artificial Twinning using embryos (Blastomere Separation)
• Somatic cell nuclear transfer.

Risks Involved:
•High failure rate
•Large Offspring Syndrome (LOS)-Animals cloned are always larger and have to be born C-section usually.
•Abnormal gene expression patterns
•Decrease in length of telomeres

Pros for Cloning
•Production of animals models for disease study
•Production of stem cells
•Produce drugs from transgenetic animals
Agricultural Application
•Produce animals w/desirable traits
•Increase efficiency of livestock production
•Preserve endangered animals

Cons for cloning
•Decline in genetic diversity
•It is taking nature into their own hands
•Religious and moral reasoning
•Physical problems (birth defects)
•Possibility of mental and emotional problems of the clone



Do you think cloning is an acceptable thing to do? Will it ever fully be figured out? It is a complicated process that doesn’t have a high success rate.

Cystic Fibrosis

What is Cystic Fibrosis?
It is an inherited disease affecting the lungs and digestive system.
Mucous clogs the lungs, making it difficult to breath and leads to potential life-threatening infections.
•The disease keeps natural enzymes from helping the body break down food and absorbing the nutrients.
•The most common mutation occurs on the gene DeltaF508.
•People born with the disease typically live to their 30’s or 40’s which has increased significantly since research has been done.


Diagnosis:
•Most people are diagnosed by age two
•Roughly 1,000 new cases come about every year.



Inheritance:
•It is a recessive disease caused by mutation on chromosome 7.
•Heterozygous carriers of the gene with not show any affects. Two mutated genes have to be present for the Cystic Fibrosis to appear.
•Two unaffected parents that are carriers have a 25% chance of having an affected child.

Diagnosing
•Blood tests
•Sweat chloride test is common for determining if a person has cystic fibrosis. High salt level (salty tasting sweat)is a sign of the disease.
•Lung function tests

Symptoms (just a few)
•Slow growth
•May not have bowel movements in the first couple days of life
•Nausea and loss of appetite
•Weight loss
•Coughing/increasing mucous in lungs
•Nasal Congestion
•Sinus pain/pressure
Two people having the same mutation may have different symptoms because CF (Cystic Fibrosis) is influenced greatly by genetic factors.

Most kids are normal until they reach their adolescence or adulthood.
They are encouraged to participate in activities as normal until the disease catches up to them and they become disabled.

Population Genetics
About 1 in 2,500-3,500 newborn Caucasian Americans has this disease.
The genetic disorder can’t be prevented.
Some treatments can delay death including:
•Antibiotics
•Chest physical therapy
•Exercise
•Lung problems/possible transplant

Fragile X-Syndrome

Got that name because of its fragile appearance on the x-chromosome
Discovered in 1910 by Thomas Morgan
•It is the most common type of mental retardation inherited
•Normal life span for people who inherit the mutation
•Severity can range but it is typically more severe in males than females
•Anxiety and unstable mood with autistic behaviors


Inheritance
•X-linked recessive
•FMRI is mutated from too many copies of CGG in DNA. When repeats occur too much, FMRP (connects the nerve cells) doesn’t function.

•CGG normal repeats is 6-45 times
• Pre-mutation is 55-200 times
• Full mutation is 200-800 times.



CURE
•There is no cure. Genetic counseling is an option before getting pregnant. Speech and development therapies are available to make a person the most normal.

Percentages
1:2000 males 1:800 male carriers
1:4000 females 1:250 female carriers

Duchene Muscular Dystrophy- discovered in 1861

It is an inherited disorder that involves muscle weakness that continually worsens.

Symptoms-Usually appear early on in childhood.
• Progressive muscle weakness •Belly sticks out due to weak muscles
•Ability to walk worsens •Thin weak thighs
•Motor skills impaired •Starts to affect breathing and heart.
•Skeletal deformities

Life Expectancy is found to be teens to mid thirties

Diagnosis
Gene testing shows errors on Xp21

Gene Mutation
Lack of dystrophin protein
DMD is located on x-chromosome on Xp21 locus
It is an x-linked recessive gene. Boys are generally the ones affected.

Complications
•Congestive heart failure(rare)
•Deformities
•Irregular heart beat(rare)
•Mental impairment

Prevention and Treatment
•No cure
•Use steroids to treat
•Exercise helps and braces when they can’t walk as well. Physical therapy helps.

Familial Hypercholesterolemia-found on chromosome 19

It is a condition passed down through families when a person has high levels of “bad” cholesterol (LDL) in the bloodstream beginning at birth. It can cause heart attacks early on in life.



It is only necessary to get the abnormal gene from one parent in order to receive the disease. If a child is homozygous (received the gene from both parents) it is much more severe.


•Discovered in 1938 as Autosomal Dominant.
•There are high cholesterol levels. Chest pains and leads to heart disease.
•Increases risk of heart attack. Men=40-50 yrs old. Women=50-65 yrs old (if heterozygous)
•If homozygous then heart attacks are possible around 20-30 yrs old.
•If homozygous, LCL receptors remove cholesterol from blood but if a person is homozygous then they don’t really work
• PCR testing can be done to find out if a person has the disease.

•It is not a very common disease (heterozygous-one in 500 people).You can’t prevent the gene; however, you can prolong from getting a heart attack. Liver transplant is a possibility to help or have agents which help lower cholesterol levels.


Treatment
•Proper diet-decrease fat intake to less than 30% of the total calories each day.
•Exercise
•Medications
•Drug Therapy
•Possible surgery (liver transplant)

Phenulketonuria(PKU)-Autosomal Recessive

It is a rare condition when a baby is born without the ability to properly break down an amino acid called phenylalanine.

•there is a mutation in a gene which codes for the enzyme (PAH)
•It is found on chromosome 12
It is a recessive allele so therefore a person must have two copies of the allele in order to be affected by the disease.


Prognosis
•All states test for the disease within first two weeks of birth (Guthrie test & HPLC test)
•It occurs every 1 in 15,000 births.

Symptoms (if un-treated)
Mental retardation, seizures (if you don’t follow the diet)

Treatment-requires a diet low in phenylalanine
“diet for life”
Foods high in phenylalanine
-eggs, fish, seafood, milk, aspartame, sweeteners, meats
Mothers that are carriers should be on the diet while pregnant.
•Take supplements to replace nutrients
•As long as the diet is followed, development and life expectancy is normal.

Tay-Sachs Disease

The disease is a deterioration of mental and physical abilities. It is caused by a genetic defect in a gene inherited from each parent.



-severe genetic condition
Six months old=diagnosed. There are seizures and behavior changes. As progression gets worse (6-10 months), they lose motor skills and sight. Usually death by age 5
There is no cure or treatment for the disease. There are 16 cases in America every year.

Huntington's Disease-Autosomal Dominant

To the bottom, the brain of a person with Huntington’s disease (top) vs. a normal brain (bottom)



The nerves are slowly destroyed.
-Huntington’s disease (HD) occurs when there is a large amount of CAG codon repeats within the Huntington gene.
-The disease is located on chromosome 4 at 4p16.3
-It begins at middle age (30’s or 40’s) and can cause premature death.


Symptoms (just a few)
-Difficulty moving
-Can’t speak very well
-loss of physical coordination
It is most common with European Ancestry (5 in 100,000 people)
-There is no cure. The progress can’t even be slowed. There is research for a cure being constructed.
Treatment can reduce some of the affects.

Lifestyle-depending on the number of codon repeats, influences the lifespan of a person
In order to stay healthy for as long as possible
-Speech therapy
-Maintain physical activity
-Keep up proper nutrition
-adequate fluids

Cancer Types

Cancer with correct type
Carcinomas-Breast, Colon, Eye, Kidney, Lung, Pancreatic, Prostate


Sarcomas-Muscle and bone
This is a picture of Synovial Sarcoma which occurs most commonly in young adults. The causes are still unknown. Most cases develop in the leg region and the next most common is in the arm. It can be controlled through radiation therapy.


Melanomas-Skin


Lymphomas and Leukemia’s-Red or white blood cells.

Cancer

The following questions will give you a better understanding of Cancer…
1. True or False, Cancer is not one disease?
True. It is a group of related diseases. It is a genetic disease. All cancers are due to mutations in the gene. Cancer= abnormal division of cells. It is loss of normal growth control.
2. True or False, Benign tumors are never a threat to life?
False. They are rarely a threat to life but they can be if their growth interferes with function on vital organs in which they can be located.
3. What is the primary difference between benign and malignant tumors?
Benign (not cancer) grow locally and cannot spread. Malignant (cancer) cells invade neighboring tissues and enter blood vessels. Every malignant comes from benign but benign don’t always turn into malignant.


4. What is meant by the term metastasis?
Metastasis carries it through the blood stream and to other parts of the body.
5. True or False, Cancers may be inherited?
False. Some gene alterations are inherited however having the gene does not mean the person will receive cancer.
6. Identify three types of cells with respect to their pattern of division.
• Cells continually dividing.
• Cells that have stopped dividing but can divide when repairs are required.
• Cells that have stopped dividing and will not divide again.

There are two types of checkpoint genes.
• Go proteins-Oncogenes (there is too much acceleration and they can’t stop)
• Stop proteins-Tumor suppressor (genes taken break away)

Causes of cancer
50-80% of cancer is cause by lifestyle choices
1. Ionizing Radiation-high energy radiation that comes from the sun.
2. Non-ionizing radiation –ultra violet light (UV rays). Low energy SPF 30 is really the highest in sunscreen you need to go. Once past that it doesn’t really do anything else.
3. Chemical compounds-Tobacco use. There is a twenty year between smoking and cancer. (twenty year what?)
4. Viruses-HPV(cervical cancer) HIV(Aids) HHV8(Kaposi’s Sarcoma)
5. Bacteria-Helicobacter pylori-causes stomach ulcers. Leads to cancer
6. Heredity- Example is breast cancer patients.
7. Aging-the older you get, the more likely you will be to get cancer
8. Ethnic Population-colon cancer in the U.S, stomach cancer in Japan from seafood and alcohol, skin cancer in Australia.

Modes of Inheritance

There are various modes of inheritance for different mutations/diseases including:
•Autosomal Dominant-females and males are equally likely to have a trait. The trait does not skip generations. Affected children have one affected parent. There is a male to male transmission (meaning that if a dad has it, it is automatically passed on to the suns)
•Autosomal Recessive- males and females are equally likely to inherit the trait. It is known to skip generations. Children can be born to unaffected parents (who are carriers)
•X-linked Recessive-more often occurs in males than females. Generally known to skip one or more generations. Affected males are usually born to unaffected females (carriers)
Females who are affected must have a father that is affected or it has to be autosomal
There is no male-to-male transmission
•X-linked Dominant-twice as many females as males are affected. The mutation doesn’t skip generations. Generally females will pass the trait to half of their children. Sons and daughters are equally affected. All daughters of affected males are affected. There is no male-to-male transmission. Dad gives to 100% female and 0% to males.
•Y-linked-Only males are affected. All sons of affected males will be affected as well. The trait doesn’t skip generations.

What is this inheritance?


Autosomal Dominant!
It does not skip generations. Females and males are equally likely to have the trait. Affected children have one affected parent.

Inheritance

Inheritance
Gene-Simply part of your appearance. It is one unit that was inherited at conception. (Ex. The color of your hair)
Allele-an alternate form of a gene. (Ex. Red vs. non red)
Dominant vs. Recessive-Some genes are dominant and some are recessive. The dominant always cover up the recessive.
Homozygous vs. Heterozygous- Homozygous is where there are two of the same alleles. Heterozygous is two different alleles.
Genotype vs. Phenotype-Genotype is what is inside the nucleus. You can’t see what is on the inside but the phenotype is the physical appearance of a person.

Questions to think about…
When two black mice crossed together, produced black and white offspring what is the genotype of the parents? Hint: black is dominant

Answer: Heterozygous. Since there was a white mouse that means both parents had to be carriers of the white gene because white is recessive.



If bill is albino what is his genotype?

Answer: Homozygous Albino. The gene for Albino is recessive so
he had to receive that gene from both parents.

If Rex (doesn’t suffer from migraines) and Linda (who has them regularly) were to get married and have children, what is the chance of passing migraines on?

Answer: There is a 50% chance.
To determine potential offspring, it is best to do a punnett square crossing the different options for the alleles.
Example problem: Foxes, Gold coat is governed by a recessive allele g and red color by a dominant allele G. Determine the genotypic ratios from the following mating.



By looking at the punnett square, we can conclude that the genotype would be 25% homozygous dominate and 50% heterozygous and 25% homozygous recessive. 75% of the foxes would come out Red dominant and 25% would come out gold recessive.

X Linked- only appears on the X chromosome
Y Linked-only appears on the Y chromosome. Never will be in females. It is hemizygous and passed from father to all sons.
Sex Limited- the trait is on the autosomes and is only found in one gender.
Sex influenced-on the autosomes. It occurs in both genders but is dominant in one over the other

Chromosome Disorders

1.The term that means an extra or missing chromosome is Aneuploidy.
2.An example of an aneuploidy is Down syndrome.
3.A section of chromosomes gets turned around, reversing the order of the genes is Inversion.
4.Term that means identical twins is Monozygotic.

Aneuploidy
•Caused by nondisjunction during meiosis.
•Nullisomy (2n-2): Missing both copies of one chromosome
•Monosomy (2n-1): Missing one chromosome

Polyploidy-having more than two sets of chromosomes.
•Causes
-errors in meiosis: results in diploid gametes
-events at fertilization: dispermy- two sperm cells penetrate and fertilize the egg.

Human Chromosome Disorders
Monosomy
Missing one chromosome from a pair
•Rare in live births
•turner syndrome (45, x): xo female. The female is missing an x chromosome
•causes-nondisjunction in meiosis or mitosis




Notice in the picture that the last chromosome only contains one allele when it should have two.


Trisomy (more common than monosomy)
Trisomy is an abnormality in which there are three copies, instead of two, of chromosomes. It is a type of aneuplodiy
•13 (Patau Syndrome)
-cleft palate, eye defects…
•18 (Edward Syndrome)
-small birth weight, slow growth
•21 (Down Syndrome)
-translocation of chromosome 21 (usually)
• Deletion of chromosome 15
-Cri-du-chat & Pradar-willi syndrome
Translocation (one piece changes play but the other doesn’t. It is deletion)

Meiosis!

Meiosis is defined as cell division in sexually reproducing organisms that reduces amount of genetic information by half.

Meiosis: There are two stages of meiosis that occur. In the first stage it starts out with a random alignment between the female chromosomes and the male chromosomes. In the anaphase stage, the sister chromatids, (two identical copies of a single chromosome connected by a centromere), stay together and the homologous chromosomes, (a pair of complete chromosomes), separate.

During meiosis one there is a crossing over, which is where the mother and father’s chromosomes are mixed creating a child’s DNA. (Ex. Blue eyes brown hair or brown eyes and blonde hair)

In the end of Meiosis one, chromosomes consist of two chromatids (one of two identical copies of DNA)

http://www.macroevolution.net/images/sister-chromatids-275.jpg

http://mrskingsbioweb.com/images/cell.h1.jpg

Meiosis two: There is no crossing over in Meiosis two. Meiosis two only happens when the egg is fertilized by sperm. In the end of Meiosis I there are two haploid cells, which by the end of meiosis two will be divided into four haploid cells. The four main steps as seen in this picture are prophase II, Metaphase II, Anaphase II, and Telophase II.

In prophase II there is a shortening and thickening of the chromatids. In metaphase II, the plate is rotated by 90 degrees so it is horizontal instead of perpendicular. In anaphase II, the sister chromatids are pulled apart. They are now referred to as sister chromosomes and move to opposite poles. Finally in telophase II, four daughter cells are produced, each having a haploid (contains one complete set of chromosomes) set of chromosomes. Meiosis is then complete.

http://www.biology.iupui.edu/biocourses/n100/images/meiosis2cropped.jpg

In planning what to put in this blog, I decided that it would be the best for myself and the people reading if I illustrated the points that I learned the most from. I picked quite a few but definitely not all of the topics that stood out to me. This class has taught me so many things that I have never realized before about DNA.