Before continuing, ask yourself, “How do I evaluate media currently, how do I know if they are reliable?” Got it? Great lets continue. As you just though about your own personal criteria and rules for evaluating consider many of these helpful hints in evaluating media especially pertaining to science.

• Don’t always take everything on the internet as truth. Many sites may be popular and helpful in some things but always be willing to analyze that information on your own. Wikipedia is a great example of this. Do you use it?  Many professors,  doctors, and other people regard Wikipedia as an unreliable source, but in reality most people use it, even those professors opposing it. I agree it can be erroneous, but can also put things in simple understandable terms. Wikipedia may be a fine source as long as there are other supporting sources, also try finding the reference material it gives and read that. Don’t depend on Wikipedia. When it comes to your health use another source that is well known and very reliable.

• When reading articles look for its reference to being a peer reviewed journal. This means what ever the claim was other professionals and scientists have been able to replicate and validate the claim.

When evaluating ask yourself these questions:

• Who is reporting the results? Is it a reliable source of medical news? Always verify it through your healthcare provider.
• Who or what was the study based on: laboratory, on animals, or on people? This indicates what it will mean to humans and the stage of development.
• How extensive was the study? Just a rule of thumb, the larger the study the better the data.
• Does it include people like you? Will it have any affect on you or others you know or does it mean nothing?
• Are the results easy-to-understand? Once it was described if you can’t explain it to a child you don’t understand it completely yourself. The same applies to these claims, if they are very hard to understand they may need some more studies.
• Where was the research done?  Medical professionals and scientists at a medical school or large hospital, that have much experience and resources may be able to give you an idea of how valid the claims are.

This is a brief list of things you may add to it, but remember don’t believe everything you hear or read, be your own judge. Always consult with your healthcare provider if there is ever a question. Good luck.

The mom has two X chromosomes (XX), the dad has one X and one Y, (XY). The mom will always give a X to her offspring but the dad is the wildcard he could give a X or a Y. If both parents give an X, (XX) the child will be a girl. If  the dad gives a Y instead of an X  and the mom gives her X (XY) then the child will a boy.

• XY=Male
• XX=Female

This actually happens in the fourth week of development at the Sex-determining Region Y (SRY) gene. The embryo develops near the kidneys called the genital ridge, three genes on autosomes kick in to convert the genital ridge tissue into tissue that can become a sex organ.

So knowing a little about the sex, we can understand a little about sex chromosome linked traits:

• X-linked Traits – those that come from genes from  X chromosome. These effect sons more than daughters.
• Y-linked- Traits that are passed from father to son. For example baldness.
• Sex-limited Traits – in both male and female, but it is only expressed in one sex, usually males.
• Sex-influenced Traits – The phenotype depends on the sex of the individual carrying the affected gene.

You have heard that baldness comes from the mother’s side, is this true?

Sometimes it is true. It can come from both the father and son. Most people recognize it when the father has hair and the son loses his hair, they assume it is from the mothers side. But many times they don’t acknowledge the fact that more commonly it is father and son that are both bald.

There is much more to be said about this, in the future we will continue the discussion.

• Physical exams
• Imaging studies
• Lab tests
• Pathology reports
• Surgical reports

If by chance you or someone you know has been diagnosed with some type of cancer below are some of the most common and classical treatments for cancer:

• Radiation Therapy
• Chemotherapy
• Surgery

Below are explanations, examples and side effects of each type of therapy.

Radiation Therapy

Radiation Therapy is a treatment that creats so many mutations in the DNA that the malignant cells stop functioning and die. Unfortunately, like all treatments this is hard on the body and especially the emotions of patients. Some side effects of radiation therapy include:

• Fatigue
• Red, dry and itching skin
• Inflamed dry mouth with loss of taste
• Increased risk of cavities in teeth

Chemotherapy

Chemotherapy is a treatment that uses drugs to target the cancer, other names of chemotherapy are antineoplastic therapy and cytotoxic therapy. Mustard gas was first used for chemotherapy.
Side effects of chemotherapy:

• Hair loss
• Weakened immune system
• Stomach ulcers
• Digestive problems
• Anemia

Surgery
Surgery is probably the simplest and quickest form of cancer treatments. It is primarily used for skin cancers and other tumors that are easily reached. It typically doesn’t have many side effects other than fatigue.

Before resorting to treatment hopefully we are accoutable to ourselves and use simple prevention techniques such as:

• Avoid tobacco
• Eat anti-oxidants found in red, organe and yellow vegetables
• Have a diet rich in fiber will reduces risk of colorectal cancer
• Avoid sunbathing, it increases risk of developing skin cancer

Carcinogens

Carcinogens are chemicals or other particulates that increase the development cancers.

• Arsenic
• Asbestos
• Benzene
• Radon

Avoiding Skin Cancer

Literally here are the ABCD’s of avoiding and preventing skin cancer:

• Asymmetrical shape
• Border irregular-
• Coloration- darker colors
• Diameter larger than a pencil eraser

If it looks weird it probably is.

You may be familiar with some of these cancers causing agents, some get more publicity than others:

• Chemicals compounds
• Ionizing an non-ionizing Radiation
• Viruses and Bacteria
• Heredity
• Diet and Obesity
• Age

Here is an interesting fact:

• Skin cancer is higher in Dallas than in Detroit.
• The UK has one of the highest lung cancer rate.
• China is known for having liver cancer.
• Australia has the highest skin cancer rate.
• Japan has more stomach cancer
• the US has many problems with colon cancer.
• Canada has many patients with leukenia.
• Brazil has a lot of cervical cancer.

Why? Why do each of these different geographic locations have higher cancer rates than other parts of the world? It could be highly due to behavior and culture. You see there are many factors that we can’t avoid and there are some that we can. So in summary, what causes cancer? It could be a number of things and maybe even a combination, but usually will come from heredity, behavior (culture), and other factors mentioned above.

Interesting fact: 80% of all cancers are determined to be carcinomas.

Staging

Cancer is refered to in stages, as to its severity, growth, and spreading.

The staging rules are simple: TMN and then they will be on a 4 point scale 4 being the worst and X meaning unknown.

• Tumor- how big is the tumor
• Matastasize- has it spread
• Node- has it reached a node

For example,  T4M3N0, this means that it is a large tumor that has matastasized but it hasn’t reached regional lymph nodes.

1. Cancer is not one just one disease as many believe. Cancer is a group of related diseases, that occur through much of the same process.
2. There are two types of tumors malignant and benign. Most know that malignant tumors are the live threatening tumors because they have metastasized. Benign tumors are rarely life threatening, but if their growth interferes with the function of a vital organ then it may become a problem.
3. As mentioned above malignant tumors have metastasized, meaning that they have spread to other areas of the body, whereas benign tumors are centralized. If the tumor spreads to different nodes then it becomes very difficult to stop, but other tumors are still able to be treated as we will discuss later.
4. Have you ever heard that cancer is inherited? Well, some gene altercations are inherited from parents, this doesn’t mean the person will easily develop cancer; but it does mean that the chance of cancer is increased.
5. Most people know this but, cancer is not contagious. No matter what people think, it’s not, so be nervous.
6. To understand cancer and its development better we need to know that there are three types of cells:

• Cells that are continually producing.
• Cells that divide and reproduce when needed.
• Cells that once produced will never divide again.

This is important to know because in a cell there are oncogenes, which are always reproducing and if mutated can lead to tumor growth, and tumor suppressor genes which stop cell reproduction. They maintain and control the cells behavior but when one is mutated it throws the whole system off making tumor growth.

So there you have it a little basic knowledge about cancer, now you can understand the doctor better.

three different cells

The following is from a heredity class (Bio 176) given at Brigham Young University- Idaho.

A single strand of DNA is far too small to see or read even with powerful microscopes it would be like trying to distinguish a single strand of hair on a person sitting on the other side of a large lecture hall.  Still even at a distance you would be able see a whole head of hair and could probably identify its length and color.  Likewise we can detect and observe DNA when it exists in a sample of millions of similar copies.  That is one of the reasons PCR is so useful.  Scientists can start from a very small undetectable sample and through PCR make enough copies of that sample to be able to observe and utilize it in other applications.

The second reason PCR is so popular is because it gives scientists a way of pulling out very specific regions of the DNA that they are interested while leaving the rest behind.  Imagine you are going to a new restaurant across town in an unfamiliar area.  You might want to take a small foldable map of the city or even a single page printout from Mapquest. You certainly wouldn’t want to go down to your local library and checkout the 2000 page atlas on world geography.  Even if it did contain the information you needed it would be too big and cumbersome and difficult to sort through to find the information you want.  Most scientists will spend their whole careers studying less than 5000bp of the 3.2 billion bp human genome.  PCR gives scientists a way of targeting and pulling out just the regions that they are interested in and leaving the rest behind.
In our own class understanding PCR is important because it is the foundation technique for DNA fingerprinting, genetic disorder testing, gene cloning, and genetic genealogy each of which have their own lecture days.  It is also useful background in a variety of other lectures and discussions.  Below are just a few case studies of how PCR might be used.
Cloning and gene therapy.  Increasing numbers of people today are using insulin as a means of controlling their diabetes.  Historically medicinal insulin was isolated from pig and cow blood at slaughter houses but the yield was often low, costs were high, and there was a real fear of disease contamination.  Today researchers can use PCR to amplify the gene for human insulin.  The billions of copies provided by PCR can then be used to clone the gene into yeast which then use it to produce human insulin.  The artificial human insulin can then be affordably produced in large culture vats with little or no risk of disease contamination.

Diagnosing genetic disorders.  In another application PCR can be used to amplify and sequence the gene for a critical enzyme from the DNA of new born infants.   Looking at the sequence doctors can identify mutations that lead to a treatable disorder called phenylketonuria which leads to improper development and brain damage if not diagnosed early.
Identifying criminals.  Forensic scientists use PCR to amplify highly variable regions of DNA from crimes scenes and suspects.  Each individual produces a unique pattern of PCR generated fragment sizes that can then be used to link a particular suspect to a crime or in some cases prove their innocence.

So to understand how scientists analyze DNA they need PCR so they can actually see what they are doing

• Genetic regions- Region that contains genes of cells.
• Genes- Short sequences of DNA that carry the sequence information to make the many proteins needed by the cell.
• Regulatory Regions- Short sequence of DNA
• Expression- Means to turn on a particular gene.
• Junk region- Part of the chromosome that have no apparent function
• Satellite regions- Regions that exsist between genes and introns which exist in a gene.
• Uncondensed form- Chromosome is spread out all over the nucleus. Most chromosomes are uncondensed.
• Condensed form- Before cell starts to divide the DNA starts to coil and pack, they condense to avoid breaking or losing pieces as they move to opposite sides in cell division.
• Karyotype- A process to prepare a cell to allow us to count and compare chromosomes.
• Homologous Chromosomes- Chromosomes that make up a pair. They are similar, but not identical. Same length, same karyotype banding patterns, same genes but not the same version. Everyone has 23 chromosomes with copies.
• Alleles- Different versions of a gene, normal or mutated
• Diploid- Cells that contain two sets of chromosomes. Almost all animals are diploid.
• Haploid- A cell with only one set of chromosomes.
• X chromosome-Chromosome given from the mother and father. XX is a female
• Y Chromosome- Chromosome only given by the father, indicates a male. XY is Male.
• Sex chromosome- X and Y chromosomes.
• SRY gene- One gene on Y chromosome that acts a a master switch for turning on all other genes that lead to male development.
• Autosomal Chromosomes- All other pairs of non-sex chromosomes.
• Telomeres- Two ends of a chromosome.
• Replication- Process of copying the DNA in each chromosome.
• Meiosis- special form of cell division used to form the eggs and sperm then combine to form a new embryo.

Well, there you go a lot of words but it will help you understand if we mention any of these words.

Here are some interesting facts:

• You have 2 copies of all your chromosomes. Chromosomes carry the genes and the genes may be different versions.
• Each person has two sets of 23 chromosomes making 46.
• All genders have an X Chromosome.  XX is a female and XY is a male.
• You know all those investigation shows on TV? When they do all those test with Karyotypes by testing the blood cells and finding if it is the same person.
• Down Syndrome is when Chromosome 21 has three copies.

Process of Meiosis: You first start with one diploid cell.

1. Interphase
2. Meiosis 1- crossover, random alignment, split homologous pair.
3. Meiosis 2- Split duplicated chromosomes.
4. This results in four haploid cells.

Well there you have it for a now, you now know a little more about how mothers and fathers transfer their genes and chromosomes to their children.

If you are from a family that has had the same gentic disorder for many years and you are planning on having a child soon, find out if you or your partner has andy genetic disorder and genetic counselors can help with planning to have a successful birth.

Many of the tests are basic ones that most are familiar with, such as:

• PET scan
• Cat Scan
• Prenatal screening
• Blood tests
• Others

Your family will be much happier knowing how to deal with a disorder and living a great life, rather than cutting a life short. Many times disorders can be genetically helped by in vitro fertilization, when genes are manually altered and assured not to have the adverse affects. Make sure to consult with your doctor in each and every case, they want to help.

When using a pedigree you need to know who the proband is, it is the person who has a trait, disorder, or who you are studying. Below are some of the definitions of symbols used in pedigrees.

• An open circle indicates an unaffected female. A solid square is an affected female.
• A solid square is an affected male. An open square is an unaffected male.
• A circle or square with a diagonal line drawn through it means a deceased individual
• A vertical line connecting a square and a circle means parents of a child

Generations are resembled by Roman Numerals and numbers represent which person in that generation. There are five primary modes of inheritance.

• Autosomal dominant
• Autosomal recessive
• X linked dominant
• X linked recessive
• Y linked

The below information was used in a BYU-Idaho heredity class. Give it a try and see if you can figure it out!

Paul and Diana have seven children.  Two boys and two girls have four of the same medical problems – obesity, deafness, loss of central vision, and diabetes mellitus.  Paul has a brother Ralph, married to Alice, and they have two daughters.  Diana has a sister, Wendy, married to Joe, and they have three boys, Tom, Steve, and Russ.  Paul’s parents are Michael and Sandra; Diana’s parents are Frank and Bertha.  Frank is Michael’s brother.  Paul and Diana’s family doctor thinks that the four children with the symptoms – George, John, Becky, and Tabitha – have a genetic disorder called Alstrom syndrome.

Using the above information construct a pedigree.
Even though we didn’t discuss modes of inheritance in detail, if you are feeling brave try to determine the most probable mode of inheritance for this inherited disorder.

Mendelian Inheritance

Briefly, we will explain what his law is all about, this will help you understand upcoming posts on heredity. Mendel crossed white flowers and purple flowers and the result was not a blend. Rather than being a mix of the two, the offspring flower was purple. Mendel then engeniously came up with the idea of “factors”, one which is a recessive characteristic and the other dominant. As time developed factors, were eventually referred to as genes. Mendel later concluded that the dominant gene, hides the recessive gene. After Mendel finished his experiments, he found that genes can have three different pairs for each trait: AA, aa, and Aa. The capital “A” represents the dominant gene and lowercase “a” represents the recessive gene. Although Mendel did this with plants the same applies to humans.

Just a little more information on how all this works and you will understand the basics of inheritance.

• Genes are inherited factors that determines some trait.
• Traits are individual characteristics determined by genes.
• Alleles are genes in different forms, they determine the phenotype (physical trait) used.
• Dominate traits require only one allele out of two alleles from the parents.
• Recessive traits require two alleles that are homozygous
• Homozygous indicates that both alleles are identical in form. (AA or aa)
• Heterozygou means that both alleles are different in form. (Aa)
• Phenotype is a gene responsible for a physical trait.
• Genotype is a combination of alleles with various genes.

Think about yourself with these:

• Thumb extension:  straight thumb is dominant, hitchhikers thumb is recessive
• Earlobe: Detached ear is dominate, attached is recessive.
• Ability to roll one’s tongue: Can roll is  dominate, can’t roll is recessive.
• Dimples and freckles are dominate
• Hairline: a widows peak is dominate, a straight hairline is recessive.

You may observe traits in individuals that share a commonality with parents and/or  family members. Knowing this now you can figure out probabilities of what different combined traits will produce. This is done with a Punnet Square, a 2 x 2 matrix that shows probabilities.

Go to this website to try out your knowledge and understanding of inheritance.