Inherited Diseases and Mutations

Deoxyribonucleic acid Genes are made out of DNA or deoxyribonucleic acid. DNA is a chemical language that makes each of us unique.

Replication….. When DNA copies itself it is called replication. Sometimes when replication takes place a mistake in the sequence of DNA is made Entire sections of DNA can be deleted or added in where they don’t belong

Two processes that involve replication…

Meiosis: A process in which gametes (sex-cells) are Formed. Egg = female gamete Sperm = male gamete each gamete carries half of the genetic information from The parent organism

a mutation in one of these which is passed on to the 23 Humans have 23 pairs of chromosomes Sometimes there may be a mutation in one of these which is passed on to the Offspring.

Interesting fact: may not replicate normally Females are born with All of the eggs they will have During their lives. Males produce sperm beginning In puberty and continuing througout life. Down Syndrome is more common In children born after a woman’s 40th Birthday. The eggs are 40yrs old and may not replicate normally

Mitosis A process of cell division that makes an organism grow. How is that different from meiosis? During both of these processes it is possible for mutations to occur. Cancer is mutated cells that are able to replicate.

Let’s take a look at a few examples of mutations

Mutations A mutation occurs when DNA changes Most mutations are not harmful…. Sometimes mutations can give an organism an advantage…. Most mutated cells die Some however can cause disease or disorders in humans (4000 in humans)

well just a little maybe! Harmful?.....not at all! scary… well just a little maybe!

Mutagens Substances that are known to cause mutations…………

Cigarette smoke

Healthy lung vs. smoker’s lung

Sun…..skin cancer

Skin cancer

Melanoma

Radioactive material

Chernobyl… a Russian nuclear power plant that had a melt down

Children were born with birth defects due to the exposure of the gametes to radiation

Children suffer from cancer related diseases Cancer in children has increased dramatically in the Ukraine and Bellarusse after the Chernobyl disaster. According to WHO, cancer of the thyroid glands has increased 100 times. Studies by Professor Juri Zozola, of people that lives in radioactive areas, have proven that even small doses of radiation effects the brain and eventually cause diseases. Professor Zozola is deeply concerned about these results which indicate that the number of currently diagnosed people suffering radiation related disease is only the top of the iceberg. That radioactive exposure to girls and fertile women involve consequences to their genes and reproductive systems is certain.

The female gametes were affected and therefore the children born were also affected. A female has all of the eggs she will have for her entire life when she is born. Unlike males who don’t produce sperm until later.

Pollution… just another mutagen!!!

Can mutations affect offspring If a person smokes cigarettes and gets lung cancer, can they pass lung cancer on to their children? What about if a person gets skin cancer from laying out in the sun without using sunscreen? The only mutations that can be passed on to children are mutations that affect the sex cells or gametes. If a person is born with a condition….yes, they can pass it on. If a person is exposed to radiation in an amount large enough to affect their gametes…yes, they can pass it on to their children. (example: Chernobyl)

Inherited diseases Most diseases are caused by the effects of inherited genes Even though the difference between the DNA sequence can be small, some serious and even fatal diseases can be caused. Recessive genes cause most inherited diseases. If a person has one recessive allele, they are a carrier of the condition, but do not have the condition themselves. If a person has two recessive alleles, they have the condition.

Lets look at some inherited diseases

Cystic fibrosis About 1 in every 2000 children born in the united states have cystic fibrosis This disease causes a thick mucus to clog the airways and the lungs. Bacteria grow in mucus and destroy the lungs. Carried on chromosome #7 Caused by a recessive allele

Infected lung normal lung

Treatment Breathing treatments to clear the lungs “clapping” the chest or back to break up mucus and expel it Coughing to expel the mucus Life expectancy has improved because of new treatments

Sickle Cell Anemia Caused by a recessive allele 1 in 500 children born with this condition

More common among African Americans but anyone can be born with sickle cell

Irregular shaped red blood cells that carry less oxygen….. Take up space in the blood.

it has to work harder because Overworks the heart… it has to work harder because some of the cells it is working to pump around are not working the way they should

TREATMENT There is no cure for this disease Medicines can be taken to help with infections Blood transfusions can be given

Achondroplasia Condition in which a person is far below the normal size. Caused by a dominant allele Limbs are shorter than normal Possible to have normal sized children

Albinism Condition caused by a recessive gene Inability to produce pigment in some or all organs resulting in abnormally light skin, hair. Eyes are usually red because the iris lacks pigment. Can be found in other animals