Changes in DNA can produce Variation 5.2

DNA Variation Differences or variation in DNA are what makes us different from each other! Each human cell contains 46 chromosomes Each cell has 3 billion base pairs of DNA (wow!) Our DNA is 99.99% similar Of the 6 billion base pairs of DNA, only 5% are in the genes that code for RNA and proteins.

Errors can occur when DNA is copied UV light, X-rays, chemicals, etc. affect DNA Any change in DNA is called a mutation.

Types of Mutation Substitution – Exchanges one base for another. CTGGAG---- CTGGGG Insertion – Extra base pairs are inserted. CTGGAG---- CTGGTGGAG

Deletion- Section is lost, or deleted. CTGGAG -----CTAG Frameshift- Message is no longer read correctly. THE FAT CAT SAT --- HEF ATC ATS AT

When there is a mutation… Cells have different ways to repair mistakes Certain enzymes can proofread DNA such as correcting mismatched base pairs

When there is a mutation… The mutation causes no effect. Amino acids have more than 1 code Enough protein may be produced already The effect of a mutation is minor. Could affect skin/eye/hair pigmentation The effect of a mutation is great. Genetic disorder/disease

Genetic Disorders Sometimes passed from parents to offspring Sickle Cell Anemia Cystic Fibrosis (CF) Hemophilia Tay- Sachs Disease Huntington’s Disease (HD) Hypercholesterolemia Cancer

People Can Carry a Tendency for a disease Alzheimer's Emphysema Diabetes Cancer Their behavior can prevent it: Not smoking can prevent emphysema and many types of cancer

Treating Genetic Disorders Most genetic disorders cannot be cured, although progress is being made. Families who have a history of genetic disorders are recommended to undergo counseling before having a child. They can find out how it could affect their offspring. Some genetic disorders can be treated if diagnosed early enough, such as PKU (lacking a certain enzyme). If known, that child can be put on a certain diet and medicine routine.

Sickle Cell Anemia – chromosome 11 Mutation occurs on gene that codes for hemoglobin Hemoglobin – a protein that carries oxygen in red blood cells Mutation causes 1 amino acid to be replaced with another

It is a Recessive disorder Need 2 recessive genes to be affected (ss) Can be a carrier (Ss)

Provides protection against malaria and we still don’t know why

Modern Genetics and DNA Technology 5.3

Changes in DNA can change an organism Random changes in DNA can introduce new traits in an organism Humans can breed animals to get the certain traits they want. Ex: a cow that gives more quantities of milk

Selective Breeding Bloodhound – strong sense of smell The process of selecting and breeding parent organisms to pass on particular traits to the offspring. Breeders select desirable traits they want

Genetic Engineering A sequence of DNA from an organism is first isolated, then inserted into the DNA of another organism. The DNA inserted usually codes for a particular trait of interest GMO – Genetically modified organism

Genetic engineering can… Can make plants more insect resistant. Create crops suitable for areas with poor soil conditions

Genetic Engineering PROS CONS Food can be resistant to certain bacteria and pests. Reduces chemical pesticides Increases food production Add nutrients Possibly harmful to the human body but still unknown Could risk wild population like salmon

DNA Technology Can be used to produce new and better drugs for treating disease Determine the side effects of a drug on an individual Can be used to screen for and treat genetic disorders

Gene Therapy May soon allow scientists to correct certain recessive genetic disorders by replacing defective genes with copies of a healthy one. First step of gene therapy is to isolate a copy of the gene. Scientists are trying to input that gene into the cell by attaching it to a cold virus. Attempts in humans have not been successful. However, the outlook is promising.

DNA Identification Crime scenes – skin, hair, blood DNA profile – a DNA fingerprint Everyone different except identical twins!

Human Genome Project https://www.youtube.com/watch?v=PwdDa6QCDWw

Genome All the genetic material in an organism. The human genome project wanted to sequence all of the human genome (that’s a lot) We can then compare DNA across species We have similar genes to fruit flies and mice

Cloning A technique that uses technology to make copies. Can be applied to a segment of DNA or a whole organism Dolly 

Cloning Bacteria Place gene that codes for producing insulin That bacteria then replicates in large numbers Treats people with diabetes