DNA and Applied Genetics

Chromosomes & DNA All living things are made of cells. Nucleus All living things are made of cells. Cells contain a nucleus (control center of a cell) Nucleus contains chromosomes (X). Chromosomes are made up of DNA. Animal Cell DNA

DNA - deoxyribonucleic acid 1953 – Watson and Crick discovered the structure of DNA Basic substance of heredity It’s what makes up chromosomes Stores and passes on genetic information Watson & Crick – movie (4:04min)

Structure of DNA Looks like a twisted ladder – double helix Stairs = nitrogen base pairs A = Adenine T = Thymine G = Guanine C = cytosine A always with T G always with C Rails = sugar phosphate www.molecularstation.com

Structure of DNA Order of nitrogen bases determines genes Different chromosomes contain different amounts of genes. Change to the order = mutation Negative, Positive or Neutral Knowing which chromosome is affected makes it easier to identify the mutation.

DNA Replication Process: 1. 3. 2. Replication = process of making new copies of DNA. Occurs during interphase This is how mutations grow and/or get passed on: Body cells (Mitosis) – cancer Sex cells (Meiosis) – extra finger Process: 1. Ladder unzips between base pairs 2. Free floating bases pair up with original unzipped DNA. 3. Two exact copies are now created. 1. 3. 2. www.globalchange.umich.edu

Applied Genetics With the knowledge of DNA and genetics scientists have been able to apply the principles to medicine and agriculture. Plant and Animal Breeding Stronger, healthier, faster, smaller, taller Genetic Engineering New or better medicine Disease resistant and weather hardy agriculture Applied Genetics movie: 2:24min

Plant and Animal Breeding Selective breeding – process used to produce desirable traits. Used with both plants and animals. larger in size produce more food more resistant to diseases

Selective Breeding - Wheat Which wheat plant was selectively bred? What trait was selectively bred for? Why would this be a desirable trait? B Larger grain numbers per plant More crop per growing season A. B.

Plant and Animal Breeding Hybridization - Getting desired traits by combining two or more different traits. Use two genetically different but related species. Best traits of both parents Mule = female horse + male donkey.

Hybridization - Mule Can produce offspring with better traits than parents Stronger or healthier – hybrid vigor Vigor = strength or health. Mule: Advantages: more endurance than horse stronger than the donkey. Disadvantages: Sterile – unable to reproduce

Plant and Animal Breeding Inbreeding - Crossing of the same or similar sets of genes. Offspring will have same or similar traits as parents. Keeps breeds pure. Negative: Reduces an offspring’s chance of inheriting new gene combinations. evolution.berkeley.edu/

Inbreeding - Cheetah Disadvantages: cause organism to be more susceptible to certain diseases or changes in the environment. Cheetahs – almost all genetically identical Cheetah Range Map (Africa & W Asia) © www.pgoimages.com www.theanimalfiles.com

Plant and Animal Breeding Cloning - Used to make an animal that has the same nuclear DNA as another currently living or previously existing animal. not truly an identical clone of the donor animal. Only the clone's nuclear DNA is the same as the donor. Dolly was the first organism to have been cloned (sheep). www.crystalinks.com

Process of Cloning www.millerandlevine.com/

When Cloning Goes Wrong! http://www.dnaco.net