Mutations

• 1. Mutation – Changes in genetic material• 2. Gene mutation – changes in a single gene Chromosome mutation – change in whole

chromosome 3. Point mutation – a gene mutation involving

one or a few nucleotides.

Point Mutations – changes in one or a few nucleotides

Chromosomal Mutations – changes in the number or structure of

chromosomes

Mutations - Most neutral

• 8. Most mutations are neutral – they have little or no effect on the expression of genes or the function of proteins.

Mutations – Some harmful9. How are mutations harmful?

They can cause defective proteins to form which disrupt normal biological activity. They can cause genetic diseases and some types of cancer.

Leukemia is an uncontrolled proliferation of one kind of white blood cell (or leukocyte).

Benefits of Mutations• 10. How are mutations beneficial?

They cause genetic variation in a species. Proteins that are new or altered can be useful to organisms in different or changing environments. This is one factor in the evolution of a species.

Polyploidy

• 11. Polyploidy – condition in which an organism has extra sets of chromosomes.

Polyploidy Plants• 12. Polyploidy plants are often larger and

stronger than diploid plants

Polyploidy in humans

• Polyploidy is not beneficial to humans!• Down syndrome• Klinefelter’s syndrome

Genetic Technology

Power to Predict Power to Choose

Power to Manipulate

A Perfect Family?

Designer babies

Ethics Clip

Genetic Technologies• Genetic Testing• PGD – Preimplantation Genetic Diagnosis• Cloning• DNA Databases/DNA Fingerprinting• “Savior” babies• “Designer” babies/ IVF• Genetically modified animals and plants

Ethical Questions

• Should we use our powers?• For what purpose?• Should there be limitations?• What are the possible consequences? - Socially? - Economically? - Environmentally?

13-1 Changing the Living World

• 1. Selective Breeding – method of improving a species by allowing only those individual organisms with desired

characteristics to produce the next generation2. Purpose – taking advantage of naturally occurring genetic variation in

organisms to pass desired traits on

Selectively bred Hybridization/Inbreeding

• Animals: horses, cats dogs, pigs, cows

• Plants: potatoes, corn, tomatoes, oranges, apples

Hybridization

5. Crossing dissimilar individuals to bring together the best of both organisms.

6. Ex: Burbank combined the disease

resistance of one plant with the food-producing capacity of another –Russet Burbank potato. He also hybridized the Shasta Daisy

Hybridization – Interesting Facts

• Today, somewhere around 99 percent of U.S. corn is grown from hybrid seed.

• Fungus resistance• Early maturity• Heat tolerance

Inbreeding7. Breeding of individuals with similar characteristics8. Ex: Dog Breeding – Poodle, Golden Retriever

9. Risks of inbreeding – since most members of a breed are genetically similar, there is a chance of bringing together two recessive alleles – genetic defect. Ex: blindness, joint deformities in German shepherds and golden retrievers.

Inducing Mutations

• 10. Breeders might induce mutations to increase genetic variation in a population that might produce mutants with desirable characteristics that aren’t found in the original population

• Since the 1950s, over 2,000 crop varieties have been developed by inducing mutations to randomly alter genetic traits and then selecting for improved types among the progeny. Ex: Ruby Star red grapefruit

Inducing Mutations – How?

• 11. Mutations can be induced by using radiation and chemicals

Bacteria - mutations• 12. Bacteria are useful when producing

mutations because their small size enables millions of organisms to be treated with radiation or chemicals at the same time. This increases the chances of producing a useful mutant.

• 13: Ex: oil-digesting bacteria

Polyploidy Plants• 14. Polyploidy Plants are produced by using drugs

that prevent chromosomal separation during meiosis.

• 15. Polyploidy Plants are desirable because they are often stronger and larger

Manipulating DNA

• Genetic Engineering- making changes in the DNA code of a living organism

• Biologists are now able to rewrite an organism’s DNA• No longer limited by the • variation already in nature

Tools of Genetic Engineering

Perform the following tasks:• DNA Extraction• Cutting DNA• Separating DNA• Reading the Sequence • Making Copies • Recombination

DNA Extraction

• DNA Extraction Cells are opened andthe DNA is separated from The other cell parts

Cutting DNA

• Cutting DNA – restriction enzymes• DNA molecules are too large to be analyzed • Each restriction enzyme cuts DNA at a specific

sequence of nucleotides

Separating DNA

• Gel electrophoresis (Virtual Lab)• Mixture placed at one end of a porous gel• Electric voltage• DNA has (-) charge• Migrates to (+) end• Smaller DNA – faster• Compare genomes• Locate genes

Reading the Sequence

• Reading the Sequence • Single strand of DNA with unknown sequence added to

test tube• DNA polymerase, A T C G• Makes one new DNA strand • Chemical dyes – tags• Gel electrophoresis• Order tells sequence of bases• Study of specific genes, compare genes w/other

organisms, learn functions of genes

Making Copies

• PCR Polymerase Chain Reaction• PCR Song GTCA• Primers – a place forDNA polymerase to start• DNA heated – strands separate• Cooled • Makes copies between primers• Copies also serve as templates • Millions of copies easily

Cutting and Pasting

• Recombinant DNA – produced by combining DNA from different sources

• Cell Transformation – cell takes in DNA from outside the cell. This external DNA becomes a component of the cell’s DNA

• Plasmid – small circular DNA molecule in some bacteria