Genetic Engineering Conceptual Biology Ch. 5.3

Vocabulary genetic engineering selective breeding hybridization inbreeding mutation transgenic clone inheritable genetic modification (IGM)

I. Manipulating Genetics Selective breeding = to only allow those with “desired” traits to pass on their genes Most farm animals and crop plants are from selective breeding Hybridization = crossing two dissimilar organisms to get the best of both Inbreeding = continued breeding of individuals with similar characteristics animal breeds are maintained by inbreeding (ex: dog breeds) chance for recessive genes increase (many breeds have genetic diseases from recessive alleles)

Selective Breeding of Wild Mustard

B. Increasing Differences Mutation = permanent change in a gene or chromosome usually harmful small % of mutations can be beneficial New Bacteria & Plants Scientists cause mutations in bacteria to try to get a useful mutation. Scientists cause mutations in plants so that they do not get sick as easily, grow better, have different colors, etc. Ex: bacteria that eat sewage or clean up oil spills

II. Genetic Engineering Transgenic Organisms In 1986, we inserted the gene which causes fireflies to glow with light into a tobacco plant. Transgenic organism = an organism that contains genes from another species Transgenics Transgenic bacteria Reproduce rapidly and are easy to grow Produce important substances for health and medicine ex: human insulin and human proteins

BioSteel = silk produced by goats from spider DNA used to make bullet proof vests Spider genes being injected into a goat's egg to produce a transgenic goat

Transgenic plants – major part of US agriculture; weed resistance, insecticides, vitamin enriched Transgenic animals – growth hormones in livestock, resistance to bacterial infections, production of human proteins

B. Cloning Clone = individual with genetically identical cells produced from a single cell Ex: an identical twin is a clone occurring “naturally” in the first days of an embryo’s development In 1997, 1st cloned mammal - a sheep named Dolly VIDEO NOTES 1) – 3) Successfully cloned cows, pigs, mules, cats, mice and other mammals 1st human cells cloned in 2001 (for use as stem cells)

Donor Nucleus Fused Cell Egg Cell Embryo Cloned Lamb Foster Mother These two cells are fused using an electric shock. Fused Cell Egg Cell The nucleus of the egg cell is removed. An egg cell is taken from an adult female sheep. The fused cell begins dividing normally. Embryo The embryo develops normally into a lamb—Dolly Cloned Lamb The embryo is placed in the uterus of a foster mother. Foster Mother

Cloning goals – make copies of transgenic organisms and endangered species, make advances in medicine like transplants that a body won’t reject and cloned stem cells

4. Cloning process A body cell is taken from the animal you want to clone. An egg cell is taken from a different animal. The nucleus is removed from the egg. The body cell and egg are combined by electricity. The new cell begins dividing, becoming an embryo. The embryo is implanted into a foster mother. The embryo develops into a cloned animal.

Cloning problems at this time Genetic errors - health problems Cloning techniques inefficient and difficult small % of DNA functions abnormally due to clones inheriting mitochondrial DNA from donor egg cell

Inheritable genetic modification (IGM) or “designer babies” A child whose genotype would be purposefully selected allows parents to weed out genetically defective embryos in the lab PGD involves screening embryos for genetic defects

Ethical implications – ability for parents to select for any preference, producing a custom designed infant Today - parents can choose gender Future – parents choose traits they want injected into the embyros in the lab Designer Babies Movie: http://www.pbs.org/teachers/connect/resources/5288/preview/