Modifying Genes How can they be changed?

1. Genetic Engineering Replacing genes for desired traits… ◦ Must know exact location  Gene map (genome project) Example 1 : ◦ Cloning: Identical copy of gene or entire organism  Organ transplants  Organism can have genetic disorders/health issues

Dolly the Sheep First cloned mammal (from a mammary gland), 1997

1. Genetic Engineering Example 2: ◦ Gene Therapy  Normal gene inserted to abnormal or absent gene location  Host often rejects new foreign material

1. Genetic Engineering Example 3: ◦ Stem cells: Undifferentiated – can become specialized (become any type cell) ◦ Embryos & adults ◦ Can replace damaged tissues

February donor eggs --> 30 blastocysts --> 1 stem cell May donor eggs --> 31 blastocysts --> 11 stem cells 10 donor eggs fused with skin cells from 9 patients with spinal injuries & 1 with diabetes all formed embryonic cell layers and each was compatible with patients immune systems and was genetically matched to donors.

1. Genetic Engineering Goals: ◦ Plants: Resist insects, more nutritious, keep longer ◦ Animals: Bigger, grow faster, disease resistant ◦ Bacteria: Produce insulin or growth hormone ◦ Humans: Replace mutant genes (Tay-Sachs, CF, Sickle Cell Anemia) [in theory]

2. Selective Breeding Method of artificially selecting and breeding only organisms with a desired trait to produce the next generation. Most all domesticated animals and most crop plants

2. Selective Breeding Hybridization: Combining two desired traits of an org. into one generation Usually between two diff (but similar) species.

Plant breeders can cross a large yellow pepper and a small red pepper to create a hybrid that is large and red. In this case the traits for size and red color are dominant (yellow is a recessive trait). Traits like nutritional levels operate under the same laws, but are far more complex to work with.