Chapter 13

What is genetic engineering? Genetic Engineering = Using knowledge about genetics to create more desirable offspring.

Genetic Engineering in History Selective Breeding describes how humans have used knowledge about traits and genetic inheritance to breed desirable offspring. Example 1: If you want a dog that will retrieve things and act as a good guard dog, you could cross a Golden Retriever with a Doberman. Example 2: If you want a better type of corn, you could cross breed two types of corn so that the offspring tastes good and is resistant to pesticides.

Recombinant DNA All living things have DNA, and all DNA has the same structure. It is possible to cut and paste pieces of DNA from different species to give organisms more desirable traits. This is called recombinant DNA.

How does recombinant DNA work? A piece of DNA from an organism is selected. This usually represents some type of desirable trait. A restriction enzyme cuts that piece of DNA from the genome of the first organism. Then the genome of the second organism is cut open. DNA ligase glues the cut pieces together (“sticky ends”) to form a new piece of recombinant DNA.

How does recombinant DNA work?

Other Examples of Genetic Engineering Cloning A clone is a genetically identical individual Scientists inject DNA into an enucleated (nucleus removed) cell; then the cell is grown in utero First successful clone was Dolly the sheep in the late 1990s. Clones die at an earlier age and may experience disease, infection, or mutations Genetic Testing Technology currently used to identify diseases or disorders in fetuses or infants Genetic testing could increase discrimination

Other Examples of Genetic Engineering Stem Cell Research Stem Cells are unspecialized cells that can be grown in labs to replace damaged cells; this could cure many diseases and/or grow organs From umbilical cord blood and embryos (offspring in early pregnancy) Stem cells sometimes are found in adult skin, brain, etc. but they are not as successful as embryonic stem cells Resurrecting Extinct Animals Scientists insert DNA from an extinct animal into an enucleated egg from a similar descendant Example: Several years ago scientists tried to insert wooly mammoth DNA into an elephant

Other Examples of Genetic Engineering Genetically Modified Foods GM foods been genetically altered to fight off pests, have higher yields, have increased nutrition, improve food supplies etc. Could have mutations, could cause unknown allergic reactions. The U.S. does not require food labels to identify ingredients that may be GM Savior Siblings A savior sibling is a child who was purposely born to save the life of another family member by donating umbilical cord blood, blood, bone marrow, etc. Many countries require counseling and/or legal intervention if the donor child is underage

Other Examples of Genetic Engineering Transgenic Plants and Animals Transgenic means having genes from two or more species. Transgenic plants include GM foods while transgenic animals include animal hybrids (zorses, ligers, glow in the dark fish, etc) Designer Babies Genetic testing, in theory, could encourage parents to test for nonfatal traits such has hair color, eye color, etc.