Chapter 13

What is genetic engineering?Genetic

Engineering = Using knowledge about genetics to create more desirable offspring.

Genetic Engineering in HistorySelective 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 DNAAll 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 EngineeringCloning

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 EngineeringStem 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 EngineeringGenetically 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 EngineeringTransgenic 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.