Inserting healthy genes into the genome to compensate for faulty genes Two techniques Ex vivo gene therapy Cells are altered outside of the body Ex Severe combined immunodeficiency syndrome SCIDs In vivo gene therapy Cells are altered inside the body Ex Cystic fibrosis Ex SCIDs Individuals lack adenosine deaminase ADA Enzyme needed to destroy toxins In absence of the enzyme toxins accumulate and impair development of T cells T cells are an important part of the immune system Prone to infections cancer Many children die by age 1 if not recognized Gene therapy and GMO s 1 Stem cells are removed from the red bone marrow A retrovirus is used as a vector to introduce the healing gene healing gene Uses reverse transcriptase to produce viral DNA which integrates into the genome of the stem cell Cells are then re introduced into the body First blood transfusions Second delivery of the ADA enzyme weekly doses Third White blood cells WBC removed functional ADA enzyme added and then returned to blood Now GT on stem cells in red bone marrow Gene therapy and GMO s 2 Ex Cystic fibrosis CF Autosomal recessive disorder Individuals lack a functional chloride channel Thick mucus accumulates in the respiratory tract Impairs pancreatic functions too p y Aerosol sprays are administered containing viruses which deliver the healing gene Helps to correct respiratory functioning but digestive enzymes must still be taken with each meal Somatic GT Non inheritable Germ line GT Germ line GT Alters DNA of egg or sperm or zygote Used to create transgenic organisms Gene therapy and GMO s 3 Important uses Plants resistant to herbicides Plants resistant to insects BT crops Gene from bacteria commonly found in soil Plants resistant to frost Corn soybean and cotton plants are commonly genetically altered In 2001 72 million acres of transgenic crops worldwide 26 of US corn crops were transgenic crops Resistance increasing in the target pest Exchange of genetic material between th t the transgenic plant and a related l t d l species t d i Concern about the impact of BT crops on nontarget species Gene is inserted into the egg that when fertilized will develop into a transgenic animal Current uses Gene pharming production of pharmaceuticals in the milk of farm animals the milk of farm animals Larger animals includes fish cows pigs rabbits and Mouse models the use of mice for various gene sheep studies Gene therapy and GMO s 4
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