Genetics - Cloning

®    Clones are organisms that are exact genetic copies that come from only one parent cell

®    Cloning in nature

o   Through asexual reproduction

o   Natural clones or identical twins occur in humans and other mammals

o   Twins are produced when a fertilized egg splits creating two or more embryo that carry almost identical DNA

o   Identical twins have nearly the same genetic makeup as each other, nut are genetically different from the parent

®    Reproductive cloning

§  Defined as the deliberate production of genetically identical individuals

§  Involving the implantation of a cloned embryo into a real or artificial uterus

o   Somatic Nuclear Transfer

§  Creates a viable embryo from a body cell and an egg cell

§  Involves taking an enucleated egg cell and implanting a donor nucleus from a somatic (body) cell

o   Embryo Transfer

§  Embryo is produced through IVF

§  Fine glass needle is used to separate cells

§  Cell is implanted into the uterus of a surrogate female parent where embryotic development continues

®    Problems with reproductive cloning

o   Increase in birth size and a variety of birth defects in vital organs such as heart, liver, and the brain

o   Premature aging and problems with the immune system

o   The relative age of the cloned cell’s chromosomes affect their health

§  The tips of the chromosomes called the telomeres shrink as you age

·       Eventually the telomeres can no longer divide, and the cell dies

·       This means cells taken from an adult can result in a short lifespan as half the telomeres are left

®    Therapeutic Cloning

o   Purpose is to produce stem cells for use in treatment of injury or disease

o   Involves the creation of an embryo from stomatic cells

o   These cells have the same identity as the patient and thus do not induce an immune response

®    Stem Cells

o   Stem cells are undifferentiatedcells

§  they are able to specialise into any type of cell

·       nerve cells, blood cells, liver cells, muscle cells, other stem cells

o   They are used for processes such as

§  Parkinson’s

§  Type 1 diabetes

§  Heart disease

§  Spinal injuries

o   The process of using stem cells is not typically reversible

o   Issues with using stem cells

§  Ethical issues around use of a live embryo

®    Genetic modification

o   Genetic information is changed by inserting a new gene

o   These are copied into daughter cells through mitosis

®    Genetics Review

o   Phosphates have a negative charge

o   Weak hydrogen bonds between the bases

§  2 H bonds between AT and

§  3…