What are In Vitro Fertilization and Embryo Screening? In Vitro Fertilization (IVF) – Sperm and egg united in a petri dish, followed by implantation of embryo(s) into mother’s uterus; pioneered by Robert Edwards as a treatment for infertility (Nobel Prize, 2010); roughly 20-30% success rate with a single embryo – First “test-tube baby” (Louise Brown) born 25 July, 1978; more than 4 million babies born via IVF; controversies include multiple births (ex. octuplets) and un-used embryos Embryo Screening –Cells from embryo harvested in lab (vs. amniocentesis with a fetus), and subjected to karyotyping and DNA fingerprinting –Pre-implantation genetic diagnosis (PGD): testing for genetic conditions before an embryo is chosen to be used; allows bone-marrow match for other sibling (e.g. My Sister’s Keeper)

Fig. 7.19a

How are Clones Produced?

Cloning Techniques –Enucleated egg cell implanted with donor nucleus (frogs and mice) or fused with 8-cell blastocyst (lamb, cow, pig, and monkey) Success rate is typically low, but improving (ex. Gaur, early 2001: 44 embryos in 32 surrogate cows led to eight pregnancies, only one successful) Questions over health of clones: lung problems; early aging suspected Success rate using adult donor cells varies by cell type (“Dolly” was from mammary gland cells) Success rate increased by incubation of donor nucleii in oocyte cytoplasm

What Are the Potential Applications of Cloning? Therapeutic Cloning –Affected individual (ex. paralysis) cloned, resulting embryo used as a source of embryonic stem cells (overcomes rejection problem common with organ donations) Cloning Organisms (Reproductive Cloning) –Conservation of endangered species (to increase population from critically low population) Resurrection of extinct species (?) –Cloning deceased pets –Increased efficiency of biotechnology Transgenic animals can be cloned Production of genetically engineered organs that reduce rejections –Human reproduction when other techniques have failed (child would be genetically related to only one parent)

Mammals Cloned

What are Stem Cells? Embryonic and Adult Stem Cells –Embryonic: totipotent, can be cultured  stem line; can be obtained from fertility clinics (un-used embryos), or from umbilical tissue (companies store cord blood) –Adult: success varies by cell type; typically not totipotent, and potency may not last; not easily cultured, but tech- niques improving (cells re-programmed to embryonic state) Potential Uses of Stem Cells –Possible treatments of diseases involving dead or damaged cells (spinal damage, Alzheimer’s, and Parkinson’s); success in several cases with mice; concerns regarding possibility of implanted cells becoming cancerous –From in U.S., publicly funded research allowed only on existing stem-cell lines (some leading specialists relocated to places like Singapore); recent changes under Obama Administration challenged in the courts