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Cloning Genetically identical molecules, cells, or organisms all derived from a single ancestor Plants are easily cloned – most adult plant cells are totipotent Animals: adult cells are multipotent – two cloning methods: –Embryonic splitting and nuclear transfer

Plants.. Easily cloned Formally cloned in 1950s, by Charles Steward –Cloned carrots by taking a chunk of cells and growing them in medium –Then transferred to soil. Each carrot is genetically identical to parent carrot –Uses plant hormones

Animals Not as easily cloned as plants Several methods exist for animal cloning Methods: –Embryo splitting- twins! – and nuclear transfer

Recombinant DNA DNA that has been altered by the recombination of genes from a different organism, typically from a different species Transgenic organisms –plant or animal that expresses DNA derived from another species Genetically modified organisms –An organism produced through genetic engineering

Transformation –Method of acquiring new genes, whereby DNA from one bacterium becomes incorporated into the DNA of another, living, bacteria Plasmids –Small, circular piece of DNA in the cytoplasm of many bacteria –Does not carry genes necessary for function, but can assist bacterial survival in certain circumstances, such as a gene for antibiotic resistance

Restriction enzymes utilized Bacterial enzymes that cleave DNA at specific sites Each type of restriction enzyme (from different bacteria) has own recognition and cutting sites When they cut DNA strand, they create “sticky ends”

Diagram

Prenatal Testing Genetic tests run on babies before they are born 2 types- Amniocentesis and Chorionic Villi Sampling (CVS)

Who should get their babies tested? Advanced maternal age (35+) Now they’re saying advanced paternal age too! Previous child with chromosomal aberration Parent with chromosome rearrangement X-linked disorder

Fetal Cell Sources

CVS: Chorionic Villi Sampling

Amnio… can be conducted weeks of pregnancy, and is considered safer CVS.. Can be conducted weeks, and has a slightly greater chance of problems

Possible Risks? Small risk of bacterial infection Even smaller risk of spontaneous miscarriage For these reasons, only high risk cases are tested

Cancer is A Failure of Genetic Control Characteristics of Cancer Cells: -Form tumors because the cells lack contact inhibition = -Cells lack specialization & become immortal do not contribute to normal functioning go through cell cycle repeatedly (this is abnormal) due to telomerase

Telomerase Enzyme that adds DNA to ends of chromosomes. If telomeres (ends of chromosomes) get too short, cells die by APOPTOSIS (programmed cell suicide) This enzyme keeps telomeres long – if they are too long the cells NEVER die – CANCER!

-Have abnormal nuclei due to a mutation damaged DNA -Spread to new locations produce enzymes to invade underlying tissue Cancer cells can travel through the bloodstream and the lymph and develop into secondary tumors. We say it metastasized

Cells are called cancerous when they invade surrounding tissues. The tumor is deemed noncancerous or benign if it stays as a single mass. When cells of a tumor have the ability to spread away from the original site through vessels we call it malignant

Development of cancer begins with a single abnormal cell & requires several mutations. Mutations occur in 2 types of genes –1. proto-oncogenes=genes that encode for proteins that promote cell cycle & prevent apoptosis – these help cells divide –They are OVEREXPRESSED during cancer

2.Tumor-suppressor genes=encode for proteins that inhibit the cell cycle & promote apoptosis These are UNDEREXPRESSED during cancer Most well known tumor suppressor gene - –A gene called p53 normally prevents cell division if there is damage to the DNA. If p53 mutates, the cells may continue to divide indefinitely. –About 1/2 of all human cancers have a mutation in this gene.

Activity of p53 Tumor Suppressor