Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings PowerPoint Lectures for Biology, Seventh Edition Neil Campbell and Jane Reece Lectures by Chris Romero Chapter 14 and 15 DNA Technology and Genomics

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Overview: Understanding and Manipulating Genomes Sequencing of the human genome was largely completed by 2003 after a 13 year effort by 2 major teams. 2 main goals: sequence all 3 billion human base pairs and identify genes – found approximately 23,000 instead of the predicted 100,000. What organisms have been sequenced? Look here: _guide_p1a.shtml _guide_p1a.shtml

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Selective Breeding: Humans use organisms that express the traits they want, to reproduce and spread those genes: Ex: dog breeds, modern corn, meatier chickens

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Green Fluorescent Protein: GFP Found in a deep sea jellyfish. Today this gene is used to tag proteins to see development, cancer cells etc.

LE 20-3 How to insert genes into other organisms: Cut both genes with same restriction enzyme so they base pair together. Put new genes back into organism: Restriction enzyme cuts the sugar-phosphate backbones at each arrow. One possible combination DNA fragment from another source is added. Base pairing of sticky ends produces various combinations. DNA ligase seals the strands. Recombinant DNA molecule

LE 20-2 Bacterium Bacterial chromosome Plasmid Gene inserted into plasmid Cell containing gene of interest Gene of interest DNA of chromosome Recombinant DNA (plasmid) Plasmid put into bacterial cell Recombinant bacterium Host cell grown in culture to form a clone of cells containing the “cloned” gene of interest Protein expressed by gene of interest Protein harvested Gene of interest Copies of gene Basic research on gene Basic research on protein Basic research and various applications Gene for pest resistance inserted into plants Gene used to alter bacteria for cleaning up toxic waste Protein dissolves blood clots in heart attack therapy Human growth hor- mone treats stunted growth

LE 20-7 Primers New nucleo- tides PCR – polymerase chain reaction. Making millions of copies of a portion of DNA to test. Thanks to bacteria from Yellowstone (with a heat stable DNA polymerase) – the reason forensics has evolved, sequencing the mammoth, Neanderthal etc.. 3 parts –1) heat DNA slightly to separate, 2) cool so primers can bond 3) DNA polymerase adds nucleotides to 3” ends and makes numerous copies.

LE 20-8 Cathode Power source Anode Mixture of DNA molecules of differ- ent sizes Gel Glass plates Longer molecules Shorter molecules

LE 20-9 Normal  -globin allele 175 bp201 bpLarge fragment Sickle-cell mutant  -globin allele 376 bpLarge fragment Ddel Ddel restriction sites in normal and sickle-cell alleles of  -globin gene Normal allele Sickle-cell allele Large fragment 376 bp 201 bp 175 bp Electrophoresis of restriction fragments from normal and sickle-cell alleles RFLP – restriction length polymorphisms. Mutations that can be detected to see if you have disease causing alleles.

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Human Gene Therapy Gene therapy is the alteration of an afflicted individual’s genes – like sickle cell or cystic fibrosis. Gene therapy holds great potential for treating disorders traceable to a single defective gene Vectors are used for delivery of good genes into cells – like viruses which can easily fit receptors. Retroviruses make a DNA copy with the gene

LE Cloned gene Retrovirus capsid Bone marrow cell from patient Inject engineered cells into patient. Insert RNA version of normal allele into retrovirus. Viral RNA Let retrovirus infect bone marrow cells that have been removed from the patient and cultured. Viral DNA carrying the normal allele inserts into chromosome. Bone marrow

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Animal Husbandry and “Pharm” Animals Transgenic organisms are made by introducing genes from one species into the genome of another organism Transgenic animals may be created to exploit the attributes of new genes (such as genes for faster growth or larger muscles)

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Genetic Engineering in Plants Agricultural scientists have endowed a number of crop plants with genes for desirable traits Plants can produce a toxin from a bacteria, so when a caterpillar eats the leaf – its stomach explodes. Plants can also be “Round-up” resistant, so the weeds die from it but not the plants. Many plants world wide are now GMO’s – golden rice (w/ vitamin A for blindness) strawberries, tomatoes, corn etc…

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings Cloning – entire organism. A way to bring back or prevent extinctions? Take DNA from a host cell (skin, hair) suck out DNA from an egg and put new DNA in. Implant in a surrogate mother (must be related enough to not reject embryo). Wait until birth. Dolly and many mammals have been cloned. Problems with disease and aging ?? Genes not turning on as they do in infancy. Conclusion – clone in mammals not identical, not same personality

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings SNP – single nucleotide polymorphism Blonde hair is a mutation. One idea is that light- skin genes helped ancient humans survive in Northern Europe's low-light conditions, and light hair may have been a byproduct.