Genetic Technology Section 11.1

What is Biotechnology? Biotechnology is using living organisms to produce something useful for humans Selective breeding – breeding organisms to produce desirable traits Inbreeding – crossing of organisms that have similar genotypes so the desirable traits will eventually be homozygous (crops, horses, dogs... not people!) Can also increase the chance of harmful recessive traits showing up

Consider Dalmatians... A white coat with crisp spots is the desired look breeders want However, the presence of white in the hair coat increases the likelihood of deafness Breeders were selecting for the perfect coat color, but at the same time they were also selecting the gene for congenital deafness! 8% of all Dalmatians in the US are bilaterally deaf and 22% are unilaterally deaf

Hybridization Outbreeding – crossing distantly related organisms Combines desirable traits from different parents Hybrid vigor – larger, healthier offspring may be produced, but often sterile if different species. Mule from male donkey and female horse is more docile than donkey but hardier than a horse

Genetic Engineering Genetic engineering – manipulating genes for practical purposes. Can yield changes in a very short period of time

Cohen and Boyer (1973) Stanley Cohen and Herbert Boyer They isolated the gene that codes for rRNA from the DNA of an African clawed frog. They inserted the gene into E. coli bacteria. During transcription, the bacteria produced frog rRNA!

Changing Genomes Recombinant DNA – formed when DNA is combined from different organisms Human genes that produce human proteins can be added to bacteria or yeast to mass produce the proteins Mechanism of Recombination, 3D animation with with basic narration Mechanism of Recombination, 3D animation with with basic narration Genetic Engineering to Procuce Insulin

Changing Genomes Vector – carrier of the DNA Plasmid – small circular pieces of DNA found in bacteria Genes are spliced into the genome of the vector by utilizing restriction enzymes and sticky ends Restriction Enzymes – recognize specific DNA sequences and cut the DNA between specific nucleotides Sticky Ends – pieces of DNA with short single stands on each end that are complimentary to each other

MakingINSULIN Human DNA Restriction enzymes cut the DNA DNA Fragments with “Sticky Ends”

Small, Circular, Bacterial DNA = Plasmid Restriction enzyme cuts the plasmid Insulin gene inserted into plasmid rDNA used as vector

Eaten Cheddar Cheese Lately? One of the most successful applications of recombinant DNA technology for foods is the production of chymosin, an enzyme used in cheese making. Chymosin, when added to milk, causes the curd to form. Chymosin, which was available only from the stomach of calves, was in limited supply due to a reduction in the veal industry and expansion of the cheese industry. Then the gene for chymosin production was incorporated into the DNA of both bacteria and yeasts. Pure chymosin can now be made. The enzyme is identical to that produced in the calf and the process itself adds no contaminants. The FDA evaluated the safety of the process and the product itself in 1990 and ruled that the enzyme preparation was safe for human consumption. Most Americans who have had a slice of Cheddar cheese since 1990 have eaten a product improved by biotechnology.