Genetic Technology

Applied Genetics Selective breeding - produces organisms with desired traits. 1. Takes time, patience and several generations. 2. Increases the frequency of desired alleles.

Inbreeding – develops pure lines. 1. Mating closely related individuals. 2. Results in offspring that are homozygous for most traits. 3. Inbreeding can bring out harmful, recessive traits because there is a greater chance that two closely related individuals both may carry a harmful recessive allele for the trait. Click inside box to play movie

Hybrids Hybridization – crossing parents with different forms of a trait. a. Plants produced from crossing two cultivars often bigger and better. b. Animals – when two species are crossed sterile hybrids are produced. Zorse – cross between a horse and a zebra.

Determining Genotype A test cross is done to determine the genotype of an unknown dominant individual. 1. A dominant phenotype can be homozygous or heterozygous. 2. Cross the unknown to a homozygous recessive. If any of the offspring are recessive, you know the unknown is heterozygous. Unknown Homozygous recessive dd Unknown is DD Unknown is Dd

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Recombinant DNA Technology Genetic engineering – a faster and more reliable method for increasing the frequency of a specific allele in a population. Recombinant DNA – made by connecting or recombining fragments of DNA from different sources.

Transgenic Organisms Organisms that contain foreign DNA. Achieved by a three step process: 1. Restriction enzymes cut, or cleave the DNA. A. If the same enzyme is used to cleave DNA in two different organisms, the DNA pieces will tend to stick together. B.“Sticky ends” are key to recombinant DNA. Click inside box to play movie

C. Gel electrophoresis is used to separate the DNA pieces cut with restriction enzymes. The Electrical Field Filling the wells Fragments move

Vectors transfer DNA to a host cell. A. Biological = viruses and plasmids. B. Mechanical = micropipettes and gene guns. Click in box to play movie

DNA is rejoined by gene splicing. A. Transferred to the host by one of the vectors. B. Duplicates as the host cell divides.

Polymerase Chain Reaction (PCR) Method of replicating DNA outside of living organisms. Essential for analysis of DNA. Has allowed molecular genetics to become part of criminal investigations. Click in box to play movie

Applications of DNA Technology Cloning of organisms, as well as genes. Pure DNA for study of specific genes from PCR. Recombinant bacteria. a. industrial use – break down pollutants. b. medical use – produce hormones, insulin or. amino acids. c. used in agriculture to prevent frost on crops. Transgenic animals – scientists can create animals with human diseases and animals that can produce human materials.

Transgenic plants – have been engineered to resist herbicides, produce internal pesticides and increase their protein production. Click in box to play movie

Human Genome The Human Genome Project – has mapped and sequenced all human genes. A. We have a linkage map. 1. 35 - 40,000 genes on 46 chromosomes. 2. We know where the genes are located, but do not know the function of all genes.

Applications of the Human Genome Project Diagnosis of genetic disorders followed by gene therapy. A. Insertion of normal genes into human cells to correct genetic disorders. B. fetal diagnosis and therapy.

A. Criminal investigations. DNA Fingerprinting – no two individuals have the same DNA fingerprint, except identical twins. A. Criminal investigations. B. Identification of family members, dead or alive.