c13- genetic technology pp. 336 - 365. contents 13.1 applied genetics 13.2 recombinant dna...
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Applied GeneticsApplied Genetics
• Selective Breeding- choosing organisms with the most desired traits to serve as parents of the next generation.
Applied GeneticsApplied Genetics
• Inbreeding- mating closely related individuals; results in homozygous offspring
• Animal breed• Plant cultivar
Applied GeneticsApplied Genetics
• Hybrids increase productivity and disease resistance in crops
• Usually larger and stronger than purebred parents
Hybrid sorghum
Determining GenotypesDetermining Genotypes
• Test Crosses- unknown genotype X known genotype
• Offspring ratios indicate genotype of unknown parent
• Homozygous dominant if 100% heterozygote
• Heterozygous if 1:1 ratio• P. 340
13.2 Recombinant DNA Technology13.2 Recombinant DNA Technology
• Genetic Engineering faster & more reliable method to increase the frequency of allele
• Involves cutting DNA from one organism & inserting it in another
• Recombinant DNA Technology
Recombinant DNA TechnologyRecombinant DNA Technology
• Transgenic organism has foreign DNA
• Tobacco plant with firefly DNA
Recombinant DNA TechnologyRecombinant DNA Technology
• Step 1- isolate foreign DNA fragment to be inserted• Step 2- attach DNA fragment to a carrier• Step 3- transfer into host organism
Restriction Enzyme Cleaves DNARestriction Enzyme Cleaves DNA
• • Restriction enzymes bacterial proteins with ability to cut DNA sequence at specific nucleotide sequence
• Palindromes-same sequence in opposite orders
• Hundreds of restriction enzymes
• Fragments have sticky ends
Vectors Transfer DNAVectors Transfer DNA
• Carrier that transports foreign DNA into host
• Here a retrovirus serves as vector for engineered bone cells.
• Can be biological or mechanical
• Bacterial plasmid is a small ring of DNA
• Micropipette or DNA coated bullet from a gene gun
• ML 13.1, p. 343
Gene CloningGene Cloning
• Clones are genetically identical copies
• Each identical recombinant DNA molecule is called a gene clone.
• Recombinant DNA can be inserted in yeast, plant cells and animal cells.
Animal CloningAnimal Cloning
• Dolly the sheep first cloned animal, 1997
• Dewey, first cloned deer, 2003
Polymerase Chain ReactionPolymerase Chain Reaction
• PCR method to replicate DNA outside an organism
• Thermocycler uses heat to separate DNA strands
• Enzyme used to repeatedly replicate DNA
• Used in crime investigations and diagnosis of infectious disease
Sequencing DNASequencing DNA
• Sequencing DNA allows scientists to identify mutations
• Four tubes A, C, T & G tagged with different colors
• Strands separated by size using gel electrophoresis
Applications of DNA TechnologyApplications of DNA Technology
• Industrial• Produce chemical
compounds– Indigo for dye– Cheese production– Laundry detergent– Pulp & paper products– Sewage treatment
Applications of DNA TechnologyApplications of DNA Technology
• Medical • Production of proteins
– Human growth hormone– Insulin– Antibodies– Enzymes
Applications of DNA TechnologyApplications of DNA Technology
• Agriculture• Crop development• Insect resistance• Genetically modified
crops• Vitamin fortified food• Allergy reduction
13.3 The Human Genome13.3 The Human Genome
• In 2003 scientists in the Human Genome Project obtained the DNA sequence of 3 billion base pairs making up the human genome.
• It is nearly the same (99.9%) in all people.
13.3 The Human Genome13.3 The Human Genome
• Only about 2% of the human genome contains genes which are the instructions for making proteins.
• Humans have about 30,000 genes; the functions of more than half of them are unknown.
13.3 The Human Genome13.3 The Human Genome
• Almost half of human proteins share similarities with other organisms, underscoring the unity of life.
• Much is still unknown!
The Human GenomeThe Human Genome
• Genetic map that gives the relative location of genes on a chromosome is called a linkage map.
• Crossover occurs during prophase I of meiosis.
• Genes that crossover frequently must be farther apart.
The Human GenomeThe Human Genome
• Biotechnology increases the efficiency of mapping with new methods such as polymerase chain reaction (PCR) to make millions of copies of DNA fragments
The Human GenomeThe Human Genome
• Sequencing the human genome:
• 1) cleaving DNA into fragments
• 2) cloning fragments• 3) sequences aligned• All automated
ApplicationsApplications
• Diagnosis of genetic disorders
• Can be diagnosed before birth using amniotic fluid
• Isolating DNA• Using PCR to analyze
ApplicationsApplications
• Gene Therapy• Insertion of normal
genes into human cells to correct genetic disorders
• SCID, cystic fibrosis, sickle cell anemia, hemophilia