Genetic technology

Biotechnology Alteration of cells or molecules for specific application. Genetic engineering refers to any biotechnology that manipulates genetic material. Organisms that harbor DNA from other species are termed transgenic and their DNA is called recombinant DNA.

Patent law Patent law regarding DNA has evolved with the technology since 1970s, and is still changing.

Amplifying DNA The first known technology that amplified DNA were invented in 1970’s and 1980’s. the best is the polymerase chain reaction (PCR), invented by Kary Mullis 1983.

PCR PCR is based on the natural process of DNA replication. PCR uses DNA polymerase to rapidly replicate a specific DNA sequence millions of times (detectable levels).

RNA amplification Invention that copies target DNA into RNA and then uses RNA polymerase to amplify the RNA.

Recombinant DNA Recombinant DNA technology adds genes from one type of organism to the genome of another. Recombinant DNA is called gene cloning.

Constructing recombinant DNA Restriction enzymes: cut donor and recipient DNA at the same sequence. Cloning vectors: DNA to carry the donnor DNA. Recipient cells.

Restriction enzymes Bacteria have hundreds of types of restriction enzymes. Some cut particular sequences of 4,5 or 6 bases that are symmetrical in a specific way, from the 5’ to 3’ direction, on both strands of the DNA. Ecor1 cuts at the sequence GAATTC. The complementary sequence is CTTAAG.

Palindrome This type of symmetry is called Palindrome. A sequence of letters that reads the same in both directions. Cutting double stranded DNA creates single- stranded extensions called (sticky ends).

Cloning vectors carry DNA from cells of one species into cells of another. Plasmid : is commonly used. It is a circle DNA occurs naturally in bacteria, yeasts and plant cells. Viruses that infect bacteria, called bacteriophages are another type of vector. Disabled retroviruses as bacterial or yeast artificial chromosomes (BAC or YAC).

Cloning vectors Size of insert accepted (kb) vector Up to 15Plasmid Up to 90Bacteriophage BAC YAC

Genomic library A collection of of DNA pieces representing the genome of an individual, including introns.

cDNA library Complementary DNA library is made from the mRNAs in a differentiated cell, which represent the proteins manufactured there. cDNA represents only protein-coding genes.

How to select recombinant DNA 3 types of cells: 1)Cells lack plasmids. 2)Cells contain plasmids that do not contain a foreign gene. 3)Cells that contain plasmids with the foreign gene (the goal).

Two strategies Antibiotic resistance gene Color change reaction.

Products from recombinant DNA Mass production of protein-based drugs. They are pure and human version. Insulin is the first drug produced by recombinant DNA. Interferons treat hepatitis C and B, Kaposi sarcoma, and multiple sclerosis. Factor VIII for blood clotting in hemophilia.

Cost problem $20000 annually for multiple sclerosis treated by interferon-beta. Tissue plasminogen activator (tPA) costs $2200 for one shot when heart attack if injected within 4 hours.

Retinoblastoma is inherited? Loss of heterozygousity Mechanisms to uncover the mutant allele: 1)Chromosome loss 2)Mitotic recombination 3)Deletion 4)Inactivating nucleotide subtitutions

Acute leukemia Some result from a chromosomal translocation that fuses a transcription factor with a leukocyte regulatory sequence. Other result from a chromosomal translocation that fuses two genes to create a novel chimeric gene.