Dna Cloning

DNA Cloning
* Nucleotides: A sugar, a nitrogen base, and a phosphorus group.
* Cloning: a set of laboratory methods that uses living cells to make copies of specific DNA fragments.
*DNA cloning: processes used to create copies of DNA fragments.
Some types of bacteria resist infection by bacteriophage (T4), which are viruses that inject their DNA into bacterial cells. Specialenzymes inside the bacteria chop up any injected bacteriophage DNA before it integrates into the bacterial chromosome. These are called restriction enzymes, which will cut DNA wherever a specificnucleotide sequence occurs (example EcoRI). Many restriction enzymes leave single-stranded tails (“sticky ends”) that base-pair together, regardless of the origin of the DNA.
DNA ligase enzyme speeds theformation of covalent bonds between matching sticky ends in DNA fragments. Using the appropriate DNA ligase and restriction enzymes help researchers cut and paste DNA from different organisms resultingin recombinant DNA (hybrid molecule composed of DNA from two or more organisms).
Steps
1. Making recombinant DNA.
2. Insertion of specific DNA fragments into plasmids (small circles ofbacterial DNA that are independent of the chromosome) or another cloning vector (molecule that carries foreign DNA into host cells).
3. So, that when the bacterium divides, it copies its chromosomeand any plasmid which gets copied and distributed to descendant cells. Each clone contains a copy of the vector and the foreign DNA it carries.
Researchers who study eukaryotic genes work with mRNAbecause introns (segments or sequences of the base) have already been snipped out. mRNA can’t be cloned directly because enzymes only cut and paste double-stranded DNA. However, reverse transcriptase(replication enzyme of certain types of viruses) transcribes mRNA into DNA. This enzyme uses the mRNA as a template to assemble a strand of complementary DNA or cDNA (cloned DNA). The DNA added...