Abstract
Plasmids serve as important tools in genetics and biotechnology labs, where they are commonly used make many copies of a particular gene. The aim of this experiment was to identify three mystery plasmids based upon their characteristics; such as size, antibiotic resistance, lacZ profile and conjugative properties. The results obtained showed that plasmid number2 was the pDSK519 plasmid and its size was 26229.58 Bp. Plasmid pDSK519 also was found to be resistant to kanamycin only and it possessed the LacZ gene. pDSK519 had the oriT gene but it did not have the tra gene. Plasmid number 22 was found to be pHSG298 as it had a size of 9767.08 Bp and it was found to be resistant to kanamycin only. It also possessed the LacZ gene and conjugation results showed that it did not possess the oriT gene the tra gene. Plasmid number 12 was found to be pRP1:: Tn501 as it was resistance to all three antibiotics. It was also found out that this plasmid did not possess the LacZ gene as evidenced by the white colonies. pRP1:: Tn501 had oriT gene as well as the tra gene as shown in the conjugation results. The use of plasmids in very beneficial towards humans and these types of experiments contribute greatly towards this.
Introduction
A plasmid is an extra-chromosomal DNA molecule separate from the chromosomal DNA which is capable of replicating independently of the chromosomal DNA (Chandrasegaran, 2008). In many cases, it is circular and double-stranded. Plasmids usually occur naturally in bacteria, but are sometimes found in eukaryotic organisms. Plasmid size varies from 1 to over 200 kilo base pairs (Russell and Sambrook, 2001). Plasmids can be considered to be independent life-forms that tend to form symbiotic relationships with their hosts, as they endow their hosts with useful packages of DNA to assist mutual survival in times of severe stress. For example, plasmids can convey antibiotic resistance to host bacteria, who may then