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Unformatted text preview: Genetic Variation in Bacteria Contain only 1 copy of genome (haploid). Circular chromosome with numerous extra-chromosomal plasmids. Plasmids . Small, circular pieces of DNA, independent from main chromosome. Replication independent of main chromosome (have their own origin) Easy to grow; rapid growth rate (double every 20-25 minutes if conditions are favorable) Few genes (approx. 3000) compared to humans Bacterial Mating/Genetic Recombination A. Transformation : [ Uptake of extra cellular DNA, DNA incorporated into their genome. [ Source = DNA from other dead bacteria. Natural Transformation. DNA is bound to membrane and cut up with nucleases. Fragments enter cell and then incoming DNA replaces portion (regions of matching genes [ie. Homologous regions]) Requires about 12 separate genes. [ Unselective. [ Can be used in lab. Any source of DNA can be coaxed into E.coli through transformation. Artificially transformation used by cooling bacteria and treating with CaCl. Take up intact plasmids. Take up intact plasmids....
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