horizontal gene transfer

vertical gene transfer

parent to offspring

horizontal gene transfer

passes genetic information between cells thru a process independent of cell division

hgt creates

genetic diversity in asexual microbes

plasmids

used by cells to share genetic information, aren’t required but can confer an advatange

conjugation

transfers genetic material between bacteria through direct contact

conjugation requires

a fertility plasmid that encodes a small hollow pilus that transfers plasmids

high frequency recombination (Hfr)

arise when fertility plasmid merges w/ bacterial cell’s chromosome, can pass on copied segments of DNA beyond usual set of genes found on fertility plasma

transformation

occurs when bacteria take up DNA from their environment. pilus is not involved

exogenous DNA passes cell wall during transformation

through an absorption process

competent cells

cells that can be transformed

transduction

introduction of new genetic material into a bacterial cell by a virus

bacteriophage

viruses that infect bacteria

possible outcomes of transduction

phage dna directs production of phage particles or phage dna integrates into host cell genome

generalized transduction

occurs when phage particles are built and a fragment of host DNA is packaged instead of phage DNA

specialized transduction

occurs when temperate phages integrate their DNA into host cell’s genome, the phage reactivates and leaves host cell, building new phage particles. the phage may take specific surrounding bacterial genes w/ it

transposons

genes that can jump to different locations on the genome

copy and paste strategy of moving transposons

copy is made and then pasted in new location

cut and paste strategy of moving transposons

DNA transposon is not copied before it is excised and moved

transposons contribute to genetic diversity

copy genes from plasmid and insert into genome, combine w/ plasmids to get transferred between cells