Final Exam: Lateral (Horizontal) Gene Transfer
Terms in this set (16)
horizontal gene transfer
The transfer of genes from one genome to another through mechanisms such as transformation, conjugation, or transduction.
vertical gene transfer
Genes acquired during reproduction
an experiment carried out by Griffith using the heat-killed bacteria in mice to discover that a factor in heat-killed, disease-causing bacteria can "transform" harmless bacteria into ones that can cause disease
In bacteria, the direct transfer of DNA between two cells that are temporarily joined by a pilus.
created by F+ cell; the cell transfer its F plasmid to F-
ability to form pili for conjugation and associated functions required for the transfer of DNA from donor to recipient. It may exist as F- plasmid or be integrated into the bacterial chromosome.
possess F factor integrated into the bacterial genome.
possess F factor as a plasmid independent of the bacterial genome. The F plasmid contains only F factor DNA and no DNA from the bacterial genome.
do not contain F factor. Will act as the recipient.
is formed by incorrect excision from the chromosome, resulting in an F plasmid carrying bacterial sequences that were next to where the F episome was inserted.
The process in which infection by a virus results in DNA being transferred from one bacterium to another
Lytic phage infects bacterium, leading to cleavage of bacterial DNA and synthesis of viral proteins. Parts of bacterial chromosomal DNA may become packaged in viral capsid. Phage infects another bacterium, transferring these genes.
Lysogenic phage infects bacterium; viral DNA incorporated into bacterial chromosome. When phage DNA is excised, flanking bacterial genes may be excised w/ it. DNA is packaged into phage viral capsid and can infect another bacterium.
- have two pathways
seven functions of plasmid
1. conjugative- genes for pilus formation and plasmid transfer
2. resistance - toxin and antibiotic resistant
3. bacteriocin - makes toxins that destroy other cells
4. virulence- make them pathogenic, resist to host defense mechanism
5. symbiosis - inection of legumes for N2 fixation to NH4
6. Cataboic - degrades hazardous chemicals
importance of plasmid
1. environmental adaptation: genetic flexivility to cell with less cost
2. selective pressure and evolution: plasmid rapidly spread to many species to allow survival
Why is LGT important?
Without reproducing, it allows recombination and gene shuffling for the cell.