BIOL 142 Lecture Notes - Lecture 12: Chromosome, Rolling Circle Replication, Wild Type
Biology 142- Lecture 12- Horizontal Gene Transfer
Review of Complementation
• Complementation occurs when parents have mutations in different gene
• Non-complementation occurs when parents have mutations in the same gene
• You can determine how many genes contribute to a trait using complementation
Horizontal Gene Transfer
• Horizontal Gene Transfer is the transfer of genetic material or traits within the same
generation (also called a lateral gene transfer)
• Prokaryotes participate in this type of gene transfer because they are able to easily pick
up genetic material/information from the environment and other organisms
o They have an exposed genome due to the lack of a nucleus
o They are unicellular, so it’s easier to invade the entire organism
• Changing the fitness of a colony of organisms in an environment, only requires one
individual to adapt or change and the use of horizontal gene transfers
o One organism can pass on adapted DNA to an entire colony via horizontal gene
transfers
Modes of Horizontal Transfer: Transformation, Transduction, and Conjugation
• Transformation: this occurs when naked DNA from the environment invades another
organism’s cell and incorporates into the genome of the host cell and is expressed
o Griffith’s Experiment: an early observation of transformation: mice were treated
with different strains of bacteria, and it was recorded whether they lived or died
