Lateral Gene Transfer
Source: Andersson & Hughes, 2010
Normal gene inheritance happens through recombination of genes into the next generation of organisms. Another way in which non-inherited genes enters an organism’s genome is through horizontal gene transfer, or lateral gene transfer. This is defined as the transfer of genetic material without reproduction and cell division (Boto, 2009). Horizontal gene transfer has been an important force in the evolutionary history in both prokaryotes and eukaryotes (Boto, 2009). This type of transfer is very common in bacteria and can lead to resistance to antibiotics (Barlow, 2009).
Methods of Transfer[]
There are three ways that horizontal gene transfer can occur which includes transformation, transduction and conjugation (see image). Transformation occurs when short pieces of naked DNA are taken into the cell from the environment (Ochman, Lawrence & Groisman, 2000). There is potential with this type of transfer for these fragments to reach to species that are not closely related (Ochman, Lawrence & Groisman, 2000). Trasduction is the transfer of DNA through a bacteriophage, which are present within the environment. Cells that accept bacteriophages require them to have specific receptors that make transfers possible (Ochman, Lawrence & Groisman, 2000). Conjugation includes transferring genetic material through physical contact, unlike both transduction and transformation which do not require cells to be in close proximity of each other (Ochman, Lawrence & Groisman, 2000).
Relavance []
Horizontal gene transfer is a very common occurrence in bacteria, and can lead to resistance in many bacteria to antibiotics (Ochman, Lawrence & Groisman, 2000). This can be of great concern as this could undermine medical abilities to treat diseases, especially as resistance can continue even when the use of antibiotics stops (Barlow, 2009). Horizontal gene transfer is also important because this mechanism can be used to transfer DNA from one type of bacteria to similar but differnt species of bacteria (Serafini & Matthews, 2009).
References:
Andersson, D. I., & Hughes, D. (2010). Antibiotic resistance and its cost: is it possible to reverse resistance?. Nature Reviews Microbiology, 8(4), 260-271. doi:10.1038/nrmicro2319
Barlow, M. 2009. What antimicrobial resistance has taught us about horizontal gene transfer. Methods of Microbiology, 532, 397-411.
Boto, L. 2009. Horizontal gene transfer in evolution: facts and challenges. Proceedings of the Royal Society, 277(1683), 819-827.
Ochman, H., Lawrence, J. G. & Groisman, E. A. 2000. Lateral gene transfer and the nature of bacterial innovation. Nature, 405, 300-304.
Serafini, A. & Matthews, M. (2009). Microbial resistance to triclosan: a case study in natural selection. The American Biology Teacher, 71(9). Retrieved from http://www.nabt.org/websites/institution/File/pdfs/american_biology_teacher/2009/November/ABTNov09Serafini536-40.pdf