Horizontal Genetic Transfer

Explains much about how different modes of evolution can occur, through alternate paths by which genes can be acquired, and also explains why genetic engineering could have unforeseen (and even more importantly, unforeseeable) consequences:

Horizontal Gene Transfer: Bacteria Transmit Genetic Code without Sex

In the absence of sex, how are bacteria able to adapt so fast to changing conditions? Gene transfer

By David Biello September 30, 2010

Oceans are highly dynamic habitats: nutrients flood in from a river only to dwindle away over intervening days or weeks; currents shift the mix of waters; an oil spill suddenly makes hundreds of millions of liters of hydrocarbons available to eat. Without sex—and many bacteria don’t have sex thank you very much—it’s harder for marine microbes to mix it up and achieve the genetic diversity that’s key to population success. So how to adapt quickly rather than wait for the long, slow process of mutation in a species? The answer is so-called horizontal gene transfer (HGT)—which actually comprises a number of processes that enable bacteria to swap genetic code.

Marine biologist Lauren McDaniel of the University of South Florida and her colleagues tested the gene transfer abilities of nine alphaproteobacteria. These specific strains of bacteria have so-called gene transfer agents” (GTAs) or, as McDaniel calls them, “little genetic escape pods.” In essence, Rhodobacter capsulatus, Roseovarius nubinhibens ISM and Reugeria mobilis 45A6, among others, could create packets of genetic material and then eject them into the surrounding waters.

According to the findings, published October 1 in Science, these packets were then absorbed by their fellow bacteria and incorporated into their own genetic code. “These particles were able to transfer genes from a donor strain to wild-type bacterial strains as well as natural populations,” McDaniel explains.

Horizontal Genetic Transfer