Genetic Piracy: Stealing Adaptations to Survive and Thrive

Hot Spring

Hot springs. West Thumb Geyser Basin Wyoming.
Photo credit: carolynconner

Picasso reportedly once said “Good artists borrow, great artists steal”, and, as one look at Apple Inc’s profits will tell you, he wasn’t far wrong. Believe it or not, this philosophy can also apply to evolution.

Galdieria sulphuraria is a species of red algae that inhabits environments which are incredibly hostile, even by non-anthropocentric standards. They make their home in a habitat that is salty, hot, highly acidic and enriched with toxic metals such as arsenic: Snooki’s swimsui…I mean a hot spring. Such extreme conditions are generally regarded as the exclusive domain of extremophile bacteria and archaea, but G. sulphuraria  thrives here and it can do so because it “stole” the necessary adaptations from such groups.

A recent study by Oklahoma State University revealed that at least 5% of G. sulphuraria‘s genome was acquired from bacteria or archaea. Scour the swag that these gene-pirates have commandeered and you’ll find genes that code for proteins which perform vital tasks such as heavy-metal detoxification. These proteins are essential for life in the harsh conditions present in hot springs, but exactly how G. sulpuraria managed to acquire them is unknown. Bacteria and archaea can exchange genetic material readily via a process known as horizontal gene transfer, but G. sulpuraria is a eukaryote and, as such, does not possess this ability.

Horizontal Gene Transfer via Plasmids

Horizontal Gene Transfer via Plasmids. Credit: Wikipedia Commons.

You may be familiar with horizontal gene transfer from articles or news reports on drug-resistant bacteria. Here, problems arise when individual bacteria with a genetic resistance to a particular drug share this resistance with others (even unrelated species). Take a hypothetical bacterial infection which can be treated with penicillin. Of the entire population that resides in the patient, perhaps 1% are resistant to the drug. Following treatment with penicillin, the susceptible bacteria perish and the drug resistant strain gains a higher prevalence relative to the entire population. It can transfer genetic material to non-resistant individuals via plasmids, conferring them with the same resistance. Eventually, all that will be left is the drug resistant strain. This resistance can then be transferred to other populations/species and likewise, it can receive any drug resistant genes that these other species may have. These genetic “swap-meets” are the driving force behind the emergence of so-called “super bugs”; bacteria which have become immune to a whole suite of drugs, making the diseases associated with them more difficult to treat over time.

HGT has been documented in more complex organisms, but the method of transfer is unclear. Parasites may be a viable candidate. A species-jumping parasite may bring genetic material from one host to another, but for now this is just a “best guess”. If we ever confirm that this is indeed a viable method of inter-species gene transfer one thing is certain: the number of morons trying to turn themselves into Spider-man with spider-parasites is going to go through the roof. Comic-Con is going to start looking like a monumental genetic-experiment gone wrong…

HGT gone wrong

Too late.
Photo credit: Jason Persse.

Source: Schönknecht, Gerald, et al. “Gene Transfer from Bacteria and Archaea Facilitated Evolution of an Extremophilic Eukaryote.” Science 339.6124 (2013): 1207-1210.

Images: Credits as per captions

carollynconner’s Flickr stream

Jason Persse’s Flickr stream

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