Download Inter-domain lateral gene transfer

Mor Lurie-Weinberger
Inter-domain lateral gene transfer - the case of methanogenic archaea
Abstract:
Atmospheric methane (CH4) is a potent green house gas, with global
warming potential 21 times that of CO2. Methane emissions from agriculture
represent around 40% of the emissions produced by human activities,
thetechnologies to reduce these emissions are lacking. Additionally, cattle
typically lose 6 % of ingested energy as methane, so inhibiting methanogenic
metabolism in cattle is highly desirable in agriculture.
Ruminant methane is formed by the action of methanogenic archaea typified
by Methanobrevibacter ruminantium, and Methanobrevibacter smithii, two
wide-spread mammal-associated microorganisms. M. smithii is also the most
abundant methanogen in the human, with a genome which is “tailored” to the
intestinal environment. Since the mammalian intestine is a niche
predominantly colonized by a multitude of bacterial species, it's likely that the
genomes of methanogenic Archaea in the intestines have acquired their
ability to prosper in this environment through inter-domain lateral gene
transfer (LGT) from bacterial species that dominate this niche.
An automatic phylogenetic pipeline was utilized to identify LGT genes in M.
smithii. 298 LGT candidates were found, representing 18% of the genome.
The majority of these genes (88%) appear to be the result of LGT from
Bacteria into Archaea. These genes represent promising targets for
intervention, as their loss is expected to have an adverse effect on these
microorganisms' survival in ruminants. While many archaeal genes are similar
to those of eukaryotes, and therefore problematic targets for manipulation,
genes derived from LGT from bacteria are absent from eukaryotes, and are
thereby safer targets for manipulation, and might be used to reduce humaninduced global warming.