Environmental Genomics
Genes and ecosystem services
Finding the gene for recycling
Dead and decomposing organisms provide a crucial ecosystem service: recycling nutrients. Bacteria control these cycles but before the advent of genomics it was difficult to investigate the genes responsible for such activities because scientists could rarely culture the bacteria in the laboratory.
Environmental genomics scientists can now examine millions of genes from
uncultured, unknown soil bacteria. By sequencing these genes, they found
many new species of bacteria and it is now possible to examine how a particular
species contributes to the recycling process.
The gene libraries have been immortalised in freezers so that they can be used by scientists to look for other genes in the future.
Nitrogen fixing and the Coca-Cola hypothesis
Intriguingly, scientists could not identify the genes involved in 'fixing' biological nitrogen - a process in which bacteria convert nitrogen gas into a form which can be used by plants.
It seems that the bacteria containing the genes for this process are much rarer in the soil than was previously thought - an idea summarised in what is called the 'Coca-Cola hypothesis': Only a tiny proportion of the working population is directly involved in manufacturing soft drinks, but those that do, can do so very efficiently. As a result, the beverage is present in cafes, bars and shops from Malta to Mongolia. Similarly, only very few cells, perhaps one in a thousand, in the bacterial population may fix nitrogen, but these specialists are also highly efficient at their jobs ensuring ecosystem and global distributions.
The hunt continues for these specific genes.