A slew of press reports have trumpeted the finding of a new strain of bacteria recovered from Lake Vostok. Vostok is located in Antarctica, where the liquid water is buried under several kilometers of ice that have kept it isolated from the outside environment for millions of years. After several years of efforts and a pause to work out decontamination procedures, a Russian team drilled down to the lake water for the first time last year.
The hope was that, like several other under-ice ecosystems (most notably the one that creates Blood Falls), Vostok would host a community of bacteria that scrapes out a living through some combination of residual organic material and energy provided by geological processes. According to the press accounts, that hope seems to have been borne out.
But what sort of life are we looking at? Almost all of the accounts trace back to a RIA Novosti account that has very little in the way of details. The Russian researchers have apparently sequenced some DNA from the organism; although they don't specify which DNA, chances are good that it's the gene for ribosomal RNA, which is very useful for placing the organism within the tree of life. The differences with known species of bacteria indicate that it's clearly a new species, and the initial analysis suggests that it doesn't even group neatly with any of the major categories of bacterial life we're aware of.
But claiming it's a whole new branch off the tree of life should probably require more extensive sequencing of other areas of the genome. More data could probably tell us something about how it ekes out a living in a frigid, isolated ecosystem, and help figure out what its closest relatives are.
To be clear, it almost certainly has some relatives. One of the scientists is quoted as saying, “If it were found on Mars, people would call it Martian DNA. But this is DNA from Earth."
As noted in the article, however, the match between its DNA and known species on Earth reached at least 85 percent in some stretches, clearly showing its kinship to this planet's other biological inhabitants. And Vostok has only been separated from the rest of that life for fewer than 30 million years. That's a long time by almost any standard, but less than one percent of the time that bacterial life has been evolving on Earth.