How did Life on Earth arise? Are our kind, from the most simple virus to our primate kin, unique? It is possible that this warm, wet planet is a petri dish for an alien experimenter? It's possible that a meteor or comet came bearing the stuff of Life to our home. It is just as possible that anywhere in the Universe, if water or liquid methane stirs up the dirt, Life will happen… and it will be along a design not too different from our own. Physics and chemistry may be all that is required. We do got rules around here.
This is an excerpt from the Wikipedia entry on Panspermia (Greek for "Seeds Everywhere").
On May 11, 2001, two researchers from the University of Naples claimed to have found live extraterrestrial bacteria inside a meteorite. Geologist Bruno D'Argenio and molecular biologist Giuseppe Geraci claim the bacteria were wedged inside the crystal structure of minerals, but were resurrected when a sample of the rock was placed in a culture medium. They believe that the bacteria were not terrestrial because they survived when the sample was sterilized at very high temperature and washed with alcohol. They also claim that the bacteria's DNA is unlike any on Earth. They presented a report on May 11, 2001, concluding that this is the first evidence of extraterrestrial life, documented in its genetic and morphological properties. Some of the bacteria they discovered were found inside meteorites that have been estimated to be over 4.5 billion years old, and were determined to be related to modern day Bacillus subtilis and Bacillus pumilus bacteria on Earth but appears to be a different strain.
Tantalizing clues from microbes in the Earth's stratosphere, where none should be alive, let alone on the tenuous but fierce winds, to what look like tiny bacteria in bits of a meteorite that fell from Mars to Earth's Antarctic.
Here's the Wiki article… The Origin of Life?