Perhaps. Scientists studying the chemical composition of meteorites have discovered several nucleobases (the building blocks for DNA and RNA, which are by some theories essential to the early formation of life) that appear to have been of extraterrestrial formation, because they are rarely, if ever, seen on earth; the abstract of the report published online in the Proceedings of the National Academy of Science:
All terrestrial organisms depend on nucleic acids (RNA and DNA), which use pyrimidine and purine nucleobases to encode genetic information. Carbon-rich meteorites may have been important sources of organic compounds required for the emergence of life on the early Earth; however, the origin and formation of nucleobases in meteorites has been debated for over 50 y. So far, the few nucleobases reported in meteorites are biologically common and lacked the structural diversity typical of other indigenous meteoritic organics. Here, we investigated the abundance and distribution of nucleobases and nucleobase analogs in formic acid extracts of 12 different meteorites by liquid chromatography–mass spectrometry. The Murchison and Lonewolf Nunataks 94102 meteorites contained a diverse suite of nucleobases, which included three unusual and terrestrially rare nucleobase analogs: purine, 2,6-diaminopurine, and 6,8-diaminopurine. In a parallel experiment, we found an identical suite of nucleobases and nucleobase analogs generated in reactions of ammonium cyanide. Additionally, these nucleobase analogs were not detected above our parts-per-billion detection limits in any of the procedural blanks, control samples, a terrestrial soil sample, and an Antarctic ice sample. Our results demonstrate that the purines detected in meteorites are consistent with products of ammonium cyanide chemistry, which provides a plausible mechanism for their synthesis in the asteroid parent bodies, and strongly supports an extraterrestrial origin. The discovery of new nucleobase analogs in meteorites also expands the prebiotic molecular inventory available for constructing the first genetic molecules.
Does this really clear up any of the mysteries as to how life formed and evolution got rolling here on earth? No. It presents the possibility that life got its start with the delivery of pre-biotic chemicals (the nucleic acids contained in the meteors) from space, but that is all that it does. There was no report of little extraterrestrial creatures forming in the core of the meteorites, oozing out to colonize earth. All we have is the possibility, if the science can be properly replicated, that some of life’s building blocks were delivered to earth via meteorite. It offers a possible pathway for life to have developed, but that is all.
And the pathway is fraught with peril. None of the meteorites revealed the presence of cytosine, one of the nucleic acids used in building DNA and RNA, and as was explained in an earlier report (1999) by Robert Shapiro (whose book, Origins, A Skeptics Guide to the Creation of Life on Earth, 1987, I reviewed), cytosine is not susceptible to spontaneous, stable generation; the abstract of his report:
A number of theories propose that RNA, or an RNA-like substance, played a role in the origin of life. Usually, such hypotheses presume that the Watson–Crick bases were readily available on prebiotic Earth, for spontaneous incorporation into a replicator. Cytosine, however, has not been reported in analyses of meteorites nor is it among the products of electric spark discharge experiments. The reported prebiotic syntheses of cytosine involve the reaction of cyanoacetylene (or its hydrolysis product, cyanoacetaldehyde), with cyanate, cyanogen, or urea. These substances undergo side reactions with common nucleophiles that appear to proceed more rapidly than cytosine formation. To favor cytosine formation, reactant concentrations are required that are implausible in a natural setting. Furthermore, cytosine is consumed by deamination (the half-life for deamination at 25°C is ≈340 yr) and other reactions. No reactions have been described thus far that would produce cytosine, even in a specialized local setting, at a rate sufficient to compensate for its decomposition. On the basis of this evidence, it appears quite unlikely that cytosine played a role in the origin of life. Theories that involve replicators that function without the Watson–Crick pairs, or no replicator at all, remain as viable alternatives.
Without cytosine, life could not have arisen on the basis of DNA and/or RNA, at least not in the configurations in which they are today found. Whether or not the nucleic acids found on the meteorites are extraterrestrial, they still did not contain one of the necessary nucleic acids, cytosine, that between them, DNA and RNA employ in replicating life, and as Shapiro explains, the nucleic acid is not amenable to having been spontaneously generated.