Origin of life on Earth

A new study finds that a pair of chemical building blocks similar to those in genetic material was present in a meteorite before it fell to Earth in the 1960s. Researchers say the finding makes it slightly more plausible that meteorite bombardments may have seeded ancient Earth with life's raw materials, potentially paving the way for life itself.Part of the scientific mystery of how life emerged is the origin of chemical building blocks: Were they created by chemical reactions on Earth or did they, perhaps, hitch rides on meteorites that may have germinated our and other planets in our solar system with the same molecules? By studying meteorite fragments, such as those that fell in 1969 near the town of Murchison, in the southeastern Australian state of Victoria, researchers have learned that they contain carbon-based compounds that most likely formed in space, including sugars and amino acids.They were not sure, however, about a class of compounds called nuclease, which when fused with sugar molecules are the building blocks of nucleic acids such as DNA (the stuff of genes) and its close cousin RNA (produced when genes switch on). Thus it is unsure that whether the life on Earth was really originated this way.