GNN Home. Genome sequencing is figuring out the order of DNA nucleotides, or bases, in a genomethe order of As, Cs, Gs, and Ts that make up an organism's DNA.The human genome is made up of over 3 billion of these genetic letters.hen you read a sentence, the meaning is not just in the sequence of the letters. It is also in the words those letters make and in the grammar of the language. Similarly, the human genome is more than just its sequence.
This blog entry thus provides a basic overview of the four Geologic Eras. The Precambrian Era (4.6 billion years ago to 600 million years ago) encompasses the great majority of Earth's geologic history, stretching from the formation of our planet to the appearance of shelled marine life.
The Precambrian covers almost 90% of the entire history of the Earth. It has been divided into three eras: the Hadean, the Archean and the Proterozoic. Source: Unknown. The Precambrian Era comprises all of geologic time prior to 600 million years ago. The Precambrian was originally defined as the era that predated the emergence of life in the Cambrian Period. It is now known, however, that life on Earth began by the early Archean and that fossilized organisms became more and more abundant throughout Precambrian time. The two major subdivisions of the last part of the Precambrian are the Archean (oldest) and the Proterozoic.