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 MESOZOIC ERA. The Mesozoic era is commonly subdivided into three geologic periods: Triassic (252 to 201.3 million years ago). Jurassic (201.3 to 145 million years ago). Cretaceous (145 to 66 million years ago). The Mesozoic era begins in the wake of the largest extinction in Earth's history. This extinction took place 252 million years ago and resulted in 96% of marine life and 70% of terrestrial life dying out.