An Introduction and Some Definitions
This is a podcast about the biggest explosion in biological knowledge in human history and it is has been happening all around us over the last 30 years. The Genomics Revolution is based on 1) some basic knowledge about DNA – how it is structured and faithfully replicated, 2) an ambitious goal to fully understand the complete genetic basis of human biology, 3) new ways to store, collate, and compare incredibly large data sets, and 4) lots of determined biologists, chemists, computer scientists, and statisticians working together in new collaborations that have smashed holes in academic disciplines and forged new interdisciplinary/multidisciplinary academic departments and biotechnology companies.
Yet what is genomics? It is simply put the study of a genome or all the DNA of a cell or organism of interest. You and I have grown up knowing what DNA is, both as the hereditary material passed from one generation to the next and as a specific biological polymer – a double helix of strands each made up of units we know by their shorthand names – A’s, C’s, G’s, and T’s, linked together in a strand by strong bonds while the two strands interact to form the double helix using relatively weak bonds. You and I have also grown up knowing that what a gene is – a stretch of DNA sequence that tells a cell to do something. By “do something”, I mean that the DNA sequence of a gene tells a cell to make a copy of that DNA as RNA, a shorter-lived single stranded polymer where T’s are replaced by U’s. In most cases, the RNA made from a gene carries a code for making a very different polymer – a linear protein sequence made up of amino acid residues linked together. Proteins do most of the work of cells, but genes tell a cell what proteins to make. A genome is composed of all the genes of a given cell or organism along with some DNA that does not act as genes. That extra DNA is also important in other ways that we will discuss in a later episode.
So DNA makes up a gene and all the genes in a cell plus some extra DNA equals a genome. That is a lot of information, usually 400,000 base pairs of DNA or more in the genomes of cellular organisms and the more can range up into the billions of base pairs for organisms such as we humans or corn plants. In future episodes, we will see why scientists wanted all of information, how they figured out the most efficiently ways to obtain the information, and how they came up with different ways to analyze the information. We will also start to talk about specific genomes, why we care about them, what they teach us about how genomes and organisms work, and how we might use that information to solve problems in healthcare, agriculture, or bio-energy. We will also see how we can add layers of additional information onto a given genome. For example, all of the RNAs made from a genome through the cellular process of transcription is called the transcriptome, while all of the proteins made based on the genes in a genome are called the proteome. There are many other “-omes” out there to be explored. Finally, we will consider the combined genomes of many organisms, typically microbes, that live in a particular habitat or community. Such metagenomes, literally meaning “above one genome”, have identified new organisms we could not identify earlier because we could never grow them. All of this sounds complex, but we will break it down into understandable 10-20 minute segments.
I hope you keep listening to future episodes of Genomics Revolution. Talk to you again soon.