About Genomics

So, what is Genomics? Genomics is the study of the DNA, Genes, and Chromosomes which make up the complete set of genetic instructions, the genome, contained within nearly every cell in your body. But, as with so many questions in science, this answer leads to new questions. So, perhaps we should take this one step at a time…

DNA
The best way to think of DNA is as a long molecule made of a chain of 4 smaller molecules called nucleotides, symbolized by the letters, A, T, C, and G. These letters store instructions on how to make proteins and ultimately, how to make you. Our DNA molecules are organized into a double helix structure which resembles a spiral staircase. However, with this staircase, there are certain rules that dictate which letters can sit across from each other on each step, rules which help in reading and replicating your DNA instructions. The rules strictly require that the letter “A” must be opposite the letter “T”, and the letter “G” opposite the letter “C”. In this way, it is possible to read one half of the “staircase” and know precisely what the other half should look like. In fact, this is the basic idea behind how your DNA is copied when your cells divide.

Genes
Genes are simply long sequences of DNA “letters” which provide instructions for making protein and proteins perform countless tasks within your cells, from providing structural support, to breaking down waste. It is the sequence of the DNA “letters” within each gene that affects the way the instructions are interpreted in terms of the proteins that are produced. This is analogous to the manner we interpret words on a page. For example, the same four letters are in the words, “mate” and “team,” but the sequence of the letters affects our interpretation of their meanings. On the other hand, sometimes a difference in a genetic sequence does not lead to a change in the protein. The analogy holds with words like, “color” and “colour” for example. These words have different spellings but are interpreted identically.

Chromosomes
As we move from DNA to Genes and from Genes to Chromosomes, we are basically zooming out from a highly magnified view of your DNA to a much wider view. Scientifically speaking, Chromosomes are extremely long interwoven and highly coiled pieces of DNA, the longest continuous pieces of DNA in our cells. But, if we carry the previous analogy of genes resembling words and sentences a little further, then it follows that chromosomes can be thought of as complete chapters in the story of you. They are composed of many words (genes), they have a clear beginning and ending, and to an extent they can stand alone as a discrete unit that tells part of the story of your life.

Genome
As we zoom further out from individual DNA molecules, past the chromosome level, we can see that we have multiple chromosomes, 46 to be exact (23 pairs), and the summation of these chromosomes make up what is considered to be your genome. You can then infer that your genome is composed of all your DNA, Genes, and Chromosomes and it follows that Genomics is the study of these three levels of genetic material. Going back to our analogy, you can think of your genome as being analogous to your complete autobiography. It consists of 23 chapters, albeit with two copies of each one, and it tells the complete story of you.

SNP's
SNP is short for Single Nucleotide Polymorphism and is pronounced “snip” but, it's not as complicated as it sounds. As previously mentioned, a nucleotide is simply one of the four letters of DNA, A, T, C, or G. The word Polymorphism is really just a fancy way of saying, “many forms”. Therefore, a single nucleotide polymorphism is just a single letter of DNA, in a specific location, that can take many forms, i.e. it can be an A, T, C, or G. SNP's are significant to scientists because the vast majority of human DNA, from one individual to the next, is the same at a given location. Therefore, it is these SNP’s, these places that vary by a single letter, which differentiate individuals and to a large extent, account for the unique characteristics of you. SNP’s amount to a single-letter change in the spelling of a “protein word” and as we noted earlier, sometimes a change alters the meaning of the word and sometimes it doesn’t but, in either case, SNP’s can tell us a small part of your genetic story.