Frequently Asked Questions
The human genome is the complete set of DNA containing all the information needed to build and maintain an individual human body which is made up of 3 billion DNA base pairs.
Genomics is the study of all the genes in the human genome. Genetic information is stored in DNA, which consists of a string of chemicals called base pairs. The order of base pairs on the string, called the “sequence”, determines the meaning of the genetic message. A gene is a specific stretch of bases that provides instructions for making a particular product, such as a piece of a hormone or enzyme. Humans have many thousands of genes, spaced across the entire set of DNA, which is packaged into 23 pairs of chromosomes.
Genetics usually refers to the study of individual genes and their role in disease or inheritance. Genomics refers to an individual’s entire genomic make-up. Genomics looks at the genetic sequence of genes, and their structure and function as well as the interactions between genes.
DNA is information stored as code, in a specific sequence, for building and maintaining the human body. Our bodies are made of trillions of cells. Inside each of those cells are chromosomes. In humans, we have 23 pairs of chromosomes. One chromosome of each pair comes from our mother (egg) and the other chromosome comes from our father (sperm). Each chromosome is composed of deoxyribonucleic acid (DNA). A simple analogy is that a person’s DNA serves as a blueprint for all of the information that makes us who we are. The DNA itself is organized into specific segments called genes, which encode proteins needed for our bodies to grow and function. The specific coding within the genes is composed through the use of only four specific DNA bases: A, T, G, and C.
It has only very recently been possible to have your genome sequenced, essentially providing a “map” of your personal genome, which is referred to as whole genome sequencing (WGS). Knowing more about your DNA will allow you to take steps towards living a healthier life.
The most comprehensive method of interrogating the 3.2 billion base pairs of the human genome is with Whole Genome Sequencing (WGS).
Genotyping services, like 23andMe, refers to the examination of specific bits of DNA that have a known function. For looking at many different variants at once, especially common variants, genotyping “chips” (note: verse actual Next Generation Sequencers) or arrays are typically used in the process of determining which genetic variants an individual possesses as an efficient and accurate option. These do, however, require prior knowledge of the variants you want to analyze.
Whole Genome Sequencing (WGS) is far more comprehensive, as it looks for variations across the entire genome and produces large amounts of data that can be used with additional consumer genomics applications available on the web to process out genetic variants of potential significance. Sequencing is used to both genotype someone for known variants, as well as identify variants that may be unique to that person.
The Exome represents less than 2% of the human genome, but contains a majority of the known disease causing variants making whole Exome Sequencing a cost effective alternative to whole genome sequencing. We believe 30x Whole Genome Sequencing (WGS) will be the defacto standard going forward.
While Exome Sequencing performs well detecting single nucleotide variants in the coding region, whole genome shows more uniform quality for the identification of those variants as well as insertions and deletions – making it potentially more powerful for detecting disease causing mutations.
A SNP is a DNA sequence variation that occurs in specific locations per individual. It appears approximately once every 1,000 instances in a DNA sequence and such small differences alter the genetic make-up of the person. These variations alter one’s eye color, skin color, race, appearance, body type, and susceptibility to diseases.
WGS has historically focused on clinical diagnosis applications, less attention has been given to it’s value in preventing disease and managing health. However, interest in WGS now as part of a individual preventative healthcare strategy is growing rapidly focusing on detecting disease early – when there is opportunity for treatment and improved outcomes.
Our genes are a part of who we are, so naturally they impact our health. By knowing more about your DNA, you may be able to take steps towards living a healthier life. WGS allows you to plan for the future by allowing you to learn if carrier for certain inherited conditions, so you can prepared. By finding out you have certain genetic risk factors, so you can make better lifestyle choices and appropriately monitor your health.