While genetics is the study of individual genes, genomics is the study of all of the genes found within a particular cell or organism (National Human Genome Research Institute). By studying all of the genes within a genome, we can gain a better understanding of the sequence of each of these genes, their relative locations within the genome, and what they code for within the cell.  

Perhaps the most famous example of genomics research is the Human Genome Project where scientists successfully sequenced the entire human genome for the first time. Understanding the full sequence of a genome tells us valuable information about which genes a cell could express. However, not all genes in a cell’s genome are expressed all of the time. Instead, most genes are turned “on” and “off” at different points in a cell’s life cycle. Gene expression can not only vary across time but can also differ between different types of cells within the body. For example, the cells that make up your heart express different genes than the cells that make up your skin.  

While genomics allows us to study which genes a cell could express, we have to rely on other methods, such as transcriptomics or proteomics, to determine which genes a cell is actually expressing at a given point in time. 

Transcriptomics is the study of all of the RNA transcripts found within a cell at a given point in time. This includes measuring coding RNA, which is RNA that will be translated into a protein, and non-coding RNA, which carries out a separate function without necessarily being translated into a protein.  

 By sequencing all of the RNA found within a cell, we can work “backwards” and determine which gene each molecule of RNA was transcribed from. Transcriptomics not only evaluates which RNA molecules are present/absent in a cell but also the quantity of the RNA molecules.  

For example, if we are measuring RNA transcripts within a hypothetical cell, we might find twice the amount of RNA transcripts from gene A compared to the RNA transcripts from gene B. This information allows us to infer that at the point in time when we measured the RNA within this cell, the cell was expressing gene A twice as much as gene B. If the functions of gene A and gene B are known, we can then use these data on their relative expression to infer what internal processes were taking place at the time when the cell was sampled.   

At the Allen Institute, we use transcriptomics for multiple lines of research—including our efforts to map the human brain and map the healthy human immune system.  

Proteomics refers to the study of all of the proteins within a given cell and/or organism. A proteome refers to the entire list of proteins made by a cell.

Proteins carry out the majority of functions and activities that take place within a living system. For example, insulin, which helps regulate our blood sugar levels, hemoglobin, which helps carry oxygen within our blood, and antibodies, which help the immune system fight foreign pathogens, are all examples of proteins that perform vital functions for our health and wellbeing.  

Because proteins are responsible for so many vital functions within a given cell, system, and/or organism, studying proteomics helps us gain insight into the processes, mechanisms, and/or pathways that are critical to health and disease.  

Similarly to transcriptomics, proteomics not only evaluates which proteins are present/absent in a living system at a given point in time, but also how much of these proteins are present. If we measure proteins within a hypothetical cell, we might find twice as much of protein A compared to protein B. These data tell us that gene A, which is transcribed and then translated into protein A, is being expressed roughly twice as much as gene B.  

Knowing which proteins are more or less abundant within a cell and/or organism can be extremely helpful when studying health and disease. For example, our scientists have used proteomics in multiple lines of research, including our efforts to better understand long COVID.