Most people have heard of the Human Genome Project—the massive scientific project to sequence human DNA that culminated in the 2001 publication of the first human genetic code. But have you heard of the Human Cell Atlas?
The effort involves over 480 scientists working on 185 projects to catalogue the estimated 37.2 trillion cells in the human body by sequencing at least 10 billion cells of all the tissues, organs and systems. By studying the genetics of each cell, researchers hope to better understand what makes them tick.
Compiled by researchers at MIT’s Broad Institute, the info comes from human umbilical cord blood and adult bone marrow cells. Sequencing thousands of individual cells, however, is not an easy task. According to a press release, the researchers used new computational methods to quickly identify cell types in the sequencing data as well as identify the genetic fingerprint for different cells. They also studied cellular development.
Those new tools allowed the scientists to tackle 224,000 bone marrow cells collected from four adult patients—about 100 times as many cells as most cell-sequencing experiments handle. The team sequenced a similar number of cells from the cord blood.
“Collecting and processing half a million immune cells was a Herculean feat, involving tightly coordinated teamwork across many areas of expertise,” Broad Institute team member Danielle Dionne says in the release.
This latest data release joins two prior sets from the Human Cell Atlas: a 2,000-cell sample from the human spleen and 6,639-cell sample from the mouse lymph node. This new half-a-million cell dataset is magnitudes larger and will soon be eclipsed by another dataset of 1.08 million cord blood, bone marrow and white blood cells that the Broad Institute will soon release. Another 250,000 human developmental cells have also been sequenced by an Atlas collaborator, but have not yet been made public.
In all, the data is a solid first step toward the analysis of 10 billion cells. The Consortium's initial goal is to produce a first draft of the Atlas that details 30 million to 100 million cells.
As Steve Connor at MIT Technology Review explains, the Cell Atlas will accomplish three major things. First, it will create a super-accurate 3D map of where different cell types reside in the human body. It will also reveal which genes are active within each cell, helping researchers understand how tissues develop and operate at a genetic level. And third, the research will likely reveal new types of tissue.
Until now, researchers have identified about 300 different types of cells in the human body, including things like fat cells and neurons. But in recent years, new molecular analyses have revealed types of tissue researchers previously missed, including two new types of retinal cells and a new immune cell that produces an immune-surpressing steroid.
It’s likely the Atlas will uncover many more new tissue types. “We will see some things that we expect, things we know to exist, but I’m sure there will be completely novel things,” says Mike Stubbington, of the Sanger Institute in the U.K., which is a major collaborator in the project. “I think there will be surprises.”
The ultimate goal of the open-source Atlas is to accelerate discoveries by medical researchers and biologists around the world, who will use the information to study cell development and create a new era of precision medicine with highly targeted drugs and treatments.