Biology
D epartment
6
H ighlight
One could argue that the age of genomes is divided
Jamie Gagnon Running with Scissors b y
D a v id
G .
P ace
“Let’s break a gene and see if you’re right about what it
between before CRISPR-Cas9 and after CRISPR-Cas9 (com-
does”, was pro forma.
monly referred to as “CRISPR”). As a Harvard post-doc
studying the genes involved in embryo development,
pick up where others had ended (and published), us-
James (Jamie) Gagnon remembers in 2012 that “pivotal
ing technology in a creative way to mark cells with a
moment” when these “really nice pair of scissors now easy
genetic barcode that could later be used to trace the
to make” came on the scene.
lineage of cells. Suddenly, they were using data sets of
CRISPR-scissor mutations to figure out how cells actu-
“Before CRISPR,” says Gagnon we were all using the earlier
Instead, the developmental biologist decided to
generation of genome editing tools. Even so, we were able
ally developed in zebrafish.
to determine that after making a mutation in a cell, when it
divided, the change that had been made was inherited.”
use the “scissors” in zebrafish, which then got him and his
collaborators thinking about using mutations to tell them
The new “scissors” rapidly scaled up genome editing,
In 2014 Gagnon published a paper describing how to
allowing researchers to more easily alter DNA sequences
how cells are related in embryos.
and modify gene function. At the same time CRISPR
inspired others to move from the research model of small
went from postdoc to principal investigator. In his lab at
organisms like the c. elegans, a transparent worm made
the Center for Cell and Genome Sciences, Gagnon curates
up of approximately 1,000 cells, to much larger ones like
10,000 fish in 1,000 controlled tanks that are carefully
zebrafish. “The power of genetics,” Gagnon says, “is that
labeled for experiments.
zebrafish are now genetically accessible as a model of
all vertebrates, including humans which share seventy
how does biology build an animal with millions of cells,
percent of genes with fish.”
all sharing information and all shape-shifting at the
same time? And how does science then best go about
The impulse for Gagnon’s current work in vertebrate
When Gagnon arrived at the U in January 2018, he
The prevailing question for Gagnon continues to be
lineage and cell fate choice involved the acknowledg-
studying that?
ment that “if we want to study how embryos grow, we
have to do it in a living animal.” At the time, he continues,
cacophony into a symphony that is the marvel of a
“everyone was mutating genes.” Perhaps still to this day,
living organism?
Furthermore, how does science turn chaos and
