went to college thinking I would be a math major. Then one
day I happened to hear a lecture by a professor named James
D. Watson. Jim Watson, along with Francis Crick, was the discoverer
of the structure of DNA, the molecule that genes are made
of. At the end of the hour, I was not a math major. I was
in love with DNA- for life. The field I had discovered was
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Secret of Life
was clear that DNA and this new field of molecular biology
held the secret of life. Genes are lengths of those long,
stringy, DNA molecules, and each gene carries- in code- the
information to make one protein. Each protein is a complex
molecular device that carries out a specific task within a
cell. Collectively, our proteins make us what we are. It was
apparent to all of us lucky enough to stumble into that classroom
that if you understood how genes and their proteins worked
you would understand life at the molecular level, and one
day -some day- you could even answer every interesting question
you had ever wanted to ask about being human. For example:
How do you make a hand? What is a memory? How does a cell
become cancer? Why do I look like my mother? It was the possibility
of finding the answers to these questions that was totally
intoxicating, totally passion provoking. Addictive.
my own case, the fascination sparked by one undergraduate
class has led me to a laboratory at MIT that today is full
of zebrafish. Zebrafish are small, 2-inch long fish from the
Ganges River. Why zebrafish?
am a developmental biologist. The question that fascinates
developmental biologists is simple but profound, How does
a single cell, the fertilized egg, develop into an animal?
Early developmental biologists realized that this amazing
event involves three cellular processes. First, the fertilized
egg cell has to divide to make billions of cells. Second,
the cells have to differentiate into many types- skin cells,
muscles cells, eye cells, et c. Third, the cells have to take
up the correct position in 3D space- a process called pattern
How do you make a hand? What is a memory? Why do I
look like my mother?
my hand and foot. They are about the same size. They both
contain the same cell types- skin, bone, muscle, and blood.
But they are different shapes, due to the process of pattern
formation. Without pattern formation, development would not
produce an animal. It would yield a blob.
triumph of modern biology has been to demonstrate that it
is genes - acting through the proteins they encode - that
tell cells when and how to divide. It is genes that tell cells
how to become different types and it is genes that instruct
cells how to form specific shapes and structures. The goal
of developmental biology now is to identify the genes that
do this in vertebrate animals and then to find out how they
zebrafish are more similar to humans than they appear.
course, our first choice of organisms to study would be humans.
But we find that humans seldom volunteer for the type of experiments
biologists do. Some of our experiments require that you de-construct
the organism. Yet others require that the animals mate whenever
and to whomever we request. Any volunteers? I thought not.
But as you will see, we can study human genes by studying
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Photos: N. Hopkins; Rolf Karlstrom - University of Massachusetts,
Amherst and Don Kane - University of Rochester