Launched
Human Genome Project
in 2008
By Andy Cheung
張文康
Life’s Lego
Blocks with
Dr. J. Craig
Venter
生物積木
—
克萊格·凡特博士
Observing
biological organisms
under a microscope reveals a realm of organisation
obscured to the naked eye. Regardless of the size of
the organism, its genetic makeup at the fundamental
level is composed of four nucleotide bases of DNA
– adenine, guanine, thymine and cytosine – the
biological blueprint to all things living. How small
can life actually be? Dr. J. Craig Venter, biochemist,
geneticist, entrepreneur and most notably pioneer to
the Human Genome Project, and his teamattempt to
answer this question.
Geneticists typically measure the complexity of
organisms by estimating the number of genes in a
genome and how the genes are arranged, instead
of their physical size. Referring to the collective noun
for all the genetic material of an organism, the
genome contains genes that code for instructions
to a particular step of life function. Living organisms
appear, behave and operate differently owing to
genes. To put things in perspective, a fruit fly consists
of about 13,600 genes and a human is estimated to
possess between 20,000 and 25,000 genes.
In an innovative procedure known as gene
designing, Dr. Venter and his research team deal
with synthesising a genome with only a minimal set
of genes required for the most basic of life forms. By
using synthetic biological techniques, they sorted
and removed redundant or non-essential genes,
beginning from
Mycoplasma mycoides
(a type of
bacteria) which consists of 525 genes. As a result,
they successfully created JCV-syn3.0, composed of
only 473 genes. In doing so, they were able to identify
the essential genes that can sustain life. The tricky
part is that gene functions are complex and subtle.
Tiny modifications could drastically change cell
functions and deem a cell unviable. In addition, the
monumental task of sorting out redundant genes for
the same essential function is compounded by the
fact that some genes must cooperate with others to
be effective.
Yet, even with JCV-syn3.0, there are 149 genes for
which Dr. Venter and his team have yet to precisely
define a function for.
“We had to be careful
to keep at least one gene for
each essential function”.
