Biochemists have to be good communicators. Whether it's in a lab
or in an academic setting, you have to be able to explain your ideas to a
wide audience. For example, if you work in a university, you'll have to explain
-- even sell -- your research idea to private industry, government or nonprofit
organizations in order to secure funding to finance the project.
For
years, biochemists have been comparing proteins from different species and
recording the changes that have occurred through evolution. Think of it as
creating a genetic family tree!
Imagine you're a biochemist looking
to expand the research you have done in this field.
MOLECULAR
EVOLUTION
Just How Old is That DNA, Anyway?
Robert F. Service
A
handful of research groups have reported recovering DNA from insects trapped
in amber and even dinosaurs entombed in coal -- samples as old as 135 million
years. But skeptics have shot back that intact DNA from old sources is more
likely to be from some modern interloper in the sample, such as bacteria.
Now,
researchers have an independent test of ancient DNA authenticity. Below, an
international team reports that a chemical change that converts amino acids
in proteins from one mirror-image form to another -- a process known as racemization
-- takes place at virtually the same rate as the degradation of DNA.
If
amino acids in a sample show this conversion to even a modest degree, the
original DNA is likely long gone. Any remaining genetic material should be
a contaminant. When the researchers used this test on a variety of ancient
DNA samples, they found that only those from insects trapped in amber appear
to stand the test of time.
Volume 272, Number 5263, Issue of 10
May 1996, p. 810
(c)1996 by The American Association for the
Advancement of Science.
REPORTS
Amino Acid Racemization
and the Preservation of Ancient DNA
Hendrik N. Poinar, Matthias Hoss,
Jeffrey L. Bada, Svante Paabo
The extent of racemization of aspartic
acid, alanine and leucine provides criteria for assessing whether ancient
tissue samples contain endogenous DNA. In samples in which the D-L ratio of
aspartic acid exceeds 0.08, ancient DNA sequences could not be retrieved.
Paleontological
finds from which DNA sequences are purportedly millions of years old have
been reported show extensive racemization, and the amino acids present show
extensive racemization, and the amino acids present are mainly contaminates.
An exception is the amino acids in some insects preserved in amber.
Imagine
these summaries explain the focus of your research. You are applying for a
six-month government research grant. Write a 250-word introductory letter
outlining your research and findings. Explain why you think the government
should back your research. Feel free to consult other sources in your library.
Remember -- no funding, no research.