| Greengenes Goes Back To School
Greengenes (Greengenes.lbl.gov) is a website used by
biologists from around the globe to detect and classify microorganisms from
their local environments, based upon easily collected DNA samples. For example,
Eoin Brodie of Berkeley Lab’s Earth Sciences Division (ESD) is finding natural
soil bacteria that prevent toxic heavy metals from entering waterways. He can
rapidly analyze DNA samples from subsurface waters by comparing them against
the comprehensive Greengenes database hosted in Terry Hazen's Ecology
Department at Berkeley Lab. Greengenes is also aiding Berkeley Lab’s Yvette
Piceno in analyzing bacterial content in post-Katrina New Orleans flood waters,
and other microbiologists at Washington University in searching for intestinal
bacteria associated with human obesity. Another application, for DOE’s Mission
Focus on Biofuels, will aid in the discovery of microbial communities able to
convert cellulose into ethanol.
These projects and others, as well as the recent
publications about Greengenes in Applied and Environmental Microbiology and Nucleic Acids Research,
have caused the web servers to experience increased activity since Greengene's
inception in 2003. With a growing number of microbiologists turning to
Greengenes to classify their bacterial and archaeal sequences, there has been a
rise in questions from users new to the system. Many users have been confused
by the different software options available on the web to determine gene
sequences from raw chromatograms, or to align their sequences to each other or
to an annotated standard alignment. Others have been uncertain as to which tool
to use for taxonomic classification.
ESD’s Todd DeSantis, Greengenes’ database administrator (within
Gary Andersen's Molecular Microbial Ecology Group) turned to science education
expert, Jonathan Davies, from James Logan High School in Union City, California,
to develop a straightforward way for new users to find the website on-ramp. Davies
is a not only a 2006 Berkeley Lab CSEE Summer Fellow, but is also associated
with the Industry Initiatives for Science and Math Education (IISME). (IISME,
in its 27th year, places Bay Area teachers into research and industry settings
for the summer to make connections between the classroom and the science and
technology used by industry.)
In response to DeSantis’s request, Davies has created a
tutorial designed to lead a variety of users through the full series of steps
necessary to input their bacterial DNA sequences and receive a detailed
classification of those sequences back from the Greengenes database. The
tutorial project was conceived in spring of 2006 to expand usage of the
Greengenes technology to advanced high school and undergraduate biology
students. It has since grown to include a greater audience: anyone looking to
classify their bacterial DNA sequences, whether he or she is an experienced, casual,
or novice user. It currently includes sample data to allow the novice user a
chance to become familiar with the different files used and returned by
Greengenes. As well, the sample data can be used in conjunction with the
tutorial to try out the various steps in Greengenes, from aligning sequences up
to and through taxonomic classification. Along the way, users of the tutorial
will find vocabulary and acronyms explained with special links to explain some
concepts in greater detail. These include point mutations, chimeras as PCR
artifacts, and the six different taxonomies used by Greengenes for
classification.
As the tutorial continues to develop, lesson plans will be
available to educators to integrate the Greengenes technology directly into
their classrooms and laboratories. There will be a slide-show presentation to
introduce Greengenes’ taxonomic classification and its tutorial. A series of
lessons will be available to lead students through not only the steps covered
in the tutorial, but also the associated concepts and background information
necessary to successfully utilize the Greengenes technology. There will also be
lessons through which students can get an introduction to the concepts of
alignment and chimeras. For more information about using Greengenes as an
educational tool, please email Jonathan Davies (jsdavies@lbl.gov).
Since Greengenes is periodically expanding its capabilities,
the tutorial will grow in steps. For example, it will soon assist users in
designing DNA probes for rapid quantification of specific bacterial families. Bioinformatics
tools are being developed by ESD summer student, Nunut (Alex) Butarbutar, to
address this challenge. Other associated projects continue to develop, with new
data constantly being added to the Greengenes website. For example, Daniel Sam,
graduate student collaborator from U.C. Santa Cruz, is deploying on-line tools by
which researchers can compare the bacterial composition of urban aerosols by
time and location.
Note that Davies is one of seven IISME teachers who are
being hosted here at Berkeley Lab through the CSEE. Each summer, CSEE brings
teachers, pre-service teachers, and high school students to Berkeley Lab as
part of an outreach to cultivate the next generation of scientists.
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