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Unformatted text preview: heir cells. symbiosis? 24
Thursday, December 6, 12 How to study microbes
• Key questions about microbes in environment: Who are they? (i.e., what kinds of microbes are they) What are they doing? (i.e., what functions and
processes do they possess) 25
Thursday, December 6, 12 Studying the microbe-like entities in the aphid gut Field Observations
not exceptionally helpful because the
appearance of microorganism is not a
good indicator of "what they are"
appearance is very homoplastic Appearance of
Thursday, December 6, 12 Studying the microbe-like entities in the aphid gut Culturing Field Observations great plate anomaly:
can't grow a lot of the
microbe (that lives in the
aphids' gut) in the lab Key bacteria in
aphid gut have
not been cultured Appearance of
27 Thursday, December 6, 12 Studying the microbe-like entities in the aphid gut DNA
CSI-style Culturing Key bacteria in
aphid gut have
not been cultured Field Observations Appearance of
28 Thursday, December 6, 12 • Who Are They? 29
Thursday, December 6, 12 PCR and phylogenetic analysis of rRNA genes
of copies of
sample PCR sample run a PCR Phylogenetic tree
rRNA1 Sequence alignment = Data matrix Yeast C A C A C T A C AG AGA C T AG rRNA1
GATCGA... 3’ T E. coli
Humans A Yeast E. coli rRNA1 Sequence
rRNA genes Humans A T build an alignment AG
T build a tree:
it can tell you what kind of organisms there
in the sample 30
Thursday, December 6, 12 31
Thursday, December 6, 12 related to E.Coli (in the same family) 32
Thursday, December 6, 12 • What Are They Doing?
it doesn't really tell us the function b/c microbe can change pretty rapidly (even though they are in the same family)
in order to know, we use experimental study.
a new way is to sequence the WHOLE genome and not just the ribosomal...
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This document was uploaded on 04/13/2013.
- Fall '08