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<back>
<ack>
<p>We are grateful to Uri Alon, Harley McAdams, Lee Kroos,
Patrick Piggot, and Patrick Stragier for critical comments of 
the manuscript. ...</p>
...
</ack>
<fn-group>
<fn id="n1" fn-type="conflict">
<p><bold>Conflicts of interest.</bold> The authors 
have declared that no conflicts of interest exist.</p>
</fn>
<fn id="n2" fn-type="con">
<p><bold>Author contributions.</bold> PE, MF, STJ,
EMC, DZR, TS, JSL, and RL conceived and designed the
experiments. PE, MF, DZR, STW, CF, and KH performed
the experiments. PE, MF, STJ, EMC, DZR, and JSL
analyzed the data. PE, MF, STJ, EMC, DZR, and JSL
contributed reagents/materials/analysis tools. PE,
MF, STJ, EMC, JSL, and RL wrote the paper.</p>
</fn>
</fn-group>
...
</back>
...

<article dtd-version="1.1d1">
...
<back>
<ref-list>
<ref>
<element-citation>
<person-group>...</person-group>
<source>Nature (London)</source>
<year iso-8601-date="2001">2001</year>
<volume>411</volume>
<fpage>498</fpage>
<lpage>501</lpage>
<pub-id pub-id-type="pmid">11373685</pub-id>
</element-citation>
</ref>
...
</ref-list>
<fn-group>
<fn>
<p>This paper was submitted directly (Track II) to the PNAS
office.</p>
</fn>
<fn id="FN153">
<p>&#x00A7; Barta, A., Dorner, S., Polacek, N., Berg, J. M.,
Lorsch, J. R., Nissen, P., Hansen, J., Muth, G. W. &#x0026; Ban, N.
(2000) <italic>Science</italic> <bold>291</bold>, 203a (abstr.).</p>
</fn>
</fn-group>
</back>
</article>