Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Residue profile in predivergence sequences as a guide to the origin of
  DNA replication   DNA dependent RNA polymerase core subunits abb' conserved residues at
frequencies most closely matched with codons at stage 10.4-11.1 in code
evolution. An excess of acidic residues (stage 2 additions) lowered this
estimate, but not by more than 2.3 stages. With 1 tryptophan (stage 14
addition) in 529 conserved residues, abb' significantly under-represented this
amino acid, consistent with a cut-off in its residue profile before completion
of the genetic code. Residue profiles in FEN-1 homologs and DNA topoisomerase
I-5' placed their origin at stage 11-13. Prokaryote septation protein, FtsZ,
arose earlier, between stage 8-11. Proteolipid in an ATP-driven proton pump
served as a marker for cell membrane formation. It indicated this event took
place near stage 7. Cell division, DNA replication and transcription were
inferred to have originated in a protocell antecedent of the last common
ancestor. Late-forming residue profiles characterized RNA dependent RNA
replicase, DNA polymerase, reverse transcriptase and ribonucleotide reductase.
This suggests some early processes, including RNA replication and
deoxynucleotide synthesis, once depended on catalysts not found in extant
residue sequences. Early formation of topoisomerase I, and enzymes that
synthesize and trim RNA-DNA hybrids was viewed as evidence for a mixed duplex,
with linear RNA and DNA strands, in the transition from an RNA to DNA genome.

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The categories of this paper are: eess
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
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The categories of this paper are: patt-sol
0
The categories of this paper are: hep-ph
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The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
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The categories of this paper are: quant-ph
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The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
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The categories of this paper are: nucl-ex