Evolutionary age

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Latest revision as of 10:04, 24 August 2010

Evolutionary age of protein domains

(Based on this reference)

1. Error fetching PMID 16959887: [Reference]

Data

Pfam release 24.0 (2009. Oct)

• The Pfam database
  • ftp current_release
  • User manual (the pfam format)
  • Tip: use Mysql dump <- easy to handle the content

# download total DB (estimated ~2 days)
wget -c ftp://ftp.sanger.ac.uk/pub/databases/Pfam/current_release/database.tar &

• Loading into MySQL
  • Not all DBs were imported (only a few key DBs for this study)
  • pfamseq, genome_seqs(not available), ncbi_taxonomy, genome_species(not availabe), pfamA, gene_ontology
  • Release 24 - pfamseq, pfamA, ncbi_taxonomy, taxonomy, pfamA_reg_full_significant
    • in_full should "1"

The pfamA_reg_full_significant and pfamA_reg_full_insignificant tables contain,
as the names suggest, the significant and insignificant data respectively.
Significant hits are those with a bits score above the curated threshold for the family,
whilst insignificant matches are those that score below the curated threshold.
With respect to the tables that contain significant data (pfamA_reg_full_significant and
pfamA_reg_full), there is an extra column called 'in_full'.
The matches that are present in the full alignment for a Pfam family have this column set to 1,
while those that are not present in the full alignment have the 'in_full' column set to 0.
Where there is an overlapping fragment match and a full length match to the same Pfam-A family,
only one of the matches will be present in the full alignment for that Pfam-A family. 

mysql -u user -p
mysql>create DATABASE pfam24; \q
mysql -u user -p pfam24 < FULL_PATH/pfamseq.sql
mysql -u user -p
mysql>use pfam24
mysql>load data local infile 'pfamseq.txt' into table pfamseq FIELDS ENCLOSED BY "\'";

MySQL

• MySQL로 로딩시, 테이블 작성 순서대로 할것 - 에러발생 (작성하지 않은 테이블의 키인덱스 링크 관련 키워드)
  • loading time: a few hours
• Loading data file in background job
• Need to tune the database parameters <- it is very critical to process the calculation
  • innodb_buffer_pool_size
  • query_cache
  • query_buffer

mysql -u user -p'passwd' database < loadscript.sql &

R

• using R to analyze taxonomic distribution
  • see which fields should be used to link the databases...

Tree data

• Silva: SSU rRNA database

Results

• Species in Pfam (NCBI taxonomy): 148,925 species
• Genus (taxonomy): 31,949
  • taxonomy - browsing order in the web?
• MySQL query for the taxonomic distribution retrieval
  • pfamseq, pfamA, pfamA_reg_full_significant

# pfamA list
select distinct pfamA_id, auto_pfamA FROM pfamA;
# protein sequences of each auto_pfamA (pfamA_id)
select auto_pfamseq from pfamA_reg_full_significant WHERE auto_pfamA = '';
# taxonomic distribution
SELECT DISTINCT species,taxonomy,ncbi_code FROM pfamseq WHERE auto_pfamseq = 'auto_pfamseq';

SELECT DISTINCT species, taxonomy, ncbi_code FROM pfamseq seq, pfamA pf, pfamA_reg_full_significant sig \
       WHERE pf.pfamA_id='PF...' \
       AND sig.auto_pfamA=pf.auto_pfamA \
       AND seq.auto_pfamseq=sig.auto_pfamseq;

• Now, you have a list of Pfam having taxonomic distribution (ready to map)

Building the universal phylogenetic tree

• ncbitaxa.csv
  • total: 148925 (1 for column name)
  • non-blank: 148203
  • blank: 722
  • Eukaryota 106462
  • other sequences 191
  • Viruses 24643
  • 'unclassified' 1
  • Archaea 764
  • Bacteria 16102
  • unclassified sequences 40
  • max rank (in Archaea, Bacteria, Eukaryota): 22
  • ncbi_rank_taxa

create TABLE ncbitaxa ( SN INT, ncbi_taxid INT, species text, tax_rank text);
load data local infile 'ncbitaxa.csv' into table ncbitaxa FIELDS terminated BY ',' enclosed by '"' ignore 1 lines;

Silva

• /home/gnusnah/db/silva$SSURef_102_SILVA_NR_99.header - 262,092 lines
• paring SILVA NR set into ncbi taxid (Genbank) - "ACC_NCBI-taxon.txt"

## R
> tmp = scan("ACC_NCBI-taxon.txt",sep="\t",what="character")
Read 517708 items
> length(tmp)/2
[1] 258854
> tmp1 = matrix(tmp,length(tmp)/2,2,byrow=T)
> tmp1[1:2,]
     [,1]     [,2] 
[1,] "A16379" "730"
[2,] "A27627" "480"
> length(table(tmp1[,2]))
[1] 63916

• Procedure for building the universal tree

1. arb - editing NDS and exporting selected fields into a file (acc + taxid)
2. arb - exporting sequences into gb or fasta with gaps (alignments)
3. sorting out NR-taxid set corresponding to pfam taxid
4. collecting alignments for NR-taxid set (converting into phylip)
5. building tree (neighbor, mp, ml in phylip package)

Procedure

• Extract the taxonomic origins of each protein
• Get the Taxonomy info. of each origin
• Non-redundant (NR) set of taxonomic origins
• Collect all Small Subunit (SSU) rRNA sequences of the NR set
• Build the universal tree of life using SSU sequences
• Mapping the each protein belonging to a given domain into the universal tree
• Check which node is the most recent common ancestor (MRCA) node
• Calculate the branch length between MRCA and LCA (last common ancestor)