Genomika: Informácie ku trackom

Informácie k predmetu Genomika

Na tejto stránke sú informácie k trackom ktoré budete vytvárať na browseri (obe skupiny). K niektorým trackom pridáme ďalšie informácie v nasledujúcich dňoch.

Comments to the task list

• Task (A) is a prerequisite of all other tasks, the rest are mostly independent of each other.
• Tasks are marked as fast (no significant computation required), medium (estimated computation up to 1 hour), slow (longer computation, possibly several hours).
  • These times are only estimates, reality may vary. Perhaps provide actual running times (approximate) in your documentation.
  • Fast tasks can be done entirely on genomika server.
  • Students having accounts on compbio research cluster may run medium and slow tasks there.
• If you get stuck on one task, you can try to do at least initial stages of another one. Coordinate within group!
• Document your work. Documentation should be independent of this page and of the documentation created last year - copy and modify relevant passages, cite sources.

Basic information on creating tracks

• https://github.com/fmfi-genomika/genomika-2017/wiki/Basics-of-creating-tracks
• https://github.com/fmfi-genomika/genomika-2017/wiki/How-to-add-track-to-DB-and-display-it-on-page
• Important: compared to last year, path /kentsrc/kent/src/hg/makeDb/trackDb/ was moved to /kentsrc/trackDb/

(A) Genome (fast)

• Download genome in fasta format, add to browser
• Data malGlo [1], malSym [2]
• https://github.com/fmfi-genomika/genomika-2017/wiki/Setting-up-a-Yarrowia-lipolytica
• Important step not described is to rename chromosomes/contigs to something reasonable
• Genome versions are numbered, we will start with malGlo1 and malSym1
• Missing part in last-year documentation - adding species to hgcentral database
  • look at existing records, e.g for yarLip1 to guess appropriate values
  • taxonomy ID can be found at https://www.ncbi.nlm.nih.gov/taxonomy

hgsql hgcentral -e '
insert into dbDb values (...);

insert into defaultDb values (...);

insert into genomeClade values (...);
'

(B) Protein coding genes and other items from the annotation (fast, needs A)

• Download genome annotation in GFF format, process to genepred format, split into two tracks: genes and other items
• Last year done by 2 groups based on 2 different databases:
• https://github.com/fmfi-genomika/genomika-2017/wiki/Protein-coding-genes-from-NCBI-RefSeq
• https://github.com/fmfi-genomika/genomika-2017/wiki/Protein-coding-genes-from-EnsembleFungi
• Coordinate with renaming chromosomes in step (1)
• Use appropriate IDs for naming genes
• Last-year tracks not ideal, try to improve
  • mRNA items in other item track are redundant, should be omitted
  • also items covering entire chromosome (type=region) should be omitted
  • protein coding genes could be displayed with codon highlighting - use the following settings in trackDb.ra:

baseColorUseCds given
baseColorDefault genomicCodons

(C) RepeatMasker (slow, needs A)

• Run RepeatMasker program to find repeated sequences (use fungi as species)
• https://github.com/fmfi-genomika/genomika-2017/wiki/RepeatMasker
• RepeatMasker and repeat library installed at compbio and genomika servers, or request a copy for your computer, registration may take several days

(D) tRNAscan-SE (medium, needs A)

• Run software for finding tRNA genes (for comparison with annotation)
• Download software from http://lowelab.ucsc.edu/tRNAscan-SE/ (already installed on compbio servers as tRNAscan-SE command)
• Convert output by script rna/tRNAscan-SEtoBED.py on github
• trackDb.ra record:

track tRNAs
shortLabel tRNA Genes
longLabel Transfer RNA Genes Identified with tRNAscan-SE
group genes
visibility hide
color 0,20,150
type bed 12
nextItemButton on
priority 10

(E) Augustus (slow, needs A)

• Run gene finder Augustus, create track with predicted genes (for comparison with annotation)
• Download and install software from http://bioinf.uni-greifswald.de/augustus/
  • Already installed on compbio servers
• Example of command line: augustus --uniqueGeneId=true --species=ustilago_maydis genome.fa > augustus.gtf
• ustilago_maydis is a related fungal species used for training parameters
• The result needs to be converted from gtf to genepred, by gtfToGenePred (at genomika server) with option -genePredExt
• If you name your track augustus, genome browser will recognize it automatically, no need to modify trackDb.ra

(F) Self-alignment (medium/slow needs A)

• The goal here is to find regions in the genome which have multiple approximate copies
• First we need to create local alignments of the genome to itself, then convert them to appropriate format
• Last year done by blastz: https://github.com/fmfi-genomika/genomika-2017/wiki/Self-alignments---self-chain---segmental-duplications
• This yeast I suggest using program last (ubuntu package last-align, website http://last.cbrc.jp/)
• Here is an example how I have done it in the past, it would be great to rewrite one-liners to some nicer script
  • ideally also patch the bug in pslToChain and submit the patch to the UCSC genome github

lastdb genome.fa genome.fa 
lastal genome.fa genome.fa -E 1e-20 > self.maf #slow part
maf-convert psl self.maf > tmpC.psl

# filter out trivial self-alignments as well as alignments shorter than 100bp in one of the two sequences or with identity less than 0.9
perl -lane 'die unless @F==21; $s=($F[9] eq $F[13] && $F[10]==$F[12] && $F[11]==0); $s = $s || $F[12]-$F[11]<100 || $F[16]-$F[15]<100 || $F[0]<0.9*($F[0]+$F[1]+$F[2]+$F[3]+$F[5]+$F[7]); print unless $s' tmpC.psl > tmpC100_90.psl
pslToChain tmpC100_90.psl tmpC100_90.chain # kent tools binary, available on genomika
# fix bad coordinates on reverse strand 
perl -lane 'if ($F[0] eq "chain" && $F[9] eq "-") { ($F[10],$F[11]) = ($F[8]-$F[11], $F[8]-$F[10]); print join(" ", @F) } else { print }' tmpC100_90.chain > self100_90.chain

# another chain for alignments with at least 70% identity and length at least 300bp
perl -lane 'die unless @F==21; $s=($F[9] eq $F[13] && $F[10]==$F[12] && $F[11]==0); $s = $s || $F[12]-$F[11]<300 || $F[16]-$F[15]<300 || $F[0]<0.7*($F[0]+$F[1]+$F[2]+$F[3]+$F[5]+$F[7]); print unless $s' tmpC.psl > tmpC300_70.psl
/projects2/dipMag/magCap-2017/assembly/magCapA/seq-tracks/pslToChain tmpC300_70.psl tmpC300_70.chain # kent tools binary copied from genome-dev
# fix bad coordinates on reverse strand 
perl -lane 'if ($F[0] eq "chain" && $F[9] eq "-") { ($F[10],$F[11]) = ($F[8]-$F[11], $F[8]-$F[10]); print join(" ", @F) } else { print }' tmpC300_70.chain > self300_70.chain

Parts of trackDb.ra (replace magCap5 with your genome name):

track selfChain100_90
shortLabel Self aln >90%id
longLabel Self alignments with length >100bp, identity >90%
group varRep
type chain magCapA5

track selfChain300_70
shortLabel Self aln >70%id
longLabel Self alignments with length >300bp, identity >70%
group varRep
type chain magCapA5

(G) Chains between genomes (medium, needs A from both groups)

• The goal is to create chains from malGlo to malSym and vice versa
  • Each group creates chains from its browser to the other browser
• This is done similarly as self-similarity chains, but alignments are done between two different genomes and filtering is done differently

lastdb genome.fa genome.fa 
lastal genome.fa genome2.fa -E 1e-20 > firstSecond.maf'
maf-convert psl firstSecond.maf > tmp.psl

# keep only alignments of length at least 100 in both sequences
perl -lane 'die unless @F==21; $s = $F[12]-$F[11]<100 || $F[16]-$F[15]<100; print unless $s' tmp.psl > tmp100.psl
pslToChain tmp100.psl tmp100.chain # kent tools binary on genomika
# fix bad coordinates on reverse strand 
perl -lane 'if ($F[0] eq "chain" && $F[9] eq "-") { ($F[10],$F[11]) = ($F[8]-$F[11], $F[8]-$F[10]); print join(" ", @F) } else { print }' tmp100.chain > firstSecond.chain

• trackDb.ra record similar, but include target species in line with type chain

(H) Protein-based chains between genomes (medium, needs A,B from both groups)

• In more distant species, DNA-based chains from part G are not sufficiently sensitive, but it is easier to find similarity between proteins
• In this type of track you extract protein sequences based on genome sequence and gene annotation, then you compare protein sets from the two species and map protein alignments back to the genome
• Commands from the last year create a psl file and load it. Then the alignments cannot be used to move between genomes. It would be better to convert psl to chain as in parts F and G.
• https://github.com/fmfi-genomika/genomika-2017/wiki/Chains-from-protein-alignments

(I) Genomes for comparative genomics (fast, only one group)

• Download genomes of additional Malassezia species (other than malGlo and malSym)
• Use list here [3]
• Rename chromosomes similarly as in A, name fasta files in a systematic way (malRes1.fa etc.)
• Store files in a directory at genomika server

(J) Multiple whole-genome alignment (slow, needs A from both groups, I)

• TODO: more info
• The goal of this track is to create a whole-genome multiple alignment of several genomes
• Use genomes from part I as well as malGlo and malSym genomes from the browser
• Beware that malSym1 and malGlo1 should be correctly named, both the genome as a whole and their chromosomes as in the browser
• The task requires some preprocessing - renaming things etc (fast), alignment computation (slow, we recommend running on compbio servers) and postprocessing (fast/medium)
• The notes from the last year consist of three parts: general intron, Brona's notes (Example of use of tba in a different project), and student notes (Example of use of tba in a our project, display alignments).
  • Probably follow student notes.
  • The notes are not finished (end with "track does not work"), but the track was finished, see track "S. Align (L)" in sacCer3 browser. See final version of sacCer3 trackDb.ra on genomika server.
• To run alignment, you need phylogenetic tree of these species. Try to find one in literature, e.g Fig 3 in [4]
• https://github.com/fmfi-genomika/genomika-2017/wiki/Alignments

(K) Conservation by phyloP (medium, needs A,I,J)

• TODO: more info
• https://github.com/fmfi-genomika/genomika-2017/wiki/PhyloP-tracks

(L) Conserved elements by phastCons (medium, needs A,I,J)

• TODO: more info
• https://github.com/fmfi-genomika/genomika-2017/wiki/Conservation

(M) Protein domain and other protein annotation from Uniprot (medium, needs A,B)

• TODO: more info
• https://github.com/fmfi-genomika/genomika-2017/wiki/Uniprot-data

(N) Expression data from RNA-seq (medium/slow, needs A)

• TODO: more info
• https://github.com/fmfi-genomika/genomika-2017/wiki/Expression-tracks

(O) Differences between strains (slow, needs A)

• TODO: more info
• https://github.com/fmfi-genomika/genomika-2017/wiki/Strain-comparison