Schema for Placental Chain/Net - Non-primate Placental Mammal Genomes, Chain and Net Alignments
  Database: hg38    Primary Table: chainMm10    Row Count: 3,678,476   Data last updated: 2015-04-09
Format description: Summary info about a chain of alignments
fieldexampleSQL type description
bin 585smallint(5) unsigned Indexing field to speed chromosome range queries.
score 170460double score of chain
tName chr1varchar(255) Target sequence name
tSize 248956422int(10) unsigned Target sequence size
tStart 11677int(10) unsigned Alignment start position in target
tEnd 37616int(10) unsigned Alignment end position in target
qName chr6varchar(255) Query sequence name
qSize 149736546int(10) unsigned Query sequence size
qStrand -char(1) Query strand
qStart 28206106int(10) unsigned Alignment start position in query
qEnd 28238509int(10) unsigned Alignment end position in query
id 2478int(10) unsigned chain id

Connected Tables and Joining Fields
        hg38.chainMm10Link.chainId (via chainMm10.id)
      hg38.netMm10.chainId (via chainMm10.id)

Sample Rows
 
binscoretNametSizetStarttEndqNameqSizeqStrandqStartqEndid
585170460chr12489564221167737616chr6149736546-28206106282385092478
58524809chr12489564221217613467chr1794987271+6614926266150817430118
585123798chr12489564221281529547chr1794987271-28866318288757794969
58519591chr12489564225233353327chr14124902244-7475327474754272659931
58524745chr12489564225237253365chr2182113224+111499215111500233432195
58524960chr12489564225237253365chr2182113224+111527223111528241425148
58530439chr12489564225237553366chr2182113224-7020024170201235284109
58516862chr12489564225237953329chr2182113224-7077709570778050861194
58512706chr12489564225238053329chr2182113224-92537432925383961441674
5857964chr12489564225238152664chr2182113224-70261323702616002318598

Note: all start coordinates in our database are 0-based, not 1-based. See explanation here.

Placental Chain/Net (placentalChainNet) Track Description
 

Description

Chain Track

The chain track shows alignments of human (Dec. 2013 (GRCh38/hg38)) to other genomes using a gap scoring system that allows longer gaps than traditional affine gap scoring systems. It can also tolerate gaps in both human and the other genome simultaneously. These "double-sided" gaps can be caused by local inversions and overlapping deletions in both species.

The chain track displays boxes joined together by either single or double lines. The boxes represent aligning regions. Single lines indicate gaps that are largely due to a deletion in the human assembly or an insertion in the other assembly. Double lines represent more complex gaps that involve substantial sequence in both species. This may result from inversions, overlapping deletions, an abundance of local mutation, or an unsequenced gap in one species. In cases where multiple chains align over a particular region of the other genome, the chains with single-lined gaps are often due to processed pseudogenes, while chains with double-lined gaps are more often due to paralogs and unprocessed pseudogenes.

In the "pack" and "full" display modes, the individual feature names indicate the chromosome, strand, and location (in thousands) of the match for each matching alignment.

Net Track

The net track shows the best human/other chain for every part of the other genome. It is useful for finding orthologous regions and for studying genome rearrangement. The human sequence used in this annotation is from the Dec. 2013 (GRCh38/hg38) assembly.

Display Conventions and Configuration

Chain Track

By default, the chains to chromosome-based assemblies are colored based on which chromosome they map to in the aligning organism. To turn off the coloring, check the "off" button next to: Color track based on chromosome.

To display only the chains of one chromosome in the aligning organism, enter the name of that chromosome (e.g. chr4) in box next to: Filter by chromosome.

Net Track

In full display mode, the top-level (level 1) chains are the largest, highest-scoring chains that span this region. In many cases gaps exist in the top-level chain. When possible, these are filled in by other chains that are displayed at level 2. The gaps in level 2 chains may be filled by level 3 chains and so forth.

In the graphical display, the boxes represent ungapped alignments; the lines represent gaps. Click on a box to view detailed information about the chain as a whole; click on a line to display information about the gap. The detailed information is useful in determining the cause of the gap or, for lower level chains, the genomic rearrangement.

Individual items in the display are categorized as one of four types (other than gap):

  • Top - the best, longest match. Displayed on level 1.
  • Syn - line-ups on the same chromosome as the gap in the level above it.
  • Inv - a line-up on the same chromosome as the gap above it, but in the opposite orientation.
  • NonSyn - a match to a chromosome different from the gap in the level above.

Methods

Chain track

Transposons that have been inserted since the human/other split were removed from the assemblies. The abbreviated genomes were aligned with lastz, and the transposons were added back in. The resulting alignments were converted into axt format using the lavToAxt program. The axt alignments were fed into axtChain, which organizes all alignments between a single human chromosome and a single chromosome from the other genome into a group and creates a kd-tree out of the gapless subsections (blocks) of the alignments. A dynamic program was then run over the kd-trees to find the maximally scoring chains of these blocks. Chains scoring below a minimum score of '5000' were discarded; the remaining chains are displayed in this track. The linear gap matrix used with axtChain:

-linearGap=loose

tablesize    11
smallSize   111
position  1   2   3   11  111  2111  12111  32111  72111  152111  252111
qGap    325 360 400  450  600  1100   3600   7600  15600   31600   56600
tGap    325 360 400  450  600  1100   3600   7600  15600   31600   56600
bothGap 625 660 700  750  900  1400   4000   8000  16000   32000   57000
See also: lastz parameters used in these alignments, and chain minimum score and gap parameters used in these alignments.

Net track

Chains were derived from lastz alignments, using the methods described on the chain tracks description pages, and sorted with the highest-scoring chains in the genome ranked first. The program chainNet was then used to place the chains one at a time, trimming them as necessary to fit into sections not already covered by a higher-scoring chain. During this process, a natural hierarchy emerged in which a chain that filled a gap in a higher-scoring chain was placed underneath that chain. The program netSyntenic was used to fill in information about the relationship between higher- and lower-level chains, such as whether a lower-level chain was syntenic or inverted relative to the higher-level chain. The program netClass was then used to fill in how much of the gaps and chains contained Ns (sequencing gaps) in one or both species and how much was filled with transposons inserted before and after the two organisms diverged.

Credits

Lastz (previously known as blastz) was developed at Pennsylvania State University by Minmei Hou, Scott Schwartz, Zheng Zhang, and Webb Miller with advice from Ross Hardison.

Lineage-specific repeats were identified by Arian Smit and his RepeatMasker program.

The axtChain program was developed at the University of California at Santa Cruz by Jim Kent with advice from Webb Miller and David Haussler.

The browser display and database storage of the chains and nets were created by Robert Baertsch and Jim Kent.

The chainNet, netSyntenic, and netClass programs were developed at the University of California Santa Cruz by Jim Kent.

References

Chiaromonte F, Yap VB, Miller W. Scoring pairwise genomic sequence alignments. Pac Symp Biocomput. 2002:115-26. PMID: 11928468

Kent WJ, Baertsch R, Hinrichs A, Miller W, Haussler D. Evolution's cauldron: duplication, deletion, and rearrangement in the mouse and human genomes. Proc Natl Acad Sci U S A. 2003 Sep 30;100(20):11484-9. PMID: 14500911; PMC: PMC208784

Schwartz S, Kent WJ, Smit A, Zhang Z, Baertsch R, Hardison RC, Haussler D, Miller W. Human-mouse alignments with BLASTZ. Genome Res. 2003 Jan;13(1):103-7. PMID: 12529312; PMC: PMC430961