Description

These tracks contain cDNA and gene alignments produced by the TransMap cross-species alignment algorithm from human GRCh38.

Display Conventions and Configuration

This track follows the display conventions for PSL alignment tracks.

This track may also be configured to display codon coloring, a feature that allows the user to quickly compare cDNAs against the genomic sequence. For more information about this option, click here. Several types of alignment gap may also be colored; for more information, click here.

Methods

  1. Source transcript annotations were obtained from GRCh38 in the UCSC Genome Browser Database. The GENCODE and RefSeq gene sets are used.
  2. LAST alignment chains are selected depending on the type of track being built:
  3. The pslMap program was used to do a base-level projection of the source transcript alignments via the selected chains to the $organism genome, resulting in pairwise alignments of the source transcripts to the genome.
  4. The resulting alignments were filtered with pslCDnaFilter with a global near-best criteria of 0.5% in finished genomes (human and mouse) and 1.0% in other genomes. Alignments where less than 20% of the transcript mapped were discarded.

To ensure unique identifiers for each alignment, cDNA and gene accessions were made unique by appending a suffix for each location in the source genome and again for each mapped location in the destination genome. The format is: 

   accession.version-srcUniq.destUniq
Where srcUniq is a number added to make each source alignment unique, and destUniq is added to give the subsequent TransMap alignments unique identifiers.

For example, in the cow genome, there are two alignments of mRNA BC149621.1. These are assigned the identifiers BC149621.1-1 and BC149621.1-2. When these are mapped to the human genome, BC149621.1-1 maps to a single location and is given the identifier BC149621.1-1.1. However, BC149621.1-2 maps to two locations, resulting in BC149621.1-2.1 and BC149621.1-2.2. Note that multiple TransMap mappings are usually the result of tandem duplications, where both chains are identified as syntenic.

Data Access

Contact

Mark Diekhans <markd@ucsc.edu>

Credits

This track was produced by Mark Diekhans at UCSC annotations produced by the RefSeq, Ensembl, and GENCODE annotations projects.

References

Siepel A, Diekhans M, Brejová B, Langton L, Stevens M, Comstock CL, Davis C, Ewing B, Oommen S, Lau C et al. Targeted discovery of novel human exons by comparative genomics. Genome Res. 2007 Dec;17(12):1763-73. PMID: 17989246; PMC: PMC2099585

Stanke M, Diekhans M, Baertsch R, Haussler D. Using native and syntenically mapped cDNA alignments to improve de novo gene finding. Bioinformatics. 2008 Mar 1;24(5):637-44. PMID: 18218656

Zhu J, Sanborn JZ, Diekhans M, Lowe CB, Pringle TH, Haussler D. Comparative genomics search for losses of long-established genes on the human lineage. PLoS Comput Biol. 2007 Dec;3(12):e247. PMID: 18085818; PMC: PMC2134963