Codon and Base Coloring for Alignment Tracks

The Genome Browser's codon coloring feature allows users to quickly validate and compare alignment tracks, including mRNAs. To turn on codon coloring, select the desired option from the Color track by codons pull-down menu.

Color Options

genomic codons - codons are labeled and colored according to the genomic sequence
mRNA codons - codons are labeled and colored according to the aligned sequence
nonsynonymous mRNA codons - codons are labeled and colored according to the aligned sequence. Only nonsynonymous codons are labeled. Conservative and non-conservative substitutions are defined using the BLOSUM62 score matrix. Conservative substitutions (yellow) are defined as positive BLOSUM scores, while non-conservative substitutions (red) are defined as negative scores.
mRNA bases - bases are labeled.
different mRNA bases - only those bases that differ from the genomic sequence are labeled and colored.

Color Legend

	Genomic/mRNA codons	Nonsynonymous mRNA codons	mRNA bases/different mRNA bases
red	"*" stop codons	non-conservative codon substitutions	base substitutions
yellow		conservative codon substitutions
cyan	spliced or truncated partial codons	spliced or truncated partial codons
green	start codons incl. methionine
black	"X" truncated codons

Details

The codon reading frame is defined by the GenBank CDS annotation of the aligned sequence. Each codon is colored and labeled in the direction of transcription. A sequence without a CDS will not be colored; these can be non-protein coding RNAs or an mRNA where a CDS annotation was not provided in the original data.

The mRNA bases/different mRNA bases display options are colored and labeled in the direction of the genomic sequence. Note that it is possible to show the base complement, and thus change the base labeling, by clicking the arrow to the left of the base display or by clicking the "reverse" button.

When zoomed out past the base level, the browser will choose one color to represent many bases. The priority of display, from most important to least important, is: different mRNA base/nonsynonymous codon coloring (if enabled), and then alignment coloring (if enabled). The browser will not display genomic/mRNA codon coloring when viewing large regions of the genome. To view labeling, the track must be zoomed to within 3 times the base level.

For information about alignment insertion/deletion display options, click here.

References

Henikoff S and Henikoff JG. Amino acid substitution matrices from protein blocks. PNAS. 1992;89(22):10915-10919.