Code changes are completed to include the bigGenePred file type as well in the supported file types for UCSC and added logic to parse them. Written test case for the same. Updated code is available at the branch: https://bitbucket.org/jaya-sravani/integrated-genome-browser/branch/IGBF-3658.
To test:

1. Download https://bitbucket.org/jaya-sravani/integrated-genome-browser/downloads/ installer or clone this branch to local https://bitbucket.org/jaya-sravani/integrated-genome-browser/branch/IGBF-3658 and start the application.
2. Select a particular genome. (note: hg38 has data for this track)
3. Select any bigGenePred track (dataset) type.
4. Click on the load data button either from the top right corner or in the data management table.
5. Check whether the data is loaded correctly and the peak is visible.

Tested using UCSC table browser file knownGene.bed.gz compared to the knownGene from UCSC REST API in IGB. Also compared data to the UCSC REST API result from: https://api.genome.ucsc.edu/getData/track?genome=hg38&track=knownGene&chrom=chr1&start=62901&end=63934

The only issue I see is that the exon blocks seem to be missing data, such as block number and name. If the entire gene model is selected the information lines up with knownGene.bed.gz but if just an exon is selected data are missing.

BigGenePred is being treated as genePred, both under the hood get converted into UcscGeneSym in the case of a bed file it gets converted to UcscBedSym. Both the syms have different implementations, UcscBedSym has more info in it whereas the UcscGeneSym doesn't, leading to fewer fields in the Selection info tab. After discussing with Nowlan Freese, we decided to change the underlying Syms for both genePred and bigGenePred to use UcscBedSym. Changes are done according to that and the latest code is available at the branch: https://bitbucket.org/jaya-sravani/integrated-genome-browser/branch/IGBF-3658. Nowlan Freese, Please review and let me know if there are any issues.

Changes look good, ready for pull request.

Raised a Pull request https://bitbucket.org/lorainelab/integrated-genome-browser/pull-requests/994. Please review and let me know if there are any issues.

PR is merged and installers are built and deployed to the Bioviz Web site as "early access".

Tested using the main branch from loraine lab. Used the same testing strategy outlined in my previous comment.

Files loaded in IGB appeared identical and matched with the REST call.

Closing ticket.