Session Gallery
What is a Session?
A session is a specific set of track combinations, that can include custom tracks allowing snapshots of browser activities. Multiple sessions may be saved for future reference, for comparing different data sets, or for sharing with your colleagues. Follow these links to learn how to create and share sessions.
What is the Session Gallery?
The Session Gallery is a collection of track views that help highlight viewing different topics in the browser. The sessions in the Session Gallery were created in the browser and then saved to a local file, which was then uploaded to an online location. This allows creating a single link, such as http://genome.ucsc.edu/cgi-bin/hgTracks?hgS_doLoadUrl=submit&hgS_loadUrlName=U, where U is the URL of the session file, e.g. http://www.mysite.edu/~me/mySession.txt, enabling users to maintain external control of the content file for easy update.
Session Gallery
DNA/Codon View
Examples of Stop Codons in the hg19 Assembly

The above session helps illustrate the display of how one gene can have different transcripts with different stop codons, displayed in red in the browser.
Premature Stop in the hg18 Reference Assembly

A premature stop codon was found in the hg18 reference genome and about half of
people of European descent. The UCSC Genes track was forced to skip the codon.
Clicking the top highlighted rs4940595 in the Human Genome Diversity Project SNP Population Allele Frequencies track will display the world frequency image regarding this variant. In the more recent hg38 reference genome this area displays differently. Link to region in hg38 for comparison.
Examples of Start Codons in the hg19 Assembly

The above session helps illustrate the display of how one gene can have different transcripts with different start codons, displayed in green in the browser. Here is an example session displaying a start codon on the reverse strand. By clicking the "reverse" button below the browser one can flip the view.
Examples of Split Codons in the hg19 Assembly

The above session helps illustrate how a codon can be split between splice sites. By clicking the little double-headed arrow on the left of one of the transcripts one can see the other part of the codon. Note that there are different AAs (G or R) depending on the different splicing upstream for different isoforms.
Examples of Different Codon Numbering in the hg19 Assembly

The above session helps illustrate the how same region in an exon can have different codon numbering reflecting different isoforms and that it is important to use caution when reading codon numbers in the literature. Here is an additional view of the region zoomed out 300x to display the alternate splicing.
Evolution
Examples of Codon Wobble in the hg19 Assembly

The above session helps illustrate how codon wobble in bases diverges through evolution when the amino acid is the same (note the conservation score graph). There is a conservation of function through evolution with V > I > F amino acids and K > R substitutions. Here is an additional example session displaying wobble.
Examples of Evolution in the hg19 Assembly

This session shows alignments of three species (Chimp, Gorilla, and Orangutan) against chr2 in hg19 and how the same sequences are found in two separate chromosomes in the other species.

Zooming in above to a region of human chr2 you can see heterochromatin around a vestigial
centromere which has not evolved away yet. By using the top blue menu bar under View to
select "In Other Genomes (Convert)" you can select the Chimp assembly panTro4 and
see that these coordinates in hg19 (chr2:126,645,017-138,651,416) coincide with the
centromere in the Chimp chr2B:
SNPs and Disease
Examples of SNP coloring and ABO variant details in the hg19 Assembly

The above session helps illustrate how SNPs are color coded regarding whether they represent a nonsense, missense, or frameshift variation. These SNPs are around the ABO gene and represent blood group variation.
By clicking into the gene track for one of the isoforms of the ABO gene one can see additional variant
details by clicking the "Gene Alleles" link to jump down to the "Common Gene Haplotype
Alleles" section and mouseover highlighted variant amino acids to see changes in nucleotide and
AA sequences.
Examples of OMIM allelic variants in the hg19 Assembly

The top track in the above session displays OMIM allelic variants. By clicking the items one can learn the details and find additional links to the allelic variants in the Online Mendelian Inheritance in Man (OMIM) database.
In the above and this zoomed in session you can mouseover OMIM variants to access details such as OMIM Allelic Variant 136350.0021 in the far right to see "PRO366LEU,rs121909641:HYPOGONADOTROPIC HYPOGONADISM 2 WITH ANOSMIA, SUSCEPTIBILITY TO" to learn additional information about each variant.Examples of CAG Repeats in Huntingtin in the hg19 Assembly

The above session uses the Short Match Track to display matches of "cagcagcagcagcagcag" repeats in a polyglutamine region (Note Qs) of the gene HTT, Huntingtin, linked to Huntington's disease.
Examples of Segmental Duplications in the hg19 Assembly

The above session uses the Segmental Dups to display regions detected as putative genomic duplications within the golden path and shows X-linked colorblindness as a recombination hotspot in the opsin region where genes encode for light absorbing visual pigments.
Another example featuring the Segmental Dups track is the 15q11 Prader-Willi region in which same-chromosome duplications lead to gain and loss of copies and a rare genetic disorder when some genes are deleted or unexpressed.
Expression/Regulation: TFBS/RNA-seq/ChIP-seq
Microarray Probset data in the hg19 Assembly

The above session uses the Microarray Probesets track to display Affymetrix, Agilent, and Illumina probe information.
View ENCODE data (2003 - 2012) in the UCSC Genome Browser

The above session highlights some key integrated track data from the ENCODE project including GENCODE gene sets, Transcription Levels by RNA-seq, H3K27Ac histone mark, DNaseI Hypersensitivity, ChIP-seq Transcription Factor binding sites, and Genome Segmentations.
Mailing List Support
Example of displaying repeats in the hg19 Assembly

A user was interested in an intron region of the gene PHKB where a repeat element for AluY was given. The user could not find the Alu repeat, and the response was to aid the user in turning on the RepeatMasker track where information on repeats, such as the AluY element desired, is contained.
Troubleshooting Common Problems
Please see the How to share your UCSC screenthoughts blog entry for a thorough discussion about sessions.
Most new users make the mistake of sharing a URL of the current view to others for collaboration. This can lead to many problems as each URL is given a unique identifier called a "hgsid" that allows users to continue actively manipulating their data across different platforms (FireFox,Chrome,IE). The person one shares the link with will be interpreted as the same user and will have the power to continue manipulating the original shared content.
When you want to share information in the browser in a more permanent fashion you should create a session and share the resulting URL. From the Session page, copy the link that says "Browser" with a right-click. The URL should look something like the following: http://genome.ucsc.edu/cgi-bin/hgTracks?hgS_doOtherUser=submit&hgS_otherUserName=sessionGallery&hgS_otherUserSessionName=hg19_watsonKriekIn the above case a user name was created called sessionGallery and a session was created called hg19_watsonKriek. This more stable link is the best way to share information, with the only further improvement being to locally download your session file and then remotely share it from your own private collection in an internet accessible location using the hgS_loadUrlName= option. For example seen in this link: http://genome.ucsc.edu/cgi-bin/hgTracks?hgS_doLoadUrl=submit&hgS_loadUrlName=http://genome.ucsc.edu/goldenPath/help/examples/sessions/encodeDemonstration