Have you given a look to the Ensembl Genome browser?
Just write the name/ID of the gene, and it will take you to a result page like this. In this example, i've done it for gorilla BRCA2, and in there you get all the isoforms and its length, for this gene (isoforms are given with this kind of identifier ENSZZZTXXXXXXXXXX, with "T" standing for "transcript", "Z" describing the species, and "Xs" is the ID).
If you are familiar with the Ensemble Compara API, you can do it programatically through it... :)
Hope this could help!
modified 5.3 years ago
5.3 years ago by
Peixe • 500