sci-biology/
ucsc-genome-browser

The UCSC genome browser suite, also known as Jim Kent's library and GoldenPath

http://genome.ucsc.edu/

There are no pull requests

You think something is missing here?
Start with filling a new pull requests.

If you also like to help the Gentoo project, you can consider sending a Pull Request via GitHub.
Before doing so, you might want to take a look at the wiki page.