Both of these are good development languages, particularly for large projects. However, for bioinformatics or other science/academic projects, they have neither the wide range of libraries and ease of writing quick scripts that python has, nor the speed of something like C.

I think that for most academic uses, ease of development is really important. Remember, most of these people don't have CS backgrounds, which makes python a good choice because it's easy to learn and doesn't require much setup. It's main drawback is that it's slow, but this doesn't matter in many cases. When I was in grad school, I'd use a small dataset to try to figure out the best algorithm and then if I had to leave my computer running overnight to run on a larger dataset, it usually wasn't a big deal.

On the other hand, sometimes you just need something really fast. In that case, C is your darling.

Java/C# make lots of tradeoffs on both sides, which works well for software developers but not necessarily researchers (who don't have to worry about code being maintainable).