Blind Source Separation
Blind source separation (BSS) is a process to recover a set of unobserved source signals from their linear mixtures with unknown coefficients. Very little is assumed to be known about the sources, except that they are mutually independent and that at most one of them is Gaussian.
non-negative matrix factorization and other derived algorithms.
For instance, check this link for recent work.
Introductory review material is here.
Several tools and algorithms can be found through this link.
Recently there´s been interest also in the systems biology domain of problems.
An example of application area is here.
Here is a review on the role of signal processing in genomics and proteomics.