I am an evolutionary biologist who studies the origin and evolution of the genetic code (i.e. that table found in the back cover of every textbook and primer of modern biology):

Why are there twenty amino acids in the standard code?
Why do we see these particular 20?
Why does GGG code for Glycine rather than for Tryptophan?
Why does Tryptophan get only 1 codon whereas Arginine gets 6?
How on earth is it possible that the genetic code changes in many twigs on the tree of life (how can you change the very rules of reading your own genes, and still pass this on to future generations?)

I am also a bioinformatician who studies the subtle and largely overlooked influences that the standard genetic code exerts over "regular" evolution of protein-coding genes. This involves studies of codon usage and synthetic gene design, of alignment algorithms and scoring matrices.