How many human species?

Analysis of the draft sequence of the Neanderthal genome (published in 2010) revealed that modern humans owe  1-4% of our DNA to our archaic ancestors. Furthermore, analysis of genomic data from the Denisovan fossils (published in December 2010) shows that modern Melanesians owe up to 6% of their genomes to Denisovans. If the biological definition of species is:

(1) The lowest taxonomic rank, and the most basic unit or category of biological classification.(2) An individual belonging to a group of organisms (or the entire group itself) having common characteristics and (usually) are capable of mating with one another

then, these data suggest Neandertals, Denisovans, and humans are all one species?