The example is excellent since while the dna research can be executed in parallel the trials with humans (and animal trials before) do take real calendar time.

The example is excellent since while the dna research can be executed in parallel the trials with humans (and animal trials before) do take real calendar time. And unlike test tubes where breakage is part and parcel of doing stuff breaking human experimental subjects is frowned upon and their involvement is scaled up slowly in stages for ethical reasons.