People who take a "layer cake" view of federalism believe that

the ss was the main organization responsible for the genocidal murder of around six million people of european ethnic minorities, essentially jews, in the holocaust. the members of all its branches committed war crimes and crimes against humanity during the second world war (1939-1945). likewise, the ss were involved in commercial enterprises and exploited the inmates of the concentration camps as slave laborers.

the tortures and assassinations committed by the ss were the result of an ideology developed long before the armed conflict, this ideology was based on the racial supremacy of the germans over the rest.

genetics is the study of how dna works, the methodologies defining the new recent technologies allow scientist to have a panoramic view of the entire dna landscape, especially how genomes interact with their environment, including off course, factors outside their organisms.

thus is very possible the existence of both scenarios, where populations of isolated individuals have different genetic traits, and share traits related to genetic mutation, due rats can easily travel overseas using human transport channels. so scientists could get a vast number of data, including human interaction, evolution of rodents, health development, spread of infections, development of new organisms, how genomes evolve in different environments and so on.