slavery produced some fine specimines..........
No it did not. First off, The Phenotype does not determine the Genotype. Also, the gene pool was too varied and constantly changing to select for certain alleles, and the alleles that you "think" were selected for, would be impossible to discern and isolate given the short generation of slavery. The population was not isolated enough, thus the gene pool was not isolated to select for "favorable" alleles. nor were enough generations birthed to effect any kind of genetic change, couple that with an incredibly diverse population.
Never repeat this myth again.