 "We don't ask anyone to accept Williamson's ideas – only to evaluate them on the basis of science and scholarship, not knee-jerk prejudice", said Margulis.Williamson's hypothesis was rebutted in response papers in the same journal issue by the biologists Michael W. Hart and Richard K. Grosberg and Gonzalo Giribet (Curator of Invertebrates in the Museum of Comparative Zoology at Harvard University) and later by Arnab De and Rituparna Bose.Even though the latter authors rectified some of the signs considered by Williamson as molecular evidence of an ancestral hybridogenesis, they recommended a laboratory hybridisation study between an onychophore and a cockroach, as proposed by Williamson.