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Good species despite massive hybridization: genetic research on the contact zone between the watersnakes Nerodia sipedon and N. fasciata in the Carolinas, USA
Author(s) -
MEBERT K.
Publication year - 2008
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1111/j.1365-294x.2008.03725.x
Subject(s) - biology , hybrid , contact zone , evolutionary biology , hybrid zone , interspecific competition , ecology , interspecific hybridization , zoology , genetics , genetic variation , gene flow , botany , gene , ethnology , history
Genomic markers generated with the amplified fragment length polymorphism method revealed extensive, panmictic‐like hybridization along the narrow contact zone between the water snakes Nerodia sipedon and Nerodia fasciata in the Carolinas, USA. However, asymmetric distributions of diagnostic markers between both species and low frequencies of backcrossed hybrids with a high value of interspecific mixture infer selection against certain genotypes. This is consistent with a pronounced genetic and morphological preponderance of N. fasciata characters in the hybrid zone. Despite massive hybridization within the contact zone, the existence of nearly fixed genetic markers and the potential inferiority of certain hybrid genotypes support the species status of the two taxa and corroborate known, but nondiagnostic differences in morphology and ecology. This study stretches the applicability of species concepts to cases, where the genetic compatibility between two closely related species is very high, yet, they still evolve and persist as independent entities.