title: Extensive Natural Hybridization Between Two Geckos, Gekko tawaensis and Gekko japonicus (Reptilia: Squamata), Throughout Their Broad Sympatric Area.
abstract: The status of natural hybridization between the two Japanese geckos, Gekko tawaensis and Gekko japonicus, was surveyed by use of 15 diagnostic allozyme loci. Of 438 specimens examined, 9 were identified as F(l), 1 was a first backcross with G. japonicus, and 15 were identified as more successive generations. Hybridizations were detected at 7 of the 15 localities interspersed throughout a broad sympatric area of the two species, forming a mosaic hybrid zone. A comparison of species-hybrid composition between 2-year samples from a single locality and a 5-year interval showed no evidence for progressive introgression or establishment of a hybrid swarm, despite constant emergences of F(l) hybrids. Nonprevalence of the hybrid genotypes was also indicated by the analysis using hybrid index scores for all other localities examined. These results suggest that strong selection acts against hybrid genotypes. Morphological features of hybrid individuals were also provided.
authors.affiliation: Tropical Biosphere Research Center, University of the Ryukyus, Nishihara, Okinawa, 903-0213, Japan. gecko@zoo.zool.kyoto-u.ac.jp
authors.forename: Mamoru
authors.initials: M
authors.lastname: Toda
authors.forename: Sumio
authors.initials: S
authors.lastname: Okada
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hikida
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Ota
mesh_terms: D000483:Alleles; D000818:Animals; D002678:Chimera / Q000033:anatomy & histology* / Q000235:genetics*; D004798:Enzymes / Q000235:genetics; D005787:Gene Frequency; D005838:Genotype; D006579:Heterozygote; D006824:Hybridization, Genetic; D007564:Japan; D008116:Lizards / Q000033:anatomy & histology* / Q000235:genetics*
chemical_list: D004798:Enzymes