Genetic and morphological evidence of hybridization between <Emphasis Type="Italic">Nematalosa japonica</Emphasis> and <Emphasis Type="Italic">N. come</Emphasis> (Clupeiformes: Clupeidae) off Okinawa Island,Ryukyu Archipelago,Japan |
| |
| Authors: | Hideyuki Imai Fumi Kashiwagi Jin-Hua Cheng Tzyy-Ing Chen Katsunori Tachihara Tetsuo Yoshino |
| |
| Institution: | (1) Faculty of Science, University of the Ryukyus, Nishihara Okinawa, 903-0213, Japan;(2) Tungkang Biotechnology Research Center, Taiwan Fisheries Research Institute, Pingtung, 928, Taiwan;(3) Present address: Marketing Division, Uoichi Co., Ltd, Osaka Osaka, 553-8555, Japan |
| |
| Abstract: | Two morphologically similar species of gizzard shad, Nematalosa japonica Regan and N. come (Richardson), sympatrically distributed off Okinawa Island, Japan, were examined using an allozyme locus (SOD*) and two nuclear polymerase chain reaction (PCR)-based DNA markers (ITS-1 and CaM), which provided diagnostic identification of each species. In addition, a multiplex PCR-based mitochondrial DNA (mtDNA)
marker (16S) was used to characterize the distribution of mtDNA haplotypes among specimens. The species composition of sympatric
and allopatric population samples from Tungkang, southern Taiwan, to Okinawa and the Shikoku Islands, Japan, were also examined.
Gizzard shad with hybrid genotypes were detected in three populations from Okinawa Island, with hybrid frequency ranging from
1 to 67%. A backcross level of 2% was detected in the dominant hybrid frequencies of one population sample only. Morphological
examination of hybrids showed intermediate forms, with hybrid indices of three meristic characters falling between those of
the parental species (range 39–53; mean 45). Although principal component analysis showed differences between N. japonica and N. come based on the first principal component scores, hybrids were difficult to identify. Accordingly, satisfactory identification
of species and hybrids could be achieved only using genetic tools. We also discuss the cause of hybridization and its relationship
with recently conducted reclamation on Okinawa Island. |
| |
| Keywords: | Gizzard shad Natural hybrid Nematalosa come Nematalosa japonica Species identification |
| 本文献已被 SpringerLink 等数据库收录！ |
|
