Eucyclops roseus 복합종에 존재하는 2개 종에 대한 분자생물학적 동정

초록

As copepod is most abundant zooplankton in the marine and freshwater aquatic ecosystem in the views of species diversity and bio-mass, accurate identification of these species are vitally important for monitoring environmental fluctuations and estimating biodiversity. Zooplanktonic crustaceans, like copepods are difficult to identification because of the microscopic size of distinguishing morphology. Furthermore, of late years, it was cleared that majority of copepods composes 'complex' or 'polytypic species'. We studies the genetic structure of populations of the copepods Eucyclps roseus. A 600-bp segment of the cytochrome c oxidase subunit Ⅰ(COⅠ) mitochondrial gene was sequenced in 5 specimens from different localities (Euc. sp., Euc01002, Euc01006, Euc01007, Euc01008) and was sequenced in 1 specimen from one locality(Ect01001). In our analysis, these 5 specimens are devided to two groups, population 1 and population 2. 3 specimens (Euc. sp., Euc01006, Euc01008) are included in population 1 and 2 specimens (Euc01002, Euc01007) are included in population 2. Ectocyclops phaleratus(Koch), Ect01001 was used for phylogenetic tree outgroup. In population 1, the number of polymorphic sites are 11 and the nucleotide diversity, Pi(1) is 0.01178. In population 2, the number of polymorphic sites are 2 and the nucleotide diversity, Pi(2) is 0.00307. Between populations, the number of polymorphic sites are 137 and the nucleotide diversity, Pi(t) is 0.12458. Also, the NM(the number of migration) is 0.01. This score means that migration accurs very rare. In consequence, the lack of gene flow and the genetic divergence suggest that two different groups of Eucyclops roseus are in fact cryptic species rather than differentiated populations of the same species.