Genetic Structure of the Red-spotted Tokay Gecko, Gekko gecko(Linnaeus, 1758)(Squamata: Gekkonidae) from Mainland Southeast Asia

This study was performed to explore the genetic diversity and genetic structure of red-spotted tokay geckos(Gekko gecko) from 23 different geographical areas in Thailand, Lao PDR and Cambodia. The mitochondrial tRNAGln/tRNA-Met/partial NADH dehydrogenase subunit 2 from 166 specimens was amplified and sequenced. A total of 54 different haplotypes were found. Highly significant genetic differences occurred between populations from different localities. The haplotype network revealed six major haplogroups(G1 to G6) belonging to different clades(clade A–E). Clade D and clade E were newly observed in this study. Haplogroup G4(clade D) was a sympatric population with haplogroup G1(clade B). The populations from northern Thailand were divided into two distinct haplogroups separated by mountain range. Genetic structure and genetic differentiation of the tokay in Southeast Asia was related to the geographical region sampled, spatial distance and natural barriers. Our results indicate that red-spotted tokay geckos from mainland Southeast Asia are cryptically diverse. Morphological comparisons, in addition to an intensive genetic investigation covering the whole species range, are needed to clarify the systematic and population structure of this species group.

Genetic Differentiation of the Forest Crested Lizards,Calotes emma alticristatus Schmidt,1925 and C.emma emma Gray,1845(Squamata:Agamidae)Relating to Climate Zones in Thailand

In Thailand,the forest crested lizard,Calotes emma consists of two subspecies,C.emma alticristatus Schmidt,1925 and C.emma emma Gray,1845.This study was performed to determine the genetic diversity and differentiation of C.emma from 16 different localities throughout Thailand.A total of 116 samples were analyzed using the mitochondrial cytochrome c oxidase subunit 1(CO1).Of these,65 and 51 of C.e.alticristatus and C.e.emma were classified into 23(N1-N23)and 21(S1-S21)haplotypes,respectively.There was no shared haplotype between subspecies or between different populations within each subspecies.These haplotypes were classified into four(north-A to north-D)and three(south-A to south-C)haplogroups of C.e aliristaus and C.e.emma,respectively.Phylogenetic analyses retrieved four lineages(classified asⅠtoⅣ).LineagesⅠandⅡcontained the four haplogroups of C.e.alicristatus,whereas lineageⅡandⅣcontained three haplogroups of C.e.emma.These two subspecies live separately in different climate zones,ie.C.e.alticristatus is found in an equatorial winter dry climate,whereas C.e.emma inha bits areas with an equa torial monsoonal clima te.

Multilocus enzyme electrophoresis analysis of Echinostoma revolutum and Echinostoma malayanum(Trematoda:Echinostomatidae) isolated from Khon Kaen Province,Thailand

Objective:To explore the genetic variation and differentiation of 2 echinostomes from genus Echinostoma,i.e.Echinostoma revolutum(E.revolution) and Echinostoma malayanum(E. malayanum) from Khon Kaen Province,Thailand.Methods:These parasites were compared at 22 enzymes encoding a presumptive 30 loci by using multilocus enzyme electrophoresis (MEE) technique.Results:Twenty-two loci can be used as diagnostic markers to differentiate these 2 species.E.revolutum and E.malayanum had fixed genetic differences at 70%of loci, whereas both species had fixed genetic differences from the liver fluke,Opisthorchis viverrini at 91%of loci.Intraspecific variation within a population of E.revolutum was observed at 5 polymorphic loci.Conclusions:MEE is a powerful technique to investigate genetic variation and differentiation of E.revolutum and E.malayanum.

Genetic variation and phylogenetic relationship of Hypoderaeum conoideum(Bloch, 1782) Dietz, 1909(Trematoda: Echinostomatidae) inferred from nuclear and mitochondrial DNA sequences

Objective:To explore genetic variations of Hypoderaeum conoideum collected from domestic ducks from 12 different localities in Thailand and Lao PDR,as well as their phylogenetic relationship with American and European isolates.Methods:The nucleotide sequences of their nuclear ribosomal DNA(ITS),mitochondrial cytochrome c oxidase subunit 1(CO1),and NADH dehydrogenase subunit 1(ND1)were used to analyze genetic diversity indices.Results:We found relatively high levels of nucleotide polymorphism in ND1(4.02%),whereas moderate and low levels were observed in CO1(2.11%)and ITS(0.96%),respectively.Based on these polymorphisms,the 20 ND1,12 CO1,and 18 ITS haplotypes were classified,and several common haplotypes were observed in all samples.At least three major lineages,namely American,European and Asian lineages,have been classified by phylogenetic analyses based on ND1 sequences.Conclusions:Our report demonstrates that the ND1 gene is the most suitable genetic marker to explore genetic variation and phylogenetic relationship of Hypoderaeum conoideum.However,a combination of all loci for ND1,CO1 and ITS would be of great value toward further genetic investigation of this endemic worldwide parasite.Thus,comprehensive molecular genetic analyses of Hypoderaeum conoideum from its worldwide distribution is needed to further understanding of the evolutionary and systematic relationships of this parasite.

Genetic Diversity and Population Structure of the Oriental Garden Lizard,Calotes versicolor Daudin,1802(Squamata:Agamidae)along the Mekong River in Thailand and Lao PDR

Calotes versicolor Daudin,1802,is geographically widespread along the Mekong River basin.The Mekong River is play important role as a significant natural barrier to several terrestrial animals living on different sides.This study aims to analyze the genetic diversity and population structure of C.versicolor populations collected from different sides of Mekong River using mitochondrial cytochrome c oxidase subunit 1(CO1)sequences.We obtained sequences of 200 individuals from 18 sampling localities from left and right sides of the Mekong River in Lao PDR and Thailand respectively.Overall,91 haplotypes were detected,which reflect high levels of genetic diversity in this species at the study areas.Haplotype network and phylogenetic analyses revealed that there were six major lineages(lineage C–lineage H)of C.versicolor populations within the Mekong River,whereas lineages A and B have previously been found from China and Vietnam.The genetic distance among C.versicolor was significantly related to spatial distance,however,the Mekong River had no significant effect on genetic distance.Our findings,together with previous studies,suggests that C.versicolor in Asia is a species complex with other cryptic lineages being likely but there is a need for further exploration.Thus,comprehensive genetic,biological and ecological studies of C.versicolor should be conducted throughout its entire distribution range.