Population genetic structure of three tree species in the mangrove genus Ceriops (Rhizophoraceae) from the Indo West Pacific

Abstract

Ceriops is a viviparous mangrove with widespread species Ceriops decandra and C. tagal, and an endemic species C. australis. Genetic diversity of the three species was screened in 30 populations collected from 23 locations in the Indo West Pacific (IWP) using Inter-simple sequence repeats (ISSR) and sequences of partial nuclear gene (G3pdh) and chloroplast DNA (trnV-trnM). At the species level, the total gene diversity (Ht) revealed by ISSRs was 0.270, 0.118, and 0.089 in C. decandra, C. tagal, and C. australis, respectively. A total of six haplotypes of G3pdh and five haplotypes of trnV-trnM were recognized among the three species. Only C. decandra was detected containing more than one haplotype from each sequence data set (four G3pdh haplotypes and three trnV-trnM haplotypes). At the population level, genetic diversity of Ceriops was relatively low inferred from ISSRs (He = 0.028, 0.023, and 0.053 in C. decandra, C. tagal, and C. australis, respectively). No haplotype diversity within population was detected from any of the three species. Cluster analysis based on ISSRs identified three major geographical groups in correspond to the East Indian Ocean (EIO), South China Sea (SCS), and North Australia (NA) in both C. decandra and C. tagal. The cladogram from DNA sequences also detected the same three geographical groups in C. decandra. Analysis of molecular variance (AMOVA) revealed that most of the total variation was accounted for by differentiation between the three major geographical regions of both C. decandra and C. tagal. The significant genetic structure may result from the geological events in these regions during the recent Pleistocene glaciations. This study also provided insights into the phylogenetics of Ceriops.

Levels and patterns of DNA variation in two sympatric mangrove species, Rhizophora apiculata and R. mucronata from Thailand

“…This is likely to be consistent with the land barrier hypothesis of the Malay Peninsula, in which the Malay Peninsula prevents gene flow between mangrove species occurring along the coasts of the Pacific and Indian Oceans leading to population differentiation between western and eastern populations of the Malay Peninsula (Duke et al, 2002). Results reported for the Ceriops species are also consistent with this hypothesis (Huang et al, 2008;Liao et al, 2007). In contrast, in R. mucronata the pattern of population differentiation of the nuclear genes was inconsistent with that of the cpDNA regions.…”

“…Patterns of haplotype distribution of chloroplast DNA (cpDNA) regions in Ceriops tagal (Huang et al, 2008;Liao et al, 2007), a species of the Rhizophoraceae family, is consistent with the so-called land barrier hypothesis of the Malay Peninsula, in which the past and/or present land barrier of the Malay Peninsula is expected to prevent gene flow between mangrove species occurring along the coasts of the Pacific and Indian Oceans leading to population differentiation between western and eastern populations of the Malay Peninsula (Duke et al, 2002). The levels of polymorphism of cpDNA regions in C. tagal were unexpectedly high: however, it is not clear whether those cpDNA regions are also highly variable in other mangrove species.…”

Vicariance and Oceanic Barriers Drive Contemporary Genetic Structure of Widespread Mangrove Species Sonneratia alba J. Sm in the Indo-West Pacific

“…Populations from Australia were observed to be genetically close to populations from the South China Sea in Ceriops spp. [5], to populations from the Indian Ocean in R. mucronata [44], and to populations in the Northwest Pacific Ocean in R. apiculata [44]. The presence of this major genetic break in S. alba (and R. stylosa) may be explained by a periodic land barrier during glacial periods in the past 250,000 years, which lies between Australia and New Guinea, across the present Timor Sea, Arafura Sea and Torres Strait [45].…”

“…The genetic divide was thought to be caused by the geographic separation between populations in the Pacific Ocean from those in the Indian ocean that was imposed by the land mass during past glacial maxima [4]. In addition, mangroves from the IWP also exhibited phylogeographic congruency across species, whereby populations were genetically differentiated according to three subregions: the EIO, SCS and Northern Australia (NA), thus suggesting limited gene flow across these subregions [4][5][6]. These phylogeographic congruencies in co-distributed mangroves not only enabled the identification of geographic factors (e.g., land barriers) that shaped the genetic structure, but also provided insights into past dynamics of mangrove forest cover.…”

Eight new species of marine dolichopodid flies of Thinophilus Wahlberg, 1844 (Diptera: Dolichopodidae) from peninsular Thailand

“…The species of the mangroves along the coast of the Chinese mainland differ from those of Taiwan (Becker 1922), Northeast Borneo (Parent 1935) and those of the southern part of the South China Sea, as shown in the present study. Differences in faunal composition between the Gulf of Thailand and the Andaman Sea is more trivial, since the composition of the mangrove flora on either side of the Thai-Malay Peninsula has been proven to be different (Ge & Sun 2001;Huang et al 2008;Minobe et al 2009;Liao et al 2009). We do not yet have information on the insect fauna in general.…”