Vivipary with precocious seedlings in mangrove plants was thought to be a hindrance to long-range dispersal. To examine the extent of seedling dispersal across oceans, we investigated the phylogeny and genetic structure among East Asiatic populations of Kandelia candel based on organelle DNAs. In total, three, 28 and seven haplotypes of the chloroplast DNA (cpDNA) atpB-rbcL spacer, cpDNA trnL-trnF spacer, and mitochondrial DNA (mtDNA) internal transcribed spacer (ITS) were identified, respectively, from 202 individuals. Three data sets suggested consistent phylogenies recovering two differentiated lineages corresponding to geographical regions, i.e. northern South-China-Sea + East-China-Sea region and southern South-China-Sea region (Sarawak). Phylogenetically, the Sarawak population was closely related to the Ranong population of western Peninsula Malaysia instead of other South-China-Sea populations, indicating its possible origin from the Indian Ocean Rim. No geographical subdivision was detected within the northern geographical region. An analysis of molecular variance (AMOVA) revealed low levels of genetic differentiation between and within mainland and island populations (phiCT = 0.015, phiSC = 0.037), indicating conspicuous long-distance seedling dispersal across oceans. Significant linkage disequilibrium excluded the possibility of recurrent homoplasious mutations as the major force causing phylogenetic discrepancy between mtDNA and the trnL-trnF spacer within the northern region. Instead, relative ages of alleles contributed to non-random chlorotype-mitotype associations and tree inconsistency. Widespread distribution and random associations (chi2 = 0.822, P = 0.189) of eight hypothetical ancestral cytotypes indicated the panmixis of populations of the northern geographical region as a whole. In contrast, rare and recently evolved alleles were restricted to marginal populations, revealing some preferential directional migration.
The South East Asian Nutrition Surveys (SEANUTS) were conducted in 2010/2011 in Indonesia, Malaysia, Thailand and Vietnam in country representative samples totalling 16,744 children aged 0.5 to 12 years. Information on socio-demographic and behavioural variables was collected using questionnaires and anthropometric variables were measured. In a sub-sample of 2016 children, serum 25-hydroxy-vitamin D (25(OH)D) was determined. Data were analysed using SPSS complex sample with weight factors to report population representative data. Children were categorized as deficient (<25 nmol/L), insufficient (<50 nmol/L), inadequate (<75 nmol/L) or desirable (>=75 nmol/L). In Malaysia and Thailand, urban children had lower 25(OH)D than rural children. In all countries, except Vietnam, boys had higher 25(OH)D levels and older children had lower 25(OH)D. Regional differences after correcting for age, sex and area of residence were seen in all countries. In Thailand and Malaysia, 25(OH)D status was associated with religion. The percentage of children with adequate 25(OH)D (>=75 nmol/L) ranged from as low as 5% (Indonesia) to 20% (Vietnam). Vitamin D insufficiency (<50 nmol/L) was noted in 40 to 50% of children in all countries. Logistic regression showed that girls, urban area, region within the country and religion significantly increased the odds for being vitamin D insufficient. The high prevalence of vitamin D insufficiency in the (sub) tropical SEANUTS countries suggests a need for tailored approach to successfully combat this problem. Promoting active outdoor livestyle with safe sunlight exposure along with food-based strategies to improve vitamin D intake can be feasible options.