Inferences of evolutionary history of a widely distributed mangrove species, Bruguiera gymnorrhiza, in the Indo‐West Pacific region

Abstract

Inference of genetic structure and demographic history is fundamental issue in evolutionary biology. We examined the levels and patterns of genetic variation of a widespread mangrove species in the Indo-West Pacific region, Bruguiera gymnorrhiza, using ten nuclear gene regions. Genetic variation of individual populations covering its distribution range was low, but as the entire species it was comparable to other plant species. Genetic differentiation among the investigated populations was high. They could be divided into two genetic clusters: the West and East clusters of the Malay Peninsula. Our results indicated that these two genetic clusters derived from their ancestral population whose effective size of which was much larger compared to the two extant clusters. The point estimate of speciation time between B. gymnorrhiza and Bruguiera sexangula was two times older than that of divergence time between the two clusters. Migration from the West cluster to the East cluster was much higher than the opposite direction but both estimated migration rates were low. The past Sundaland and/or the present Malay Peninsula are likely to prevent gene flow between the West and East clusters and function as a geographical or land barrier.

Ancient Geographical Barriers Drive Differentiation among Sonneratia caseolaris Populations and Recent Divergence from S. lanceolata

“…During glacial periods, global sea levels dropped and exposed the bulk of the shallow seabed in the SCS, forming temporary land bridges connecting mainland Asia with the three Sunda Islands (Sumatra, Borneo and Java; Voris, 2000; Sathiamurthy and Voris, 2006). This landmass likely acted as a strong physical barrier halting sea-drifted gene flow between the SCS and the Indian Ocean populations of S. caseolaris during Pleistocene, consistent with the differentiation mechanism suggested for other mangrove species (Ge and Sun, 2001; Liao et al, 2007; Huang et al, 2008; Urashi et al, 2013; Wee et al, 2015) and numerous marine organisms (Barber et al, 2000; Nelson et al, 2000; Crandall et al, 2008; DeBoer et al, 2008; Froukh and Kochzius, 2008). …”

“…Although the majority of species are shared between the two regions (Hogarth, 1999, 2001), there are 7–9 species exclusively distributed in Australasia, while 11 are exclusive to Indo-Malesia (Duke et al, 1998). Genetic breaks between populations from the two regions have been observed in many mangrove species, such as Lumnitzera littorea (Su et al, 2007), Bruguiera gymnorrhiza (Urashi et al, 2013), and Rhizophora mucronata (Wee et al, 2015). Understanding the linkage between intra- and inter-species genetic diversity on one hand, and historical geological events on the other hand should provide important insights into the evolutionary mechanisms of biodiversity generation in mangrove plants.…”

Effects of Pleistocene sea-level fluctuations on mangrove population dynamics: a lesson from Sonneratia alba

“…5c; Table 2). Similar paucity of intra-species genetic diversity was also observed in another mangrove species, Bruguiera gymnorrhiza [33]. …”

“…3a; Additional file 5). A similar genetic break between these two areas has also been observed in other mangrove species, including B. gymnorrhiza [33] and R. stylosa [24]. Furthermore, the species composition of mangroves in the Indo-Malesia region is distinct from the Australasia region.…”

Genetic Structure and Population Demographic History of a Widespread Mangrove Plant Xylocarpus granatum J. Koenig across the Indo-West Pacific Region

“…The Malay Peninsula has been reported as a clear land barrier for several mangrove species, such as B. gymnorhiza [8,9,14] and Ceriops tagal [7]. This land barrier emerged in this region during the LGM, and has been routinely evoked as an explanation for the genetic structure of mangrove plants across the Malay Peninsula [57].…”