Genetic Diversity of Dalbergia monticola (Fabaceae) an Endangered Tree Species in the Fragmented Oriental Forest of Madagascar

Abstract

There is an urgent need to maintain and restore a broad genetic base for the management of Dalbergia monticola, a very economically important but endangered tree species in Madagascar. Random amplified polymorphism DNAs (RAPDs) and chloroplast microsatellite markers were used to quantify the genetic variation and to analyse the geographic distribution of diversity. Ten locations covering most of the natural range were sampled. Sixty-three RAPD polymorphic and 15 monomorphic loci were obtained from 122 individuals. Genetic diversity was low and very close among populations and regions. The unrooted neighbour-joining tree exhibited 4 groups, representing 6% (p = 0.000) of the total variation. The greater part of the variance, 81%, was observed within populations. A Mantel test suggested that genetic distances between populations were weakly correlated with geographic distances (R = 0.46, p = 0.12). The three chloroplast microsatellite primers assayed on 100 individuals gave 13 chlorotypes. Most of the populations showed 2 or 3 haplotypes. Haplotype diversity for the total population was equal to He Cp = 0.83 and ranged from 0.00 to 0.80 among the populations. The unrooted neighbour-joining tree exhibited 4 groups corresponding to the four regions representing 80% (p = 0.0000) of the total variation. Genetic diversity varies with regions, the north and south being less variable. Chlorotype distribution, the phylogenetic tree and historical information suggest that putative refugias in the centre-north region originating from the early Holocene could explain the pattern of variation observed today. By combining the results obtained at nuclear and organellar loci, a strategy of conservation based on evolutionarily significant units is proposed.

Determination of the Population Structure of Fig Genotypes from Algeria and Turkey Using Inter Primer Binding Site-Retrotransposon and Simple Sequence Repeat Markers

“…Furthermore, fig domestication in all the Mediterranean regions has been influenced by human activities [44] [50]. Thus, the fragmentation of tree resources can significantly increase this type of activity [51]. In the current research, a weak genetic structure was observed probably due to the circulating these genotypes.…”

Plant population dynamics on oceanic islands during the Late Quaternary climate changes: genetic evidence from a tree species (Coffea mauritiana) in Reunion Island

“…The LGM period was also associated with rainfall variations in equatorial East Africa, but the peak glacial drought overlapped only partly with the LGM proper (Gasse et al ., ; Verschuren et al ., ). At a local scale, paleo‐records from Mauritius and Madagascar also supported drier conditions during the LGM (Gasse & Van Campo, ; Andrianoelina et al ., ; Van Der Plas et al ., ). However, the results from demographic inference in C. mauritiana did not reveal an impact of the wet/dry spells that alternated during the Holocene in SWIO and East Africa (Gasse & Van Campo, ; Gasse et al ., ; Verschuren et al ., ), suggesting that climate changes in the Holocene period differentially impacted Reunion Island forest compared with the climatic changes of the LGM.…”

Phylogeography of Eastern Polynesian sandalwood (Santalum insulare), an endangered tree species from the Pacific: a study based on chloroplast microsatellites

“…In S. insulare , very low values, smaller than H e = 0.25, have been estimated for some islands, but this parameter is high for others (Tahuata, Moorea), and does not show a specific pattern compared with other tree species such as Vitellaria paradoxa or Dalbergia monticola exhibiting similar values at the sub‐population level (Fontaine et al. , 2004; Andrianoelina et al. , 2005).…”