Exploring genetic diversity and structure of Acacia senegal (L.) Willd. to improve its conservation in Niger

Abstract

The genetic diversity of African forest resources is poorly documented while it can be the basis for adapting these resources to climatic variations. This study aimed to characterize the genetic diversity of the Acacia senegal (L.) Willd in its natural range in Niger. 252 individuals from 10 populations of the species, across three gum basins were analyzed with 9 nuclear microsatellite markers. Genetic diversity indexes are high in all the populations studied: number of allele (Na) varies from 4.00 to 5.44; allele richness (R) varies from 3.42 to 4.49; observed heterozygosity (Ho) and expected heterozygosity (He) range from 0.44 to 0.56 and from 0.46 to 0.63, respectively. The values of differentiation index (Fst) per pair of population range from 0.0057 to 0.110 and 20% of these values are not significant indicating a low differentiation between populations. In addition, molecular variance analysis shows that 93% of total variation is within populations. Through Bayesian model, a structure of population into three groups is observed. These results could form the basis for building sustainable management and conservation strategies of genetic resources of A. senegal in Niger.

Climate change will disproportionally affect the most genetically diverse lineages of a widespread African tree species

“…Range-wide heterozygosity levels obtained from this study ( H e = 0.56) are very similar to levels obtained in previous analyses of microsatellite markers of S. senegal populations in western Africa ( H e = 0.54–0.56) 44 but slightly lower than in the eastern range in Kenya ( H e = 0.617) 6 . This may be due to the use of slightly different sets of markers and differences in sample size.…”

“…Overall, population differentiation was high at both chloroplast (Ф PT = 0.733) and nuclear markers ( F ST = 0.287) and higher than previous values for regional assessments 39 , 44 , 47 due to differentiation among phylogroups at the range level, in particular as we included the Namib region in our analysis (Table 1 , Supplementary Table 2 ). However, within regions, we found similar values of differentiation as previously reported for western (0.145) 39 and eastern (0.045) 47 Africa respectively.…”

Development of an SSR-based DNA fingerprinting method for black wattle (Acacia mearnsii De Wild)

“…The mean genetic diversity value observed in A. mearnsii (H e = 0.524) in this study was much higher than the study conducted on A. longifolia in Portugal (H e = 0.190) (Vicente et al 2018) using SSRs. However, the value is more comparable with a study of A. senegal (H e = 0.519) (Djibo et al 2017), A. auriculiformis (H e = 0.60) (Son et al 2016) and A. mangium (H e = 0.56) (Son et al 2016) using SSRs. The inbreeding coefficient (F IS ) measures the deviation of heterozygosity from expected values under the assumptions of Hardy Weinberg.…”