Genetic diversity of the narrow endemic Astragalus oniciformis (Fabaceae)

Abstract

Astragalus oniciformis Barneby is a narrow endemic xerophyte of the upper Snake River Plain of central Idaho, USA, where it inhabits stabilized, aeolian sand deposits and previously burned, sandy sites over Quaternary basalt flows. The objective of this study was to determine the levels and distribution of genetic differentiation within and among populations of A. oniciformis. Fifteen individuals from each of eight populations, chosen from throughout the range of the species, were selected based on accessibility, density of individuals, and large population size. Inter-simple sequence repeats were chosen as the marker to assess genetic differentiation. The two primers selected yielded 40 polymorphic loci in A. oniciformis. In an analysis of molecular variance, 88.69% of the variation was significantly attributed to variation within populations. High gene flow (N(m) = 3.91-3.93; SD = 0.01) and a low percentage deviation from Hardy-Weinberg equilibrium due to population subdivision (G(ST) = 0.113-0.1134; SD = 0.0002) were found among sampled populations. These results suggest that current threats to this species, including changing fire patterns and habitat loss from grazing disturbance, have not yet affected the genetic diversity of this species. Preservation of large populations and smaller, intervening, dispersed patches will help preserve the genetic integrity and the genetic diversity found in A. oniciformis.

Differences in the growth of beach Pandan, Pandanus odoratissimus, between tropical (Java) and subtropical (southern Japan) zones

“…In the present study, we used inter-simple sequence repeat (ISSR) analysis to examine the genetic differentiation within P. odoratissimus populations. This sensitive, reproducible, and cost-efficient method can be used to i n v e s t i g a t e t h e g e n e t i c s t r u c t u r e a n d g e n e t i c differentiation within and among populations of limited or widespread species (Alexander et al 2004, Deshpande et al 2001, Ge et al 2005, Hu et al 2008, McCauley and Ballard 2002, Rossi et al 2009, Xiao et al 2004. ISSR was also reported as a useful method for analyzing species that lacked available sequence information, because this m e t h o d d o e s n o t r e q u i r e p r i o r D N A s e q u e n c e information before amplification (Hu et al 2008).…”

Genetic differentiation in Aspidosperma polyneuron (Apocynaceae) over a short geographic distance as assessed by AFLP markers

“…Amplified fragments of between 50 to 1000 bp were used to create a presence/absence matrix. markers may prove to be problematic (Zhivotovsky, 1999;Alexander et al, 2004). The possibility of statistical deviations could be eliminated through highly polymorphic data (Krauss, 2000).…”

Construction of a molecular identification profile of new varieties of Nierembergia linariae folia by anchored microsatellites

“…This technique was successfully applied to the study of Astragalus oniciformi populations (Alexander et al 2004), Penstemon sp (Wolfe et al 1998) and in taxonomic studies of Vigna (Ajibade et al 2000). In ornamental species ISSRs have been used in Jacaranda sp (Pérez de la Torre et al 2003;Escandón et al 2005a), Nierembergia (Escandón et al 2005b), Pandorea sp (Jain et al 1999) and Chrysantemum (Wolff et al 1995).…”