Record Details
Genetic diversity of populations of Astragalus oniciformis using inter-simple sequence repeat (ISSR) markers
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Genetic diversity of populations of Astragalus oniciformis using inter-simple sequence repeat (ISSR) markers |
| Names |
Alexander, J. Andrew
(creator) Liston, Aaron I. (advisor) |
| Date Issued | 2001-05-14 (iso8601) |
| Note | Graduation date: 2002 |
| Abstract | Astragalus oniciformis Barneby is a xerophyte of the sagebrush deserts of central Idaho. It is a narrow endemic of the upper Snake River Plains where it inhabits stabilized, aeolian sand deposits over Quaternary basalt flows. The objective of this study was to determine the levels and distribution of genetic differentiation within and among populations of Astragalus oniciformis. Fifteen individuals from each of eight populations, chosen from throughout the range of the species, were selected for their accessibility, density of individuals, and large population size. Two disjunct eastern populations selected for this study have been separated from the continuous western populations for 3600 years by an eight-mile wide, inhospitable lava flow. Inter-simple sequence repeats (ISSR) were chosen as the marker to assess genetic differentiation. Two primers were selected that yielded 40 loci, all of which were polymorphic in A. oniciformis. In an analysis of molecular variance (AMOVA), 88.69 percent of the variation was significantly attributed to variation within populations. The differentiation between the two disjunct populations and the western populations was insignificant. High gene flow (Nm=3.91-3.93) and a low percent deviation from Hardy-Weinberg equilibrium due to population subdivision (G[subscript st]=0.113-0.1134) were found among populations of A. oniciformis. These results suggest that current threats to this species, ranging from plant community changes due to changing fire patterns, habitat alteration from livestock grazing, and habitat loss from agricultural development have not yet affected the genetic diversity of this species. Preservation of the numerous, large populations and the high gene flow will help insure that the levels of genetic diversity found in Astragalus oniciformis will not decrease. |
| Genre | Thesis/Dissertation |
| Topic | Picabo milkvetch -- Snake River Plain (Idaho and Or.) -- Genetics |
| Identifier | http://hdl.handle.net/1957/30006 |
