Abstract Detail

Genetics Section

Otero-Arnaiz, Adriana [1], Marshall, Michelle [1], Harsh, Joe [2], Schnabel, Andrew [1].

From clones to populations: Genetic structure of Acacia brevispica in East Africa.

Acacia brevispica is widespread in Northeast, East and South Africa, where it grows as small trees or clustered shrubs. These clusters may be the result of the proliferation of ramets of the same genet following herbivory by large mammals such as elephants. We have begun analyzing the genetic diversity of Acacia brevispica at different spatial scales in Laikipia, Kenya. We used 5 microsatellite loci, representing 75 alleles, to investigate clonal growth and limited gene flow through pollen or seeds as causes of spatial genetic structure in a plot of 80 x 100 m. We identified the clones from the expected likelihood of the 5-locus genotypes and excluded ramet pairs before characterizing the spatial genetic structure of mapped individuals. Additionally, we used 7 microsatellite loci and 8 allozyme loci to describe the genetic structure of 5 local populations. We found spatial genetic structure (P < 0.001) for distances lower than 40 m, indicating isolation by distance caused by a limitated gene flow at local scale. However, genetic differentiation between populations ((F_ST = 0.03 ± 0.01 s.e.) may result more from local adaptation than from isolation by distance.