Abstract Detail

Tropical Biology Section

Schnabel, Andrew [1], Otero-Arnaiz, Adriana [1], Oudghiri, Salima [1], Nichols, Penny [1].

Molecular approaches to the study of historical and contemporary seed gene flow in Acacia brevispica (Mimosoideae: Leguminosae) from East Africa.

We have initiated a two-pronged approach to the study of seed gene flow in Acacia brevispica, a widespread, shrubby species of eastern and southern Africa. First, we are investigating variation in noncoding regions of chloroplast DNA (trnL intron and trnL-trnF spacer) to help understand historical patterns of seed gene flow within the species as a whole. Since chloroplast DNA is maternally inherited, and thus is not found in pollen, geographic patterns of cpDNA variation among populations should reflect historical patterns of migration by seed dispersal. Based on restriction maps developed from approximately 1100 bp of sequence data, we have begun to screen populations for restriction site variation. To date, no variation has been observed within the first few populations sampled, all of which have come from a small area in and around Mpala Research Centre (MRC) in Kenya. More wide-scale sampling of populations is currently underway. Second, we are testing the possibility of using parentage analysis of seed coat genotypes from dispersed seeds and seedlings to study contemporary patterns of seed gene flow within mapped populations at MRC, where A. brevispica fruits are dispersed by elephants and other large mammalian herbivores. Because a seed coat develops from maternal integument tissue, its genotype should be the same as the genotype of its maternal tree. To date, we have successfully extracted DNA from seed coats using both Qiagen kits and more traditional CTAB methods. Preliminary genotyping suggests that seed coat genotypes match the genotypes of the maternal plant from which the seeds were collected. We are currently collecting dispersed seeds and seed coats in the field at MRC to test further the feasibility of this approach.

1 - Indiana University South Bend, Biological Sciences, 1700 Mishawaka Ave., South Bend, Indiana, 46615, USA

Keywords:
Acacia
gene flow
seed coat
Chloroplast DNA
microsatellite DNA.

Presentation Type: Poster
Session: 33-114
Location: Salon C, D & E - Gov Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 12:30 PM
Abstract ID:470