Intraspecific Genetic Variation Among Populations Of Kenyan African Violet, Saintpaulia Rupicola B. L. Burtt: A Molecular Approach

Abstract

Saintpaulia rupicola B. L Burtt (Gesneriaceae) is one of the African Violet species under high threat of extinction from its habitat. It is endemic to coastal Kenya where it occurs in Kilifi and Kwale districts in four distinct populations. The Cha Simba and Mwarakaya populations contain plants that correspond to the typical Saintpaulia rupicola. However, the other two populations. Kacharoroni and Mwache consist of plants which are morphologically different, and which may qualify to be treated as separate species, Saintpaulia sp. nov. In order to design a conservation plan for this species, an insight in the genetic diversity among these populations is required. Furthermore, a study at the molecular level could help to clarify the taxonomic position of Saintpaulia sp. nov. with regard to S. rupicola and other taxa in the genus Saintpaulia. The Internal Transcribed Spacer region (ITS) of the nuclear ribosomal DNA was analyzed as a genetic marker to determine the genetic variation among these populations. DNA sequencing of this region revealed its conserved nature, with only four (0.63 % of the whole region) base substitutions among the four populations. Low genetic distances (between 0.0000 to 0.0048) were. observed among these populations, indicating that the four are closely related, the most closely related being Kacharoroni and Mwache populations (0.0016). Cladistic analysis using Geneworks Release 2.3 and PHYLIP analysis programs generated a total of five phylogenetic trees which cluster Mwarakaya with Cha Simba and Kacharoroni with Mwache.