Genetic Variation in Some Natural Populations of Prunus africana (Hook.F) Kalkman (Rosaceae) from Ethiopia as Revealed by Random Amplified Polymorphic DNA (RAPD)
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Date
2006-12
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Addis Ababa University
Abstract
Prunus africana (Hook.f.) Kalkman (Rosaceae) is a multipurpose Afromontane tree species which is
threatened by over-exploitation and habitat destruction in a number of African countries, including
Ethiopia. As a result, there is a growing concern of conservation and sustainable utilization of the species.
Understanding of the patterns of variation within and among populations of the species is a prerequisite
for devising optimum management strategies for its conservation and sustainable utilization. Here,
random amplified polymorphic DNA (RAPD) analysis was used to assess the extent of genetic variation
and the partition of within and among six populations of P. africana sampled from six different
geographical regions of Ethiopia. From the total number of amplified loci, 82.3% revealed to be
polymorphic for the whole data set. The within population diversity estimated by Nei’s gene diversity
estimates ranged from 0.307 for Tepi to 0.150 to Bulki, with a mean of 0.234. Genetic differentiation
between populations was estimated with Nei’s GST (0.262) and AMOVA based FST (0.257; P<0.00001),
which appears to be slightly higher than the values obtained from various RAPD based studies on
outcrossing and long-lived species. Both GST and AMOVA derived FST revealed higher proportion of
variation within populations (74%) relative to the amount of variation among populations (26%). Nei’s
genetic distance estimated between pair of populations ranged from 0.061 (between Agere Mariam and
Lepisi) to 0.213 (between Chilimo and Agere Mariam), with the mean of 0.147 among the six populations.
Genetic relationships among the populations examined by UPGMA cluster analysis based on Nei’s
genetic distance separated the six populations into two primary clusters which some what reflects their
geographical locations: one composed of Agere Mariam, Lepisi, Bulki and Tepi, and the other composed
of Bedele and Chilimo. The Bulki and Tepi populations were further separated from the Agere Mariam
and Lepisi populations within the first cluster. The results of the present study suggest that the Tepi,
Lepisi and Chilimo populations have higher genetic variability and need to be given priority for both in
situ and ex situ conservation. Those of Agere Mariam, Bedele and Bulki populations should also be
conserved as they may have some unique genes.
Key words: Prunus africana, RAPD, population, conservation, Ethiopia
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Keywords
Prunus africana, RAPD, population, conservation, Ethiopia