Browsing by Author "Arctander, Peter"

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    Population Genetic Structure of Savannah Elephants in Kenya: Conservation and Management Implications
    (Journal of heredity, 2008) Okello, John B. A.; Masembe, Charles; Rasmussen, Henrik B.; Wittemyer, George; Omondi, Patrick; Kahindi, Onesmas; Muwanika, Vincent B.; Arctander, Peter; Douglas-Hamilton, Iain; Nyakaana, Silvester; Siegismund, Hans R.
    We investigated population genetic structure and regional differentiation among African savannah elephants in Kenya using mitochondrial and microsatellite markers. We observed mitochondrial DNA (mtDNA) nucleotide diversity of 1.68% and microsatellite variation in terms of average number of alleles, expected and observed heterozygosities in the total study population of 10.20, 0.75, and 0.69, respectively. Hierarchical analysis of molecular variance of mtDNA variation revealed significant differentiation among the 3 geographical regions studied (FCT 5 0.264; P , 0.05) and a relatively lower differentiation among populations within regions (FSC 5 0.218; P , 0.0001). Microsatellite variation significantly differentiated among populations within regions (FSC 5 0.019; P , 0.0001) but not at the regional levels (FCT 5 0.000; P . 0.500). We attribute the high differentiation at the mitochondrial genome to the matrilineal social structure of elephant populations, female natal philopatry, and probably ancient vicariance. Lack of significant regional differentiation at the nuclear loci vis-a-vis strong differences at mtDNA loci between regions is likely the effect of subsequent homogenization through male-mediated gene flow. Our results depicting 3 broad regional mtDNA groups and the observed population genetic differentiation as well as connectivity patterns should be incorporated in the planning of future management activities such as translocations.
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    Population genetic structure of the common warthog (Phacochoerus africanus) in Uganda: evidence for a strong philopatry among warthogs and social structure breakdown in a disturbed population
    (African Journal of Ecology, 2007) Muwanika, Vincent B.; Nyakaana, Silvester; Siegismund, Hans R.; Arctander, Peter
    Fine-scale genetic structure of large mammals is rarely analysed. Yet it is potentially important in estimating gene flow between the now fragmented wildlife habitats and in predicting re-colonization following local extinction events. In this study, we examined the extent to which warthog populations from five localities in Uganda are genetically structured using both mitochondrial control region sequence and microsatellite allele length variation. Four of the localities (Queen Elizabeth, Murchison Falls, Lake Mburo and Kidepo Valley) are national parks with relatively good wildlife protection practices and the other (Luwero), not a protected area, is characterized by a great deal of hunting. In the total sample, significant genetic differentiation was observed at both the mtDNA locus (FST ¼ 0.68; P < 0.001) and the microsatellite loci (FST ¼ 0.14; P < 0.001). Despite the relatively short geographical distances between populations, significant genetic differentiation was observed in all pair-wise population comparisons at the two marker sets (mtDNA FST ¼ 0.21–0.79, P < 0.001; microsatellite FST ¼ 0.074–0.191, P < 0.001). Significant heterozygote deficiency was observed at most loci within protected areas while no significant deviation from Hardy–Weinberg expectation was observed in the unprotected Luwero population. We
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    A recent bottleneck in the warthog and elephant populations of Queen Elizabeth National Park, revealed by a comparative study of four mammalian species in Uganda national parks
    (Animal Conservation, 2003) Muwanika, Vincent B.; Siegismund, Hans R.; Okello, John Bosco A.; Masembe, Charles; Arctander, Peter; Nyakaana, Silvester
    Until 1972, Uganda’s national parks boasted of large numbers of large mammal species. Following the breakdown of law and order between 1972 and 1985, large-scale poaching led to an unprecedented decline in numbers of most large mammals in Uganda’s national parks. However, the extent of decline varied in the different parks across different animal species. We have investigated the genetic effects of these reductions in four mammalian species (the common warthog, African savannah elephant, savannah buffalo and common river hippopotamus) from the three major parks of Uganda using both microsatellite loci (for elephant and warthog populations) and mitochondrial control sequence variation in the warthogs, elephants, buffaloes and hippopotamuses. Queen Elizabeth National Park showed extreme reduction in nucleotide diversity for two species, the common warthog (π = 0.0%) and African elephant (π = 0.4%); no such decrease was found for the two other species, the buffalo (π = 3.7–5.4%) and hippopotamus (π = 1.7–1.9%), in the three parks. Nuclear microsatellite markers on the other hand showed high gene diversity in all populations in the common warthog (mean He 0.66–0.78) and the African savannah elephant (mean He 0.68–0.72). We interpret these results in terms of varying poaching pressure in the different parks, susceptibility of different species to poaching and differences in effective population sizes at the mitochondrial and nuclear loci
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    Three genetically divergent lineages of the Oryx in eastern Africa: Evidence for an ancient introgressive hybridization
    (Conservation Genetics, 2006) Masembe, Charles; Muwanika, Vincent B.; Nyakaana, Silvester; Arctander, Peter; Siegismund, Hans R.
    Phylogeographic and population genetic studies using sequence information are frequently used to infer species boundaries and history; and to assess hybridization and population level processes. In this study, partial mitochondrial DNA (mtDNA) control region (423 bp) and cytochrome b sequences (666 bp) of Oryx beisa sampled from five isolated localities in its entire current range in Africa were analyzed to investigate the extent of genetic variation and differentiation between populations. We observed high nucleotide diversity at the control region in the total sample (6.3%) but within populations, it varied considerably ranging from 1.6% to 8.1%. Population pairwise genetic differentiation was generally significantly high (ranging from FST = 0.15, P<0.01 to FST = 0.54, P<0.001). In the total sample, 29 and 12 haplotypes were observed in the control region and the cytochrome b data sets respectively. For both data sets, the haplotypes cluster into three distinct clades (sequence divergence ranged from 6.0%–12.9% to 0.8%–1.0% for the control region and cytochrome b sequences, respectively) that do not correspond to sampling locations. Two of these clades are found in the same localities (Samburu and Marsabit), which represent the O.beisa beisa subspecies, whereas the last clade represents the fringe-eared oryx (O. beisa callotis). We interpret these findings in terms of an ancient hybridization and introgression between two formerly isolated taxa of Oryx beisa.