Potential drivers of samango monkey (Cercopithecus albogularis) population subdivision in a highly fragmented mountain landscape in northern South Africa.

Forests affected by fragmentation are at risk of losing their primate populations over the long term. The impact of fragmentation on primate populations has been studied in several places in Africa, Asia and South America; however, there has been no discernible pattern of how primates react to forest disturbance and fragmentation. In fragmented habitats, the local extinction probability of a species increases due to a decrease in patch area and an increase in genetic isolation. Here we used microsatellite markers and mitochondrial DNA sequences to investigate how habitat fragmentation impacts on the genetic diversity and structure of a samango monkey population inhabiting forest patches in the Soutpansberg mountain range of northern South Africa. We sampled four local populations across the length of the mountain range and an additional outlying population from the Great Escarpment to the south. Our results indicate that local populations along the mountain range were historically more connected and less distinct than at present. In more recent times, a lack of contemporary gene flow is leading to a more pronounced genetic structure, causing population subdivision across the mountain and likely isolating the Soutpansberg population from the escarpment population to the south. Based on our results, we suggest that natural and anthropogenic fragmentation are driving population genetic differentiation, and that the matrix surrounding forests and their suitability for samango monkey utilisation play a role at the local scale. The degree of genetic isolation found for samango monkey populations in our study raises concerns about the long-term viability of populations across the mountain range.

Population Genomics Reveals Incipient Speciation, Introgression, and Adaptation in the African Mona Monkey (Cercopithecus mona).

Guenons (tribe Cercopithecini) are the most widely distributed nonhuman primate in the tropical forest belt of Africa and show considerable phenotypic, taxonomic, and ecological diversity. However, genomic information for most species within this group is still lacking. Here, we present a high-quality de novo genome (total 2.90 Gb, contig N50 equal to 22.7 Mb) of the mona monkey (Cercopithecus mona), together with genome resequencing data of 13 individuals sampled across Nigeria. Our results showed differentiation between populations from East and West of the Niger River ∼84 ka and potential ancient introgression in the East population from other mona group species. The PTPRK, FRAS1, BNC2, and EDN3 genes related to pigmentation displayed signals of introgression in the East population. Genomic scans suggest that immunity genes such as AKT3 and IL13 (possibly involved in simian immunodeficiency virus defense), and G6PD, a gene involved in malaria resistance, are under positive natural selection. Our study gives insights into differentiation, natural selection, and introgression in guenons.

The Genome of the Endangered Dryas Monkey Provides New Insights into the Evolutionary History of the Vervets.

Genomic data can be a powerful tool for inferring ecology, behavior, and conservation needs of highly elusive species, particularly, when other sources of information are hard to come by. Here, we focus on the Dryas monkey (Cercopithecus dryas), an endangered primate endemic to the Congo Basin with cryptic behavior and possibly <250 remaining adult individuals. Using whole-genome sequencing data, we show that the Dryas monkey represents a sister lineage to the vervets (Chlorocebus sp.) and has diverged from them ∼1.4 Ma with additional bidirectional gene flow ∼750,000-∼500,000 years ago that has likely involved the crossing of the Congo River. Together with evidence of gene flow across the Congo River in bonobos and okapis, our results suggest that the fluvial topology of the Congo River might have been more dynamic than previously recognized. Despite the presence of several homozygous loss-of-function mutations in genes associated with sperm mobility and immunity, we find high genetic diversity and low levels of inbreeding and genetic load in the studied Dryas monkey individual. This suggests that the current population carries sufficient genetic variability for long-term survival and might be larger than currently recognized. We thus provide an example of how genomic data can directly improve our understanding of highly elusive species.

Haemogram and Serum Biochemical Values of Four Indigenous Species of Monkeys in South West Nigeria.

Haematological and serum biochemical values are useful guides and biomarkers in health and diseases for reaching a diagnosis, estimating disease prognosis and monitoring treatment progress, in mammals. Reference ranges for some parameters differ among species of mammals and between sexes within a species. There is dearth of information on standard reference value for blood parameters for Nigerian indigenous monkeys. Whole blood and serum samples obtained from 50 apparently healthy adult monkeys in both captivity and from the wild in southwest Nigeria were subjected to haematology and serum biochemistry to obtain preliminary reference values for haematological and serum biochemical analytes for Cercocebus sebaeus (Green monkey), Cercopithecus mona (Mona monkey), Erythrocebus patas (Patas monkey) and Papio anubis (Anubis baboon). Numerical data were summarized as mean and standard deviation and subjected to statistical analysis; Student t test and analysis of variance, to compare values of blood parameters obtained between species and gender. A p-value less than 0.05 was considered significant. The hematocrit of male animals were significantly higher than that of females (P=0.01) in all the 4 species studied but there was no significant difference in other blood parameters such as total white blood cell and the differential counts, platelet count, serum aspartate transferase, alanine transferase, alkaline phosphatase, total plasma protein, albumin, and globulin concentrations between the sexes. Generally, there was no significant difference between total white blood cell and the differential counts, hematocrit, red cell count, haemoglobin concentration, platelet count, serum aspartate transferase, alanine transferase, alkaline phosphatase, total plasma protein, albumin, and globulin concentrations among the monkey species.

Population genetic structure and evolutionary history of Bale monkeys (Chlorocebus djamdjamensis) in the southern Ethiopian Highlands.

BACKGROUND: Species with a restricted geographic distribution, and highly specialized habitat and dietary requirements, are particularly vulnerable to extinction. The Bale monkey (Chlorocebus djamdjamensis) is a little-known arboreal, bamboo-specialist primate endemic to the southern Ethiopian Highlands. While most Bale monkeys inhabit montane forests dominated by bamboo, some occupy forest fragments where bamboo is much less abundant. We used mitochondrial DNA (mtDNA) sequences to analyse the genetic structure and evolutionary history of Bale monkeys covering the majority of their remaining distribution range. We analysed 119 faecal samples from their two main habitats, continuous forest (CF) and fragmented forests (FF), and sequenced 735 bp of the hypervariable region I (HVI) of the control region. We added 12 orthologous sequences from congeneric vervets (C. pygerythrus) and grivets (C. aethiops) as well as animals identified as hybrids, previously collected in southern Ethiopia. RESULTS: We found strong genetic differentiation (with no shared mtDNA haplotypes) between Bale monkey populations from CF and FF. Phylogenetic analyses revealed two distinct and highly diverged clades: a Bale monkey clade containing only Bale monkeys from CF and a green monkey clade where Bale monkeys from FF cluster with grivets and vervets. Analyses of demographic history revealed that Bale monkey populations (CF and FF) have had stable population sizes over an extended period, but have all recently experienced population declines. CONCLUSIONS: The pronounced genetic structure and deep mtDNA divergence between Bale monkey populations inhabiting CF and FF are likely to be the results of hybridization and introgression of the FF population with parapatric Chlorocebus species, in contrast to the CF population, which was most likely not impacted by hybridization. Hybridization in the FF population was probably enhanced by an alteration of the bamboo forest habitat towards a more open woodland habitat, which enabled the parapatric Chlorocebus species to invade the Bale monkey's range and introgress the FF population. We therefore propose that the CF and FF Bale monkey populations should be managed as separate units when developing conservation strategies for this threatened species.

The Targeted Sequencing of Alpha Satellite DNA in Cercopithecus pogonias Provides New Insight Into the Diversity and Dynamics of Centromeric Repeats in Old World Monkeys.

Alpha satellite is the major repeated DNA element of primate centromeres. Specific evolutionary mechanisms have led to a great diversity of sequence families with peculiar genomic organization and distribution, which have till now been studied mostly in great apes. Using high throughput sequencing of alpha satellite monomers obtained by enzymatic digestion followed by computational and cytogenetic analysis, we compare here the diversity and genomic distribution of alpha satellite DNA in two related Old World monkey species, Cercopithecus pogonias and Cercopithecus solatus, which are known to have diverged about 7 Ma. Two main families of monomers, called C1 and C2, are found in both species. A detailed analysis of our data sets revealed the existence of numerous subfamilies within the centromeric C1 family. Although the most abundant subfamily is conserved between both species, our fluorescence in situ hybridization (FISH) experiments clearly show that some subfamilies are specific for each species and that their distribution is restricted to a subset of chromosomes, thereby pointing to the existence of recurrent amplification/homogenization events. The pericentromeric C2 family is very abundant on the short arm of all acrocentric chromosomes in both species, pointing to specific mechanisms that lead to this distribution. Results obtained using two different restriction enzymes are fully consistent with a predominant monomeric organization of alpha satellite DNA that coexists with higher order organization patterns in the C. pogonias genome. Our study suggests a high dynamics of alpha satellite DNA in Cercopithecini, with recurrent apparition of new sequence variants and interchromosomal sequence transfer.

Genetic assessment of an isolated endemic Samango monkey (Cercopithecus albogularis labiatus) population in the Amathole Mountains, Eastern Cape Province, South Africa.

The endemic Samango monkey subspecies (Cercopithecus albogularis labiatus) inhabits small discontinuous Afromontane forest patches in the Eastern Cape, KwaZulu-Natal midlands and southern Mpumalanga Provinces in South Africa. The subspecies is affected by restricted migration between forest patches which may impact on gene flow resulting in inbreeding and possible localized extinction. Current consensus, based on habitat quality, is that C. a. labiatus can be considered as endangered as the small forest patches they inhabit may not be large enough to sustain them. The aim of this study was to conduct a molecular genetic investigation to determine if the observed isolation has affected the genetic variability of the subspecies. A total of 65 Samango monkeys (including juveniles, subadults and adults) were sampled from two localities within the Hogsback area in the Amathole Mountains. Nuclear and mitochondrial DNA variation was assessed using 17 microsatellite markers and by sequencing the hypervariable 1 region (HVR1). Microsatellite data generated was used to determine population structure, genetic diversity and the extent of inbreeding. Sequences of the HVR1 were used to infer individual origins, haplotype sharing and haplotype diversity. No negative genetic factors associated with isolation such as inbreeding were detected in the two groups and gene flow between groups can be regarded as fairly high primarily as a result of male migration. This was in contrast to the low nuclear genetic diversity observed (H o = 0.45). A further reduction in heterozygosity may lead to inbreeding and reduced offspring fitness. Translocations and establishment of habitat corridors between forest patches are some of the recommendations that have emerged from this study which will increase long-term population viability of the subspecies.

X Chromosome Introgression and Recombination in the cephus Group of Cercopithecus Monkeys.

A representative of Cercopithecus erythrotis was surveyed at a 9.3-kb region of the X chromosome. The data were compared against homologous sequences of closely related Cercopithecus monkeys including C. cephus, a species recently shown to have 2 polymorphic X-chromosomal lineages. Direct sequence comparisons and subsequent phylogenetic analyses revealed that synapomorphies in the first 4.3 kb cluster C. erythrotis with one C. cephus lineage, while synapomorphies in the latter 5.0 kb join it with the second C. cephus lineage. This pattern very likely reflects an ancestral episode of introgression from C. cephus into C. erythrotis followed by a recombination event. Similar groups of synapomorphies occur at different phylogenetic depths within the C. erythrotis/C. cephus/C. ascanius radiation and reveal new details in the evolutionary history of this 3-species clade.

Diversity and distribution of alpha satellite DNA in the genome of an Old World monkey: Cercopithecus solatus.

BACKGROUND: Alpha satellite is the major repeated DNA element of primate centromeres. Evolution of these tandemly repeated sequences has led to the existence of numerous families of monomers exhibiting specific organizational patterns. The limited amount of information available in non-human primates is a restriction to the understanding of the evolutionary dynamics of alpha satellite DNA. RESULTS: We carried out the targeted high-throughput sequencing of alpha satellite monomers and dimers from the Cercopithecus solatus genome, an Old World monkey from the Cercopithecini tribe. Computational approaches were used to infer the existence of sequence families and to study how these families are organized with respect to each other. While previous studies had suggested that alpha satellites in Old World monkeys were poorly diversified, our analysis provides evidence for the existence of at least four distinct families of sequences within the studied species and of higher order organizational patterns. Fluorescence in situ hybridization using oligonucleotide probes that are able to target each family in a specific way showed that the different families had distinct distributions on chromosomes and were not homogeneously distributed between chromosomes. CONCLUSIONS: Our new approach provides an unprecedented and comprehensive view of the diversity and organization of alpha satellites in a species outside the hominoid group. We consider these data with respect to previously known alpha satellite families and to potential mechanisms for satellite DNA evolution. Applying this approach to other species will open new perspectives regarding the integration of satellite DNA into comparative genomic and cytogenetic studies.

The efficacy of sex-chromosomal markers in studies of Cercopithecus hybridization: Discovery of a captive hybrid and applications in wild populations.

We demonstrate the utility of previously described molecular methods for identifying hybrid Cercopithecus monkeys. Using phylogenetic analyses and DNA sequence comparisons at X-chromosomal and Y-chromosomal loci, we have identified a hybrid animal in the Cheyenne Mountain Zoo (USA)--an identification that was not known a priori but was later confirmed by review of zoo records. The molecular techniques employed here are of great use to studies of the genus Cercopithecus because, unlike most mammals, these monkeys frequently form polyspecific associations, and recent deforestation is likely to have driven otherwise low-level hybridization to higher frequencies which may reduce the fitness of threatened populations. Y-chromosomal markers are especially informative because they provide working hypotheses for (1) the primary mechanism of hybridization (i.e., species A males × species B females) and, by extension; (2) the major direction of gene flow.

New insights into samango monkey speciation in South Africa.

The samango monkey is South Africa's only exclusively forest dwelling primate and represents the southernmost extent of the range of arboreal guenons in Africa. The main threats to South Africa's forests and thus to the samango are linked to increasing land-use pressure and increasing demands for forest resources, resulting in deforestation, degradation and further fragmentation of irreplaceable habitats. The species belongs to the highly polytypic Cercopithecus nictitans group which is sometimes divided into two species C. mitis and C. albogularis. The number of subspecies of C. albogularis is also under debate and is based only on differences in pelage colouration and thus far no genetic research has been undertaken on South African samango monkey populations. In this study we aim to further clarify the number of samango monkey subspecies, as well as their respective distributions in South Africa by combining molecular, morphometric and pelage data. Overall, our study provides the most comprehensive view to date into the taxonomic description of samango monkeys in South Africa. Our data supports the identification of three distinct genetic entities namely; C. a. labiatus, C. a. erythrarchus and C. a. schwarzi and argues for separate conservation management of the distinct genetic entities defined by this study.

Seven novel MHC class I alleles identified in Cercopithecus mitis.

We report here the identification of three Cemi-A and four Cemi-B novel alleles of Cercopithecus mitis.

Lesula: a new species of Cercopithecus monkey endemic to the Democratic Republic of Congo and implications for conservation of Congo's central basin.

In June 2007, a previously undescribed monkey known locally as "lesula" was found in the forests of the middle Lomami Basin in central Democratic Republic of Congo (DRC). We describe this new species as Cercopithecus lomamiensis sp. nov., and provide data on its distribution, morphology, genetics, ecology and behavior. C. lomamiensis is restricted to the lowland rain forests of central DRC between the middle Lomami and the upper Tshuapa Rivers. Morphological and molecular data confirm that C. lomamiensis is distinct from its nearest congener, C. hamlyni, from which it is separated geographically by both the Congo (Lualaba) and the Lomami Rivers. C. lomamiensis, like C. hamlyni, is semi-terrestrial with a diet containing terrestrial herbaceous vegetation. The discovery of C. lomamiensis highlights the biogeographic significance and importance for conservation of central Congo's interfluvial TL2 region, defined from the upper Tshuapa River through the Lomami Basin to the Congo (Lualaba) River. The TL2 region has been found to contain a high diversity of anthropoid primates including three forms, in addition to C. lomamiensis, that are endemic to the area. We recommend the common name, lesula, for this new species, as it is the vernacular name used over most of its known range.

Cebus paraguayanus and Cebus nigritus (Primates, Platyrrhini): a comparative genomic hybridization analysis.

Primate genomes show a great karyological variability while the DNA content variation is scarce. The biggest genome size occurs in Cercophitecus cephus (Catarrhini, Cercophitecidae) with 5.26 pg whereas the smallest one is described for Callicebus torquatus (Platyrrhini, Callithricidae) with 2.26 pg. Over the last 20 years different authors have been studying the Platyrrhini genomes on a chromosomal level. Among them, Cebus (Cebidae) being considered the most ancestral and conserved karyotype in relation to human karyotype has been extensively studied. Cebus genome sizes range from 3.40 to 3.98 pg. The species that inhabit Argentina, where they reach the most southern natural distribution, Cebus paraguayanus (CPA) and Cebus nigritus (CNI), have been extensively studied with classical cytogenetic comparisons focusing on banding pattern behavior. In the present study we performed comparative genomic hybridization (CGH) between these two closely related species with the aim of going a step further in the dissection of Cebus genomes. CGH evidenced that the DNA imbalances between them involved different genome regions, i.e. preferentially repetitive DNA in CPA and coding or very disperse DNA in CNI. Particularly, CNI showed species-specific DNA in more than 9 chromosomal pairs with a red/green (r/g) ratio ranging from 1.7 to 4, meaning that CNI presents at least twice as much DNA than CPA in those chromosomal segments. CPA showed species-specific DNA in the telomeric region of at least 3 chromosomal pairs with an r/g ratio of 0.5. They also showed a DNA gain in the chromosomal pairs with extracentromeric heterochromatin. Our findings modify the widespread idea of considering the heterochromatin proportion as the only difference between CPA and CNI. In Cebus then, the diversification process could be mediated by little changes in DNA content accompanied by a euchromatin-heterochromatin interaction although maintaining a minimum proportion like the one observed in CNI.

Cross-amplified polymorphic microsatellites for Campbell's monkey.

Population genetic analyses are of considerable importance for conservation strategies to protect endangered primates. We tested microsatellites of human origin with an aim to understand the genetic diversity of a West African forest guenon, Campbell's monkey, Cercopithecus campbelli. Twelve markers amplified successfully, were polymorphic and were inherited in a Mendelian fashion in a group of 4 individuals kept in captivity. These 12 markers were further amplified from 35 faecal samples collected in Taï National Park. These samples proved to originate from 18 free-ranging monkeys and showed that the 12 markers we developed for this species are polymorphic and suitable for future population genetic and parentage analyses.

Female social relationships in a captive group of Campbell's monkeys (Cercopithecus campbelli campbelli).

A study group of Campbell's monkeys (Cercopithecus c. campbelli) provided data on affiliative and agonistic relationships between females. Over a period of two years (involving 111 hr), we conducted observations of a captive group which had a composition similar to wild groups. We were able to identify a monitor-adjust social system with frequent affiliative interactions, directed gazing and avoidances rather than aggressive acts. We described long-term differentiated affiliative bonds: adult females interacting more often with some group mates than others, especially if they were relatives. Interactions between matrilines concerned essentially play and young adult females. We found a significant linear hierarchy of dominance with rare reversals and a stable intermatriline dominance. In contrast to other single-male groups, our adult male was socially integrated into the group although this may have been because of the housing conditions. Comparisons with the social organization of other captive and wild guenon groups are discussed.

Behavioral development of captive male hybrid cercopithecine monkeys.

In this study, we compare the behavioral development of captive male vervet monkeys (Chlorocebus pygerythrus) and Sykes' monkeys (Cercopithecus albogularis) to male hybrids of these species. Focal animal sampling sessions were conducted on the study subjects from birth to 90 months of age. Behavioral categories (affiliative, approach, play, sexual, tension, aggressive) were plotted for each species and the hybrids; curves were fitted using polynomial regression and were evaluated with the Wilcoxon signed ranks test. With the exception of play behaviors, the male C. pygerythrus x C. albogularis hybrids modeled the Sykes' pattern of behavioral development. We suggest that this result reflects a sex-linked paternal effect.

Reciprocal painting between humans, De Brazza's and patas monkeys reveals a major bifurcation in the Cercopithecini phylogenetic tree.

We report on reciprocal painting between humans and two Cercopithecini species, Erythrocebus patas (patas monkey) and Cercopithecus neglectus (De Brazza's monkey). Both human and monkeys chromosome-specific probes were made by degenerate oligonucleotide primed PCR (DOP-PCR) from flow sorted chromosomes. Metaphases of both monkey species were first hybridized with human chromosome-specific probes and then human metaphases were hybridized with chromosome paints from each monkey species. The human paint probes detected 34 homologous segments on the C. neglectus karyotype, while the C. neglectus probes, including the Y, revealed 41 homologous segments on the human karyotype. The probes specific for human chromosomes detected 29 homologous segments in the E. patas karyotype, while the patas monkey probes painted 34 segments on the human karyotype. We tested various hypotheses of Cercopithecini phylogeny and taxonomy developed by morphologists, molecular biologists and cytogeneticists. Our hybridization data confirm that fissions (both Robertsonian and non-Robertsonian) are the main mechanism driving the evolutionary trend in Cercopithecini toward higher diploid numbers and strongly suggest an early phylogenetic bifurcation in Cercopithecini. One branch leads to Cercopithecus neglectus/Cercopithecus wolfi while the other line leads to Erythrocebus patas/Chlorocebus aethiops. Allenopithecus nigroviridis may have diverged prior to this major phylogenetic node.