Single‐Nucleotide Polymorphisms Reveal Patterns of Allele Sharing Across the Species Boundary Between Rhesus (Macaca mulatta) and Cynomolgus (M. fascicularis) Macaques

Both phenotypic and genetic evidence for asymmetric hybridization between rhesus (Macaca mulatta) and cynomolgus (Macaca fascicularis) macaques has been observed in the region of Indochina where both species are sympatric. The large‐scale sharing of major histocompatibility complex (MHC) class II alleles between the two species in this region supports the hypothesis that genes, and especially genes involved in immune response, are being transferred across the species boundary. This differential introgression has important implications for the incorporation of cynomolgus macaques of unknown geographic origin in biomedical research protocols. Our study found that for 2,808 single‐nucleotide polymorphism (SNP) markers, the minor allele frequencies (MAF) and observed heterozygosity calculated from a sample of Vietnamese cynomolgus macaques was significantly different from those calculated from samples of both Chinese rhesus and Indonesian cynomolgus macaques. SNP alleles from Chinese rhesus macaques were overrepresented in a sample of Vietnamese cynomolgus macaques relative to their Indonesian conspecifics and located in genes functionally related to the primary immune system. These results suggest that Indochinese cynomolgus macaques represent a genetically and immunologically distinct entity from Indonesian cynomolgus macaques. Am. J. Primatol. 75:135‐144, 2013. © 2012 Wiley Periodicals, Inc.     

Polyspecific groups of macaques on the kowloon peninsula,new territories,Hong Kong

Three polyspecific groups of free-ranging macaques were observed in July and August of 1980 and 1981 in the forests of the New Territories of mainland Hong Kong. Two groups were composed of rhesus monkeys (Macaca mulatta) and long-tailed or crab-eating monkeys (M. fascicularis), and one group was composed of both the former plus Japanese macaques (M. fuscata). All three groups contained hybrids between M. mulatta and M. fascicularis. This combination of species within the same social group is an unusual circumstance in natural habitats, and it offers a unique opportunity for field studies in primate ecology and behavior.     

Hemoglobin polymorphism in macaques with reference to the evolution ofMacaca fascicularis andMacaca mulatta

Blood samples were collected fromMacaca fascicularis andMacaca mulatta living in indoor breeding groups and investigated electrophoretically. Hemoglobin polymorphism was observed in both species. Isoelectric focusing was performed on urea denaturated samples to test the hypothesis of a site duplication at theα-chain locus inM. fascicularis (Barnicot et al., 1970). The results of our investigations do not support the above mentioned hypothesis. Only one locus coding theα-chain was detected, and this is under the control of two alleles. Evolutionary events at the molecular level are discussed, as well asWheatley's hypothesis (1980) that malaria was an important force behind divergence in both species. InM. fascicularis hemoglobin variants might be similarily connected with malaria resistance as in man. We suggest that this was not an important process behind speciation in macaques.     

Tail length variation inMacaca fascicularis andM. mulatta

Based on collectors' measurements of 1,040 specimens, variation of relative tail length [RTL = (tail length/head and body length) × 100] has been studied inMacaca fascicularis andM. mulatta, two closely related species that replace one another in tropical Asia and subtropical Asia, respectively. RTL usually is greater than 90 inM. fascicularis and usually is less than 60 inM. mulatta; intermediate values occur in only 3.5% of specimens studied. Within each species, RTL is approximately equal in females and males. From infancy to adulthood, RTL tends to decline in both species. InM. fascicularis, RTL generally decreases with increasing latitude; inM. mulatta, RTL is approximately constant latitudinally. Where the geographic ranges of these two species meet at ca. 15°N in the Indochinese Peninsula, a few specimens have been collected in which RTL and dorsal pelage color are intermediate between those inM. fascicularis andM. mulatta. The observed pattern of variation suggests that the ranges ofM. fascicularis andM. mulatta formerly were separated by a zoogeographic barrier — perhaps during a Pleistocene glacial interval. After disappearance of the postulated barrier, the ranges of these two species apparently became contiguous and limited hybridization has occurred.     

Y-Chromosome and Mitochondrial Markers in Macaca fascicularis Indicate Introgression with Indochinese M. mulatta and a Biogeographic Barrier in the Isthmus of Kra

This is the first report of Y-chromosome introgression between primate species. We sequenced 3.1 Kb of Y-chromosome DNA and 1.5 Kb of mtDNA for 27 macaques of Fooden's (Folia Primatol. [1976] 25: 225–236) fascicularis species group and 5 outgroup taxa (Macaca sylvanus, Papio hamadryas, Theropithecus gelada, Allenopithecus nigroviridis, and Cercopithecus mona). Phylogenies constructed separately for the paternal and maternal data sets show a Y-chromosome paraphyly among lineages of Macacafascicularis, but a mitochondrial monophyly for the same individuals. The Y-chromosome topology depicts Indochinese Macaca fascicularis haplotypes joining with those of M. mulatta, followed by M. cyclopis and M. fuscata, before clustering with a clade of lineages of M. fascicularis from peninsular Malaysia, Indonesia, and the Philippines. These contrasting patterns of mitochondrial and Y-chromosome DNA, evaluated in the context of the evolutionary consequences of macaque sex-biased dispersal, present strong evidence for contemporary hybridization between Macaca fascicularis and M. mulatta in Indochina and a biogeographic barrier in the Isthmus of Kra.     

Determining genetic background in captive stocks of cynomolgus macaques (Macaca fascicularis)

Background As in other model organisms, genetic background in the non‐human primates Macaca mulatta and Macaca fascicularis is an experimental variable that affects the response of other study variables. Genetic background in model organisms is manipulated by breeding schemes but is generally pre‐determined by the source population used to found captive stocks. In M. fascicularis three such sources have been distinguished, however, these are not routinely taken into consideration when designing research. Methods We exemplify a mitochondrial DNA (mtDNA)‐based strategy to trace the maternal geographic origins of M. fascicularis animals of unspecified origins. Results Macaca fascicularis of unspecified origins kept at primate research centers carry mtDNA haplotypes representing all three major genetic subdivisions. Conclusions We suggest that the genetic background of study animals could be better specified in the future using an mtDNA‐based approach, which would enable informed selection of study animals and help reduce variation within and among studies.     

Vocal communication of tonkean macaques in confined environments

Vocal recordings of one semi-free-ranging group and one captive group of Tonkean macaques (Macaca tonkeana) were used to establish the vocal repertoire of the species. Only the alpha male of the groups uttered a very distinctive loud call. Localization variants of coo calls were found. Alarm calls given by this species were acoustically similar to those by Japanese, rhesus, and long-tailed macaques (M. fuscata, M. mulatta, andM. fascicularis). Adult females uttered a specific variant of vocalizations during sexual morphological changes. The repertoire of agonistic vocalizations was more variable than that of any other macaque species investigated. These characteristics were discussed with reference to previous studies on vocalizations of macaque species.     

Phylogenetic Relationships of the Macaques (Cercopithecidae: Macaca), Inferred from Mitochondrial DNA Sequences

To study the phylogenetic relationships of the macaques, five gene fragments were sequenced from 40 individuals of eight species: Macaca mulatta, M. cyclopis, M. fascicularis, M. arctoides, M. assamensis, M. thibetana, M. silenus, and M. leonina. In addition, sequences of M. sylvanus were obtained from Genbank. A baboon was used as the outgroup. The phylogenetic trees were constructed using maximum-parsimony and Bayesian methods. Because five gene fragments were from the mitochondrial genome and were inherited as a single entity without recombination, we combined the five genes into a single analysis. The parsimony bootstrap proportions we obtained were higher than those from earlier studies based on the combined mtDNA dataset. Excluding M. arctoides, our results are generally consistent with the classification of Delson (1980). Our phylogenetic analyses agree with earlier studies suggesting that the mitochondrial lineages of M. arctoides share a close evolutionary relationship with the mitochondrial lineages of the fascicularis group of macaques (and M. fascicularis, specifically). M. mulatta (with respect to M. cyclopis), M. assamensis assamensis (with respect to M. thibetana), and M. leonina (with respect to M. silenus) are paraphyletic based on our analysis of mitochondrial genes.     

Preliminary report on yellow long-tailed macaques (Macaca fascicularis) at Kosumpee Forest Park, Thailand

We conducted a census on long-tailed macaques (Macaca fascicularis) at Kosumpee Forest Park, Thailand, and found 15 individuals of yellow pelage color out of a total of 287 individuals. There were three troops, designated A, B and C, but the yellow macaques were found only in B and C troops. The frequency of yellow macaques was 5.2% in the total population and 4.2 and 9.9% in B and C troops, respectively. These frequencies are much higher than those in rhesus macaques (M. mulatta) reared at Cayo Santiago (0.52%). They are, however, lower than those of 10 years ago.     

Quantitative analyses of cross-sectional shape of the distal radius in three species of macaques

I conducted quantitative analyses of the cross-sectional shape of the distal radial shaft in three species of macaques, which differ in locomotor behavior: semi-terrestrial Japanese macaques (Macaca fuscata), arboreal long tailed macaques (M. fascicularis), and relatively terrestrial rhesus macaques (M. mulatta). I took CT scans of the distal radial shafts of a total of 180 specimens at the level of the inferior radio-ulnar articulation. From each CT image, the periosteal outline of the radius was traced automatically by a digital imaging technique. I determined five points (landmarks) on the outline by developing a standardized morphometric technique. Bone surface lengths were measured by using these landmarks and their soft tissue correlates were investigated. The results of this study were as follows: (1) Semi-terrestrial M. fuscata has features that are approximately intermediate between those of the other two species. M. fuscata has a relatively small groove for M. abductor pollicis longus and a large groove for Mm. extensor carpi radialis longus et brevis. These characters resemble those of M. fascicularis. On the other hand, the ulnar notch of M. fuscata is relatively large, a character which is similar to that of M. mulatta. Moreover, compared to the other two macaques, the surface of the flexor muscles of M. fuscata is intermediate in size. (2) The more terrestrial M. mulatta has a relatively large groove for M. abductor pollicis longus and a small groove for Mm. extensor carpi radialis longus et brevis. Moreover, M. mulatta has a relatively large ulnar notch and a small surface for the flexor muscles. (3) The arboreal M. fascicularis has similar features to those of M. fuscata for the first and second relative size index. However, in the ulnar notch, M. fascicularis has a peculiar character and the surface for the flexor muscles is relatively large compared to those of the other two species. These results can be interpreted in terms of positional habits and presumed functional demands. A form-functional study by Lemelin and Schmitt also corroborates the interpretations of the present study. Thus, the distal region of the forearm strongly reflects muscular development and joint resultant force, and is an important region for investigating locomotor adaptations in primates. The present study reveals the possibility of using this type of morphometric analysis for reconstructing the positional behavior of fossil primates.     

Hybridization and Stratification of Nuclear Genetic Variation in Macaca mulatta and M. fascicularis

We used genotypes for 13 short tandem repeats (STRs) to assess the genetic diversity within and differentiation among populations of rhesus macaques (Macaca mulatta) from mainland Asia and long-tailed macaques (M. fascicularis) from mainland and insular Southeast Asia. The subjects were either recently captured in the wild or derived from wild-caught founders maintained in captivity for biomedical research. A large number of alleles are shared between the 2 macaque species but a significant genetic division between them persists. The distinction is more clear-cut among populations that are not, or are unlikely to have recently been, geographically contiguous. Our results suggest there has been significant interspecific nuclear gene flow between rhesus macaques and long-tailed macaques on the mainland. Comparisons of mainland and island populations of long-tailed macaques reflect marked genetic subdivisions due to barriers to migration. Geographic isolation has restricted gene flow, allowing island populations to become subdivided and genetically differentiated. Indonesian long-tailed macaques show evidence of long-term separation and genetic isolation from the mainland populations, whereas long-tailed macaques from the Philippines and Mauritius both display evidence of founder effects and subsequent isolation, with the impact from genetic drift being more profound in the latter.     

A genetic comparison of two alleged subspecies of Philippine cynomolgus macaques

Two subspecies of cynomolgus macaques (Macaca fascicularis) are alleged to co‐exist in the Philippines, M. f. philippensis in the north and M. f. fascicularis in the south. However, genetic differences between the cynomolgus macaques in the two regions have never been studied to document the propriety of their subspecies status. We genotyped samples of cynomolgus macaques from Batangas in southwestern Luzon and Zamboanga in southwestern Mindanao for 15 short tandem repeat (STR) loci and sequenced an 835 bp fragment of the mtDNA of these animals. The STR genotypes were compared with those of cynomolgus macaques from southern Sumatra, Singapore, Mauritius and Cambodia, and the mtDNA sequences of both Philippine populations were compared with those of cynomolgus macaques from southern Sumatra, Indonesia and Sarawak, Malaysia. We conducted STRUCTURE and PCA analyses based on the STRs and constructed a median joining network based on the mtDNA sequences. The Philippine population from Batangas exhibited much less genetic diversity and greater genetic divergence from all other populations, including the Philippine population from Zamboanga. Sequences from both Batangas and Zamboanga were most closely related to two different mtDNA haplotypes from Sarawak from which they are apparently derived. Those from Zamboanga were more recently derived than those from Batangas, consistent with their later arrival in the Philippines. However, clustering analyses do not support a sufficient genetic distinction of cynomolgus macaques from Batangas from other regional populations assigned to subspecies M. f. fascicularis to warrant the subspecies distinction M. f. philippensis. Am J Phys Anthropol 155:136–148, 2014. © 2014 Wiley Periodicals, Inc.     

Blood groups of bonnet macaques (Macaca radiata), with a brief introduction to seroprimatology

The human-type A-B-O blood groups of 52 bonnet macaques (Macaca radiata) were determined. Application of method of population genetics indicated the gene frequences to be O = 0.173, A = 0.480 and B = 0.347. Cross testing of sera and red cells of the bonnet macaques revealed two blood-type-specific isoagglutinins, one of them strong enough for use as a blood typing reagent. No blood group polymorphism was revealed by testing bonnet macaque red cells with isoantisera produced in rhesus monkeys (M. mulatta) and in crab-eating macaques (M. fascicularis). The rhesus and crab-eating macaque isoantisera reacted either with all or with none of the bonnet macaque red cells tested.     

Copulatory behavior in relation to anatomical characteristics of three macaques

Anatomy of copulatory organs and patterns of copulatory behavior were studied in three species of Macaca. The copulatory behavior of the rhesus monkey (M. mulatta) and crab-eating macaque (M. fascicularis) were similar. Mounting time was longer in stump-tailed macaque (M. arctoides) (48 seconds) than in the rhesus monkey or crab-eating macaque (8.5 seconds). Species differences were correlated with anatomical differences in the female and male reproductive organs. In the stump-tailed macaque the male has a relatively long penis, and the female has an elaborate vestibular colliculus in the vestibule. Both rhesus and crab-eating macaques have a short penis, and the female has no vestibular colliculus. Under scanning electron microscope, cone-like projections (3–4 mm) were observed on the surface of the glans and corpus penis of M. arctoides. In M. fascicularis shorter projections (0.05–0.1 mm) were observed on the glans penis but not the corpus penis.     

Geometric characters of the radius and tibia in <Emphasis Type="Italic">Macaca mulatta</Emphasis> and <Emphasis Type="Italic">Macaca fascicularis</Emphasis>

We performed comparative analyses of four cross-sections of the distal radius and tibia in two species of macaque to clarify the relationships between bone morphology and locomotor type. The lengths of bones and five bone geometric properties in each section were examined and compared separately in both female and male Macaca mulatta and Macaca fascicularis. In M. mulatta, there were no significant gender-specific differences in either the radius or the tibia. In contrast, the radius and tibia of male M. fascicularis had greater geometric parameters in the 20% and 40% positions relative to the 5% and 10% positions from the distal end than those of their female counterparts. The radius and tibia of M. mulatta were relatively longer than those of M. fascicularis, and the sectional parameters of the tibia of M. mulatta were relatively larger than those of M. fascicularis. Standardization of the log-transformed bone length between the species revealed larger radial cortical bone areas in M. fascicularis. In contrast, there were minimal differences in the tibial cortical bone areas between the two species. This study suggests that the observed distinctions in bone geometry in female and male M. fascicularis may be due to gender-specific differences in the muscle weights of the forearm and calf, which may underlie the divergence in the leaping abilities of females and males of this species. Taken together, these results of interspecies comparisons may be related to the fact that arboreal primates such as M. fascicularis undergo compressive mechanical stress due to the forelimb lead that occurs as the animal descends a sloping trunk or bridges a tree gap downward, while terrestrial primates such as M. mulatta move on nearly flat substrates. Differences in fore- and hind-limb bone properties between the two species are discussed with regard to functional morphology and locomotor type.     

Visual-optical characteristics of caged and semifree-ranging monkeys

Five species of macaques and one species of mangabey comprising a total of 324 monkeys (132 males and 192 females) were given visual examinations which included measures of corneal curvature, depth of the anterior chamber, thickness of the lens, depth of the vitreous chamber, total axial length, total power of the eye and intraocular pressure as well as the refractive error of eye under cycloplegia in the anesthetized monkey. Cercocebus and Macaca mulatta demonstrated the greatest amount of myopia and Macaca fascicularis the least, with M. speciosa, M. fuscata, and M. nemestrina in order between these extremes. The M. nemestrina eye approximates that of the chimpanzee in size and relationship of the components. The findings indicate that males have larger eyes than females, the curvature of the cornea decreases as the axial length increases, and there is a close relationship between the length of the eye and the amount of myopic refractive error. There is some evidence that amount of myopia and the percentage of animals showing a myopic refractive error are related to the visual conditions and the behavior patterns of the different species.     

Analysis of the expressed heavy chain variable-region genes of Macaca fascicularis and isolation of monoclonal antibodies specific for the Ebola virus' soluble glycoprotein

The cynomolgus macaque, Macaca fascicularis, is frequently used in immunological and other biomedical research as a model for man; understanding it's antibody repertoire is, therefore, of fundamental interest. The expressed variable-region gene repertoire of a single M. fascicularis, which was immune to the Ebola virus, was studied. Using 5′ rapid amplification of cDNA ends with immunoglobulin (Ig)G-specific primers, we obtained 30 clones encoding full-length variable, diversity, and joining domains. Similar to the human V_H repertoire, the M. fascicularis repertoire utilized numerous immunoglobulin heavy variable (IGHV) gene fragments, with the V_H3 (41%), V_H4 (39%), and V_H1 (14%) subgroups used more frequently than the V_H5 (3.9%) or V_H7 (1.7%) subgroups. Diverse immunoglobulin heavy joining (IGHJ) fragments also appeared to be utilized, including a putative homolog of JH5β gene segment identified in the related species Macaca mulatta, Rhesus macaque, but not in humans. Although the diverse V region genes in the IgG antibody repertoire of M. fascicularis had likely undergone somatic hypermutations (SHMs), they nevertheless showed high nucleotide identity with the corresponding human germline genes, 80–89% for IGHV and 72–92% for IGHJ. M. fascicularis and human V_H genes were also similar in other aspects: length of complementarity-determining regions and framework regions, and distribution of consensus sites for SHMs. Finally, we demonstrated that monoclonal antibodies (mAbs) specific for an Ebola protein could be obtained from M. fascicularis tissue samples by phage display technology. In summary, the study provides new insight into the M. fascicularis V region gene repertoire and further supports the idea that macaque-derived mAbs may be of therapeutic value to humans.     

Serum albumin and erythrocyte adenosine deaminase polymorphisms in Asian macaques with special reference to taxonomic relationships amongMacaca assamensis,M. radiata,andM. mulatta

Serum albumin (Alb) and erythrocyte adenosine deaminase (ADA) polymorphisms in Asian macaques were investigated by means of starch gel electrophoresis. The materials comprise a total of 2,323 blood samples from eight species, namely,Macaca fuscata,M. mulatta,M. cyclopis,M. fascicularis,M. nemestrina,M. speciosa,M. radiata, andM. assamensis. It was observed that three Alb phenotypes were controlled by two codominant alleles, Alb _mac ^A and Alb _mac ^B and six ADA phenotypes by four codominant alleles, ADA _mac ¹ , ADA _mac ² , ADA _mac ³ , and ADA _mac ⁴ . The taxonomic relationships amongM. assamensis,M. radiata, andM. mulatta were analyzed by measuring theNei's (1975) genetic distance. The result supportedHill andBernstein's (1969) postulation thatM. assamensis was more closely related phylogenetically toM. radiata than toM. mulatta.     

G-banding in the barbary macaque (Macaca sylvanus, Linnaeus, 1758) of Morocco

G-banding was performed on the lymphocytes of six barbary macaques (Macaca sylvanus). Four chromosomes appear to have polymorphic variants: number 1, number 4, number 16, and the “marker” chromosome, number 9. These polymorphic forms differe from the G-banding reported for Macaca mulatta, Macaca fascicularis, and Macaca arctoides. It may be that evolutionary relationships among various macaque species can be ascertained by using such chromosomal polymorphisms.