Distribution of U5 antigen on lymphocyte subsets in human and nonhuman primates

The U5 monoclonal antibody developed by immunizing mice with Japanese monkey lymphocytes could react with lymphocytes of primate species including Old World monkeys, apes, and human. However, the distributions of U5 antigen on major functional subsets of lymphocytes were different in primate species. The U5 antigen was mainly distributed on natural killer (NK) cells in human, but on B cells in Old World monkeys. On the other hand, U5 antigen was detected on both B and NK cells in chimpanzees and gibbons, indicating that the distribution of U5 antigen on lymphocyte might change from B cells to NK cells during primate evolution.     

Evolution of exon 1 of the dopamine D4 receptor (DRD4) gene in primates

The dopamine D4 receptor (DRD4) gene exhibits a large amount of expressed polymorphism in humans. To understand the evolutionary history of the first exon of DRD4-which in humans contains a polymorphic 12bp tandem duplication, a polymorphic 13bp deletion, and other rare variants-we examined the homologous exon in thirteen other primate species. The great apes possess a variable number of tandem repeats in the same region as humans, both within and among species. In this sense, the 12bp tandem repeat of exon 1 is similar to the 48bp VNTR of exon 3 of DRD4, previously shown to be polymorphic in all primate species examined. The Old World monkeys show no variation in length, and a much higher conservation of amino acid sequence than great apes and humans. The New World monkeys show interspecific differences in length in the region of the 12bp polymorphism, but otherwise show the higher conservation seen in Old World monkeys. The different patterns of variation in monkeys compared to apes suggest strong purifying selective pressure on the exon in these monkeys, and somewhat different selection, possibly relaxed selection, in the apes.     

Investigation of the human Rh blood group system in nonhuman primates and other species with serologic and Southern blot analysis

To investigate the evolution of the Rh blood-group system in anthropoid apes, New and Old World monkeys, and nonprimate animals, serologic typing of erythrocytes from these species with antibodies specific for the human Rh blood-group antigens was performed. In addition, genomic DNA from these animals was analyzed on Southern blots with a human Rh-specific cDNA.Consistent with earlier reports, serologic results showed that gorilla and chimpanzee erythrocytes had epitopes recognized by human Rh D and c antisera, and gibbon erythrocytes were recognized by the c antisera. Surprisingly, some Old and New World monkeys also expressed a Rh c epitope on their erythrocytes. No erythrocytes from the nonprimate animals reacted specifically with any of the human Rh antisera.Southern blot analysis with a human Rh-specific cDNA probe detected Rh-related sequences in anthropoid apes, all New and Old World monkeys, and in most nonprimate animals tested. Although some Rh-related restriction fragments were conserved across species lines in primates, the Rh locus was more polymorphic in chimpanzees and gorillas than in humans. In addition, restriction fragments segregating with the presence of the D antigen in humans were present in the primate species that expressed the D antigen.     

Color discrimination by the cotton-top tamarin (Saguinus oedipus oedipus) and its relation to fruit coloration

Old World monkeys and apes have been reported to differ from New World monkeys in their abilities to discriminate colors across the visible spectrum. Old World monkeys and apes (Macaca, Pan, Pongo) discriminate colors quite accurately, while some New World monkeys studied (Saimiri, Cebus) have shown lower sensitivity to and poorer discrimination of long wavelength light. This study examined the color discrimination ability of another New World primate, the cotton-top tamarin, Saguinus oedipus oedipus (family Callitrichidae). The tamarins were trained to discriminate a set of Munsell color chips, both within the same hue category and from the 2 hue categories on either side of the training hue. Results indicated that the cotton-top tamarin can make accurate discriminations across the visible spectrum. Human subjects were tested under similar conditions in order to compare their color discrimination abilities to those of the tamarins. The tamarins and human subjects had the most difficulty discriminating the same hues. The discrimination abilities of the monkeys were assessed in relation to the coloration of fruits eaten in a natural environment. A list of the species of fruits commonly eaten by various species of New World monkeys was compiled and the coloration of fruits at maturity was noted. It was found that most New World primate species eat fruits whose mature coloration ranges across most of the spectrum.     

Is the Clavicle of Apes Long? An Investigation of Clavicular Length in Relation to Body Mass and Upper Thoracic Width

An elongated clavicle is one of the distinct features of apes and humans. It plays an important role in providing mobility as well as stability for the shoulder joints. The relative length of the clavicle is an especially important factor in limiting the range of shoulder joint excursion. It is said that among primates, Asian apes, i.e., gibbons and orang-utans, have very long clavicles. At the same time, they also have a wide upper thoracic cage, which may diminish the effective length of the clavicle. To clarify the length of the clavicle in apes, from the standpoint of the functional anatomy of the shoulder girdle, we examined clavicular length in 15 anthropoid species exhibiting various positional behaviors. The results confirm that clavicle length in Asian apes is long, and chimpanzees have a short clavicle like that of Old and New World monkeys, when scaled to body mass. The clavicular length of chimpanzees, however, is intermediate between Old World monkeys and Asian apes when scaled against thoracic width. Therefore, living apes can be grouped together, albeit just barely, by possession of a relatively long clavicle for their thoracic cage size. Interestingly, New World monkeys tend to exhibit a longer clavicle than Old World monkeys of equivalent body mass or thoracic cage width. Although it is unclear whether the ancestral condition of clavicular length in anthropoids was similar to that of living Old or New World monkeys, an elongation of clavicle was an important step toward evolution of the modern body plan of hominoids.     

Distribution of dorsal carriage among simians

We surveyed the literature and obtained information from primate researchers and zookeepers to study the distribution of dorsal carriage among 77 simian species including New and Old World monkeys and apes in relation to arboreality and terrestriality, birth (litter) weight relative to maternal weight, and presence or absence of distinct natal coat colors. All New World monkeys are arboreal and commonly carry their infants dorsally. Conversely, arboreal Old World monkeys do not use dorsal carriage, and only some predominantly terrestrial Old World monkeys do so. Whereas lesser apes (which are highly arboreal) do not use dorsal carriage, arboreal as well as more terrestrial great apes commonly carry their infants dorsally. These findings indicate that simple arboreality or terrestriality is inadequate to explain dorsal carriage by monkeys. Infants of small- to medium-sized New World monkeys have relatively high birth weight compared with maternal weight, and are most likely to be carried dorsally than ventrally even on the first postnatal day. In contrast, infants of large-bodied New World monkeys are carried ventrally first and then dorsally up to the end of their second year, albeit increasingly infrequently. Among Old World monkeys, no association was found between mode of infant transport and birth weight relative to maternal weight, but some terrestrial Old World monkeys displaying dorsal carriage tend to do so with older infants, indicating that such behavior enables the mother to transport the infant with lower energy expenditure. Among terrestrial Old World monkeys, infants with distinctive natal coat colors are rarely carried dorsally until the natal coat color changes to adult coloration: infants with distinctive coat colors clinging to the backs of carriers could be highly visible and thus vulnerable to predation. Dorsal carriage by mothers may prolong the affiliative mother–infant relationship.     

Loss of olfactory receptor genes coincides with the acquisition of full trichromatic vision in primates

Olfactory receptor (OR) genes constitute the molecular basis for the sense of smell and are encoded by the largest gene family in mammalian genomes. Previous studies suggested that the proportion of pseudogenes in the OR gene family is significantly larger in humans than in other apes and significantly larger in apes than in the mouse. To investigate the process of degeneration of the olfactory repertoire in primates, we estimated the proportion of OR pseudogenes in 19 primate species by surveying randomly chosen subsets of 100 OR genes from each species. We find that apes, Old World monkeys and one New World monkey, the howler monkey, have a significantly higher proportion of OR pseudogenes than do other New World monkeys or the lemur (a prosimian). Strikingly, the howler monkey is also the only New World monkey to possess full trichromatic vision, along with Old World monkeys and apes. Our findings suggest that the deterioration of the olfactory repertoire occurred concomitant with the acquisition of full trichromatic color vision in primates.     

Anti-human red cell monoclonal antibodies produced by macaque-mouse heterohybridomas.

Eight monoclonal antibodies (Mabs) against human red cells were produced by macaque-mouse heterohybridomas. All Mabs uniformly reacted with all human red blood cells tested, but only some agglutinated the red cells of anthropoid apes occasionally detecting intraspecies polymorphisms. None was reactive with blood of Old and New World monkeys. One of the Mabs recognized the Vc antigen of the chimpanzee V-A-B-D system, the homologue of the human M-N blood group system.     

A test of the karyotypic fissioning theory of primate evolution

Karyotypic fissioning theory has been put forward by a number of researchers as a possible driving force of mammalian evolution. Most recently, Giusto and Margulis (BioSystems, 13 (1981) 267–302) hypothesized that karyotypic fissioning best explains the evolution of Old World monkeys, apes, and humans. According to their hypothesis, hominoid karyotypes were derived from the monkey chromosome complement by just such such a fissioning event. That hypothesis is tested here by comparing the G-banded chromosomes of humans and great apes with eight species of Old World monkeys. Five submetacentric chromosomes between apes and monkeys have identical banding patterns and nine chromosomes share the same pericentric inversion. Such extensive karyological similarities are not in accodance with, or predicted by karyotypic fissioning. Apparently, karyotypic fissioning is an extremely uneconomical model of chromosomal evolution. The strong conservation of banding patterns sometimes involving the retention of identical chromosomes indicates that ancient linkages of genes have probably been maintained through many speciation events.     

Distribution of human endogenous retrovirus HERV-K genomes in humans and different primates

The distribution of the human endogenous retrovirus (HERV)-K genome was investigated by Southern-blot analyses using a HERV-K-env DNA probe. With the exception of one DNA-sample, obtained from a Chinese individual in whom an amplification of HERV-K was detected, Southern-blot analyses yielded identical hybridization patterns with DNA from peripheral blood lymphocytes of 37 normal healthy blood donors, with DNA from six tumor cell lines, or with 23 DNA samples prepared from various carcinoma tissues. To elucidate whether the integration of HERV-K genomes into the primate lineage occurred as a single event or as an integration with later expansion, we further examined the evolutionary history of HERV-K by Southern blot analyses with DNA samples from different primate species. We detected HERV-K genomes in Macaca mulatta and Macaca silenus, which represent Old World monkeys, but not in prosimians (Galago demidovii) and New World monkeys, represented by Saguinus fuscicollis, Saguinus oedipus, and Calliihrix iacchus. Thus, we assume that the infection of the primate lineage with HERV-K had occurred after the divergence of New World and Old World monkeys, but before the evolutionary expansion of large hominoids. In contrast to the apparent lack of HERV-Kenv sequences in DNA from tissue of the New World monkey Saguinus oedipus (cotton-top marmoset), we found HERV-K-DNA in the B95-8 cell-line, which is a Saguinus oedipus leukocyte cell-line, immortalized in vitro by Epstein-Barr virus (EBV) and cultivated in human cells. It may be speculated that HERV-K-DNA or HERV-K-particles were introduced into these cells during in vitro transformation with EBV.     

Prevalence of rotavirus and norovirus antibodies in non-human primates

Rotavirus and norovirus are associated with a substantial burden of diarrheal disease in humans and some animals, but their role in acute viral gastroenteritis in non-human primates has not been established. We examined sera from five species of Old and New World monkeys and chimpanzees for antibodies to rotavirus and norovirus by enzyme immunoassays using RRV and three recombinant human norovirus capsid proteins, respectively. Most (88%) of the 3 Old World monkey species (mangabey, pigtail, and rhesus) and apes were seropositive for rotavirus. Norovirus antibody was prevalent in the three monkey species, with 53% (44/83) and 58% (48/83) seropositive for GI and GII strains, respectively. Eleven (92%) of the 12 chimpanzees tested were seropositive for GI norovirus. Given the high rate of infection with both viruses, the role of these agents in causing acute gastroenteritis in non-human primates and the value of these animals as models of infection and disease need to be assessed.     

Infection of Human B Lymphocytes with Lymphocryptoviruses Related to Epstein-Barr Virus

Lymphocryptoviruses (LCVs) naturally infecting Old World nonhuman primates are closely related to the human LCV, Epstein-Barr virus (EBV), and share similar genome organization and sequences, biologic properties, epidemiology, and pathogenesis. LCVs can efficiently immortalize B lymphocytes from the autologous species, but the ability of a given LCV to immortalize B cells from other Old World primate species is variable. We found that LCV from rhesus monkeys did not immortalize human B cells, and EBV did not immortalize rhesus monkey B cells. In this study, baboon LCV could not immortalize human peripheral blood B cells but could readily immortalize rhesus monkey B cells. Thus, efficient LCV-induced B-cell immortalization across distant Old World primate species appears to be restricted by a species-specific block. To further characterize this species restriction, we first cloned the rhesus monkey LCV major membrane glycoprotein and discovered that the binding epitope for the EBV receptor, CD21, was highly conserved. Stable infections of human B cells with recombinant amplicons packaged in rhesus monkey or baboon LCV envelopes were also consistent with a species-restricted block occurring after virus binding and penetration. Transient infections of human B cells with simian LCV resulted in latent LCV EBNA-2 gene expression and activation of cell CD23 gene expression. EBV-immortalized human B cells could be coinfected with baboon LCV, and the simian virus persisted and replicated in human B cells. Thus, several lines of evidence indicate that the species restriction for efficient LCV-induced B-cell immortalization occurs beyond virus binding and penetration. This has important implications for the study of LCV infection in Old World primate models and for human xenotransplantation where simian LCVs may be inadvertently introduced into humans.     

Distribution of Mason-Pfizer Virus-Specific Sequences in the DNA of Primates

Iodinated Mason-Pfizer virus (MPV) 60-70S RNA has been used in molecular hybridization experiments to determine the distribution of MPV-specific proviral sequences in the DNAs of primates. Approximately 20% of the MPV genome is present as endogenous provirus in rhesus monkeys. Competitive hybridization experiments showed no homology between MPV 60-70S RNA and the 60-70S RNAs of M7, RD-114, and the simian sarcoma virus. No MPV-specific proviral sequences were detected in the DNAs of apparently normal tissues of various species of New World monkeys, apes, and humans. The part of the MPV genome that is endogenous to rhesus is also endogenous to the other species of Old World monkeys examined: baboon, African green, and patas. This was determined as a result of the following observations: (i) C(0)t(1/2) values and final extent of hybridization were the same for all four species. (ii) T(m) values of MPV 60-70S RNA and DNA of all four species were identical. (iii) The removal of MPV sequences endogenous to rhesus tissues by recycling against rhesus DNA resulted in the loss of any hybridizable MPV RNA to the DNAs of baboon, African green, and patas tissues. (iv) Mixing experiments of rhesus, African green, and baboon DNAs resulted in the same kinetics of hybridization as did rhesus DNA alone, when hybridized with MPV 60-70S RNA. These findings demonstrate that sequences that constitute an integral part of the MPV genome are conserved in the DNAs of several different species of Old World monkeys.     

Uniformity of colour vision in Old World monkeys

It is often assumed that all Old World monkeys share the same trichromatic colour vision, but the evidence in support of this conclusion is sparse as only a small fraction of all Old World monkey species have been tested. To address this issue, spectral sensitivity functions were measured in animals from eight species of Old World monkey (five cercopithecine species and three colobine species) using a non-invasive electrophysiological technique. Each of the 25 animals examined had spectrally well-separated middle- and long-wavelength cone pigments. Cone pigments maximally sensitive to short wavelengths were also detected, implying the presence of trichromatic colour vision. Direct comparisons of the spectral sensitivity functions of Old World monkeys suggest there are no significant variations in the spectral positions of the cone pigments underlying the trichromatic colour vision of Old World monkeys.     

Structure and evolution of the U2 small nuclear RNA multigene family in primates: gene amplification under natural selection?

The organization of U2 genes was compared in apes, Old World monkeys, and the prosimian galago. In humans and all apes (gibbon, orangutan, gorilla, and chimpanzee), the U2 genes were organized as a tandem repeat of a 6-kb element; however, the restriction maps of the 6-kb elements in these divergent species differed slightly, demonstrating that mechanisms must exist for maintaining sequence homogeneity within this tandem array. In Old World monkeys, the U2 genes were organized as a tandem repeat of an 11-kb element; the restriction maps of the 11-kb elements in baboon and two closely related macaques, bonnet and rhesus monkeys, also differed slightly, confirming that efficient sequence homogenization is an intrinsic property of the U2 tandem array. Interestingly, the 11-kb monkey repeat unit differed from the 6-kb hominid repeat unit by a 5-kb block of monkey-specific sequence. Finally, we found that the U2 genes of the prosimian galago were dispersed rather than tandemly repeated, suggesting that the hominid and Old World monkey U2 tandem arrays resulted from independent amplifications of a common ancestral U2 gene. Alternatively, the 5-kb monkey-specific sequence could have been inserted into the 6-kb array or deleted from the 11-kb array soon after divergence of the hominid and Old World monkey lineages.     

Fatty acid composition of wild anthropoid primate milks

Fatty acids in milk reflect the interplay between species-specific physiological mechanisms and maternal diet. Anthropoid primates (apes, Old and New World monkeys) vary in patterns of growth and development and dietary strategies. Milk fatty acid profiles also are predicted to vary widely. This study investigates milk fatty acid composition of five wild anthropoids (Alouatta palliata, Callithrix jacchus, Gorilla beringei beringei, Leontopithecus rosalia, Macaca sinica) to test the null hypothesis of a generalized anthropoid milk fatty acid composition. Milk from New and Old World monkeys had significantly more 8:0 and 10:0 than milk from apes. The leaf eating species G. b. beringei and A. paliatta had a significantly higher proportion of milk 18:3n-3, a fatty acid found primarily in plant lipids. Mean percent composition of 22:6n-3 was significantly different among monkeys and apes, but was similar to the lowest reported values for human milk. Mountain gorillas were unique among anthropoids in the high proportion of milk 20:4n-6. This seems to be unrelated to requirements of a larger brain and may instead reflect species-specific metabolic processes or an unknown source of this fatty acid in the mountain gorilla diet.     

Molecular evolution of IgG subclass among nonhuman primates: implication of differences in antigenic determinants among Apes

The cross-reactivity of five different rabbit polyclonal antibodies to human IgG and IgG subclass (IgG1, IgG2, IgG3, and IgG4) was determined by competitive ELISA with nine nonhuman primate species including five apes, three Old World monkeys, and one New World monkey. As similar to those previously reported, the reactivity of anti-human IgG antibody with plasma from different primate species was closely related with phylogenic distance from human. Every anti-human IgG subclass antibody showed low cross-reactivity with plasma from Old World and New World monkeys. The plasma from all apes except for gibbons (Hylobates spp.) showed 60 to 100% of cross-reactivity with anti-human IgG2 and IgG3 antibodies. On the other hand, chimpanzee (Pan troglodytes andPan paniscus) and orangutan (Pongo pygmaeus) plasma showed 100% cross-reactivity with anti-human IgG1 antibody, but gorilla (Gorilla gorilla) and gibbon plasma showed no cross-reactivity. The chimpanzee and gorilla plasma cross-reacted with anti-human IgG4 antibody at different reactivity, 100% in chimpanzee and 50% in gorilla, but no cross-reactivity was observed in orangutan and gibbon plasma. These results suggest the possibilities that the divergence of “human-type” IgG subclasses might occur at the time of divergence ofHomo sapience fromHylobatidae, and that the molecular evolution of IgG1 as well as IgG4 is different from that of IgG2 and IgG3 in great apes, this is probably caused by different in development of immune function in apes during the course of evolution.