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PubMed2005

Primate spermatogenesis: new insights into comparative testicular organisation, spermatogenic efficiency and endocrine control.

Owing to the close phylogenetic relationship of Platyrrhini (New World monkeys) and Catarrhini (Old World monkeys) to man, nonhuman primates are often used as models for the study of male reproductive physiology and endocrinology. This review aims at providing new data and insights into comparative primate spermatogenesis, dealing specifically with quantitative aspects of germinal epithelial organisation and germ cell production, and with the roles of gonadotrophic hormones in this process. Typically, the seminiferous epithelium is composed of specific germ cell associations (spermatogenic stages). In rodents, prosimians and most Catarrhini, tubular cross sections contain a single spermatogenic stage whereas in Platyrrhini, great apes and man multi-stage tubules are present. Since Platyrrhini represent a more basal type of primate, this spermatogenic feature must have developed convergently. The primate multi-stage tubular arrangement was previously believed to be associated with low spermatogenic efficiency. However, recent studies using new methodological approaches and comparing primate species from all taxa have revealed that multistage organisation is compatible with highly efficient spermatogenesis. In fact, meta-analysis demonstrated that the efficiency of spermatogenesis in several nonhuman primate species is comparable to that of rodents which are considered as species with highly efficient germ cell production. The duration of the spermatogenic process was not related to organisation or efficiency of spermatogenesis. Sertoli cell work load was species-specific but had no impact on germ cell numbers and on the efficiency of spermatogenesis. The gonadotrophic hormones, luteinizing hormone (LH) and follicle stimulating hormone (FSH) are the primary regulators of primate testicular function. Recent studies revealed that in New World monkeys chorionic gonadotrophin (CG)--the primate pregnancy hormone--regulates testosterone production instead of LH. Receptor studies demonstrated a dual action of the closely related hormones LH and CG in primates. It is hypothesised that following the divergence of the Platyrrhini lineage from Catarrhini, the LH/CG system evolved independently with ancestral functions of the LH/CG system retained in the neotropical taxa. In summary, key spermatogenic features are preserved across all primate taxa whereas male reproductive endocrinology features appear substantially different in the neotropical primates compared to other primate lineages.

Animals↗
PubMed2004

Primate communities: past, present, and possible future.

An understanding of the fundamental causes of the structure of primate communities is important for studies of primate evolutionary history, primate behavioral ecology, and development of conservation strategies. Research into these structuring factors has benefited from new perspectives such as consideration of primate phylogenetic history, metacommunities, and interactions with predators and nonprimate competitors. This review presents the underlying factors of primate community structure within the biogeographic regions of Madagascar, the Neotropics, Africa, and Asia. One of the major differences among these locations likely resulted from the initial primate taxa that colonized each region (a single colonization event in the case of Madagascar and South America, and multiple radiations of higher-level taxa in Africa and Asia). As most primates live in forests, the differences among the forests in these locations, caused by various climatic influences, further influenced speciation and the development of primate communities. Within these habitats, species interactions with different groups of organisms were also instrumental in developing community dynamics. Through an investigation of these fundamental factors, we identify some of the most important effects on primate communities in each region. These findings suggest that low primate richness in Asia may be caused by either the abundance of dipterocarp trees or high levels of monsoon rains. High numbers of frugivores and a lack of folivores in neotropical communities may be associated with competition with sloths that were already present at the time of initial radiation. Climatic patterns which affect forest structure and productivity in Madagascar may be responsible for high numbers of folivorous lemurs. The identification of these factors are important for the conservation of existing primate communities, and indicate directions for future studies.

Africa↗
PubMed2004

A shrew-sized origin for primates.

The origin of primates has had a long history of discussion and debate, with few ever considering the impact of the original body weight on subsequent primate adaptive radiations. Here, I attempt to reconstruct early primate evolution by considering the initial size of primates as well as the critical functional-adaptive events that had to occur prior to the early Eocene. Microcebus is often viewed as a living model, and thus 40-65 g might represent a practical ancestral weight for the origin of primates. I consider a smaller original body weight, likely 10-15 g in actual size, and I address the biological implications for shrew-sized primates by comparing the behavioral ecology of mouse lemurs, our smallest living primates, to another tiny-sized mammalian group, the shrews (Family Soricidae). Several behavioral and ecological characteristics are shared by shrews and mouse lemurs, and several mammalian trends are evident with decreased size. I suggest that a shrew-sized ancestral primate would have had high metabolic, reproductive, and predation rates, relatively low population densities, and a dispersed and solitary existence with a promiscuous mating system. Although small mammals like shrews provide insights concerning the ancestral size of primates, primate origins have always been tied to arboreality. I assess other potential arboreal models such as Ptilocercus and Caluromys. By combining all of this information, I try to sequence the events in a functional-adaptive series that had to occur before the early Eocene primate radiations. I suggest that all of these important adaptive events had to occur at a small body size below 50 g.

Adaptation, Physiological↗
PubMed1985

[The social structure of primates].

A comprehensive comparative study of the social structure of primates revealed: There is no social structure which can be considered typical and discriminative for primates. The varying social structures of the extant primate genera cannot be derived from each other: In contrast it seems that the basic, ancestral condition was that of solitary living animals, loosely aggregated. It can be assumed that the development to a gregarious society took place in two entirely different ways. In terms of primate phylogeny this different development can be shown for the prosimians as well as for the old world and new world monkeys as independently occurring processes. One way of behavioral specialization resulted in close pair bonds or in small family groups, whereas the other led to female groups. The presupposition for the forming of a society based on female groups is the close contact between the individuals and in addition to this, a remarkable social tolerance of females to each other. Social specializations which can be considered transitional from the basic condition are frequently found in prosimians. The kinds of social structures of the particular genera are in close relation to their taxonomic positions in the phylogenetic scala. The number of males in larger social groups of primates is substantially irrelevant as the groups are socially most dependent on the females. The protecting males are socially peripheral. The social units of most of the primate species are matrilocal and endure for several generations. In contrast, the social units of the gibbons and of the pongids are patrilocal and are established anew by the females in each generation. Consequently the social unit disintegrates on the death of the male. In all genera studied, male and female individuals present considerable behavioral differences which can be found even in juveniles. Primates are able to discriminate well known and confident individuals from other less confident; they prefer more confident individuals to less confident ones, and less confident to non-confident. As a consequence of this discriminative ability there is a clear preference for near when compared to distant relatives. The complexity of the social relations is brought about by this ability to discriminate combined with the longevity of primates. This is a characteristic and discriminative feature of the primate order. Dominance relations occur in every social group of primates. Linear hierarchies of dominance have been developed only once in prosimians (Lemur) and also once in simians (Cercopithecinae). Therefore, liner hierarchies are not typical for primates.

Age Factors↗
PubMed2002

Chronology of primate discoveries in Myanmar: influences on the anthropoid origins debate.

The history of primate paleontology in Asia is long and complex, beginning with the first discoveries of fossil primates on the Indian subcontinent in the early 1830's. The first Eocene mammals from Asia were collected in Myanmar and described in 1916, while the first primates, Pondaungia and Amphipithecus, were described in 1927 and 1937, respectively, both from the Pondaung Formation in Myanmar. For the next 60 years, these two Pondaung taxa remained as the only known Eocene primates from Myanmar and one of the few records of Eocene primates from all of Asia. Taxonomically, Pondaungia and Amphipithecus were linked with a number of different groups, including archaic, hoofed ungulates (condylarths), adapiform primates, omomyid primates, and anthropoids. While no consensus existed, Pondaungia and Amphipithecus were most commonly compared with anthropoids. Beginning in the late 1990s, new primates were discovered in Myanmar, including smaller-bodied forms such as Bahinia and Myanmarpithecus. Also, new and better specimens of the larger-bodied Pondaungia and Amphipithecus began to appear, including the first cranial and postcranial fragments. Evaluations based on these new specimens, especially the postcrania, indicate that the two larger-bodied Myanmar taxa are adapiform primates that show their closest affinities to North American notharctines. The smaller-bodied taxa remain enigmatic, but may share their closest affinities with North American and Asian omomyid primates and Asian Tarsius. None of the known Asian primate taxa appear closely related to African anthropoids, which suggests that true anthropoids did not reach Asia until the latest Oligocene or earliest Miocene. These facts make an Asian origin for Anthropoidea unlikely. Additional and earlier evidence from both Asia and Africa is required before the ultimate origin of anthropoids can be determined. It appears possible that true anthropoids were an ancient radiation that may have been part of a Gondwanan (southern hemisphere) community that is, at present, poorly sampled and little understood.

Animals↗
PubMed1987

Structure and evolution of primate cytochrome c oxidase subunit II gene.

The sequence of cytochrome oxidase subunit II (COII) mRNA from the cynomolgus macaque has been determined. Availability of the sequence from a non-human primate has allowed examination of the evolution of the COII gene and protein along the primate lineage. Comparison with existing protein and DNA sequences, combined with estimates of divergence derived from calculations designed to compensate for multiple mutation and reversion events, indicates that although the rate of fixation of nucleotide substitutions at silent sites is somewhat lower in primates than non-primates, the rate of fixation at replacement sites is 4-5-fold higher. The data also suggest that the rate of divergence at replacement sites along the primate lineage has not been uniform, but has decreased 2-2.5-fold since the higher primate branch point, in the absence of a comparable change in the rate substitution at silent sites. Both primate mRNAs differ from their non-primate homologues in having 3'-untranslated regions of 20-25 nucleotides. Examination of the monkey and human untranslated sequences suggests that these regions have evolved by duplication events occurring in both cases within 2-3 nucleotides following the translational stop codon. The primate mRNAs are also exceptional in that both can form stable stem and loop structures immediately preceding the postulated duplication site that may have played a role in facilitating the mutational events involved. Comparison of the human and monkey protein sequences has revealed regions conserved in primates that are significantly more hydrophobic than their non-primate counterparts. The possible effects of these alterations on the interaction between COII and cytochrome c are discussed.

Amino Acid Sequence↗
PubMed1998

Forests without primates: primate/plant codependency.

Detailed studies of primates and fruiting trees have illustrated that these groups of organisms are involved in a very complex set of interactions, with primates relying on fruiting trees as important food resources and fruiting trees relying on frugivores for seed dispersal. Human activities that influence either primate seed dispersal or fruit production have the potential of having unanticipated effects on the other interactants. Here we evaluate what is known and what we still need to learn to evaluate the long-term consequences of disrupting the interactions between primates and tropical forest trees. We do this by first assessing the potential importance of primates at dispersing the seeds of tropical forest trees. Second, we consider possible consequences of hunting primates on recruitment in tropical tree communities. Third, we address the converse by considering the impacts of decreasing resource availability for primates through either logging or through the extraction of nontimber forest products. Finally, we provide a case study from Kibale National Park, Uganda, that contrasts seedling recruitment in 20 forest fragments in which primate seed dispersers have been dramatically reduced with seedling recruitment in areas that have an intact frugivore community. In comparison to the intact forest, the fragments had lower seedling density and fewer species of seedlings. Furthermore, a greater proportion of the seedlings were from small-seeded species that might not require primates for their dispersal, since they probably can be dispersed by small birds. All of these considerations suggest that disrupting the complex interactions between primates and fruiting trees can potentially have negative and possibly cascading effects on ecosystem processes.

Animals↗
PubMed2004

Substrate alters forelimb to hindlimb peak force ratios in primates.

It is often claimed that the walking gaits of primates are unusual because, unlike most other mammals, primates appear to have higher vertical peak ground reaction forces on their hindlimbs than on their forelimbs. Many researchers have argued that this pattern of ground reaction force distribution is part of a general adaptation to arboreal locomotion. This argument is frequently used to support models of primate locomotor evolution. Unfortunately, little is known about the force distribution patterns of primates walking on arboreal supports, nor do we completely understand the mechanisms that regulate weight distribution in primates. We collected vertical peak force data for seven species of primates walking quadrupedally on instrumented terrestrial and arboreal supports. Our results show that, when walking on arboreal vs. terrestrial substrates, primates generally have lower vertical peak forces on both limbs but the difference is most extreme for the forelimb. We found that force reduction occurs primarily by decreasing forelimb and, to a lesser extent, hindlimb stiffness. As a result, on arboreal supports, primates experience significantly greater functional differentiation of the forelimb and hindlimb than on the ground. These data support long-standing theories that arboreal locomotion was a critical factor in the differentiation of the forelimbs and hindlimbs in primates. This change in functional role of the forelimb may have played a critical role in the origin of primates and facilitated the evolution of more specialized locomotor behaviors.

Animals↗
PubMed2006

Visual influences on primate encephalization.

Primates differ from most other mammals in having relatively large brains. As a result, numerous comparative studies have attempted to identify the selective variables influencing primate encephalization. However, none have examined the effect of the total amount of visual input on relative brain size. According to Jerison's principle of proper mass, functional areas of the brain devoted primarily to processing visual information should exhibit increases in size when the amount of visual input to those areas increases. As a result, the total amount of visual input to the brain could exert a large influence on encephalization because visual areas comprise a large proportion of total brain mass in primates. The goal of this analysis is to test the expectation of a direct relationship between visual input and encephalization using optic foramen size and optic nerve size as proxies for total visual input. Data were collected for a large comparative sample of primates and carnivorans, and three primary analyses were undertaken. First, the relationship between relative proxies for visual input and relative endocranial volume were examined using partial correlations and phylogenetic comparative methods. Second, to examine the generality of the results derived for extant primates, a parallel series of partial correlation and comparative analyses were undertaken using data for carnivorans. Third, data for various Eocene and Oligocene primates were compared with those for living primates in order to determine whether the fossil taxa demonstrate a similar relationship between relative brain size and visual input. All three analyses confirm the expectations of proper mass and favor the conclusion that the amount of visual input has been a major influence on the evolution of relative brain size in both primates and carnivorans. Furthermore, this study suggests that differences in visual input may partly explain (1) the high encephalization of primates relative to the primitive eutherian condition, (2) the high encephalization of extant anthropoids relative to other primates, and (3) the very low encephalization of Eocene adapiforms.

Animals↗
PubMed1998

Molecular evolution of trichromacy in primates.

Although trichromacy in Old and New World primates is based on three visual pigments with spectral peaks in the violet (SW, shortwave), green (MW, middlewave) and yellow-green (LW, longwave) regions of the spectrum, the underlying genetic mechanisms differ. The SW pigment is encoded in both cases by an autosomal gene and, in Old World primates, the MW and LW pigments by separate genes on the X chromosome. In contrast, there is a single polymorphic X-linked gene in most New World primates with three alleles coding for spectrally distinct pigments. The one reported exception to this rule is the New World howler monkey that follows the Old World system of separate LW and MW genes. A comparison of gene sequences in these different genetic systems indicates that the duplication that gave rise to the separate MW and LW genes of Old World primates is more ancient than that in the howler monkey. In addition, the amino acid sequences of the two howler monkey pigments show similarities to the pigments encoded by the polymorphic gene of other New World primates. It would appear therefore that the howler monkey gene duplication arose after the split between New and Old World primates and was generated by an unequal crossover that placed two different forms of the New World polymorphic gene on to a single chromosome. In contrast, the lack of identity at variable sites within the New and Old World systems argues for the origin of the separate genes in Old World primates by the duplication of a single form of the gene followed by divergence to give spectrally distinct LW and MW pigments. In contrast, the similarity in amino acid variation across the tri-allelic system of New World primates indicates that this polymorphism had a single origin in New World primates. A striking feature of all these pigments is the use of a common set of substitutions at three amino acid sites to achieve the spectral shift from MW at around 530 nm to LW at around 560 nm. The separate origin of the trichromacy in New and Old World primates would indicate that the selection of these three sites is the result of convergent evolution, perhaps as a consequence of visual adaptation in both cases to foraging for yellow and orange fruits against a green foliage.

Alouatta↗
PubMed1986

The new world primates as animal models of glucocorticoid resistance.

Many New World primate species have greatly increased plasma cortisol concentrations, decreased plasma cortisol binding globulin capacity and affinity, marked resistance of the hypothalamic-pituitary-adrenal axis to suppression by dexamethasone, and no biological evidence of glucocorticoid excess. These primates also have high levels of circulating progesterone, estrogen, mineralocorticoid, androgen and vitamin D. The glucocorticoid target tissues that have been examined (circulating mononuclear lymphocytes and cultured skin fibroblasts) have normal concentrations of glucocorticoid receptors with decreased affinity for dexamethasone. Transformation of B-lymphocytes with the Epstein-Barr virus leads to glucocorticoid receptor induction that is less than that observed with cells from Old World primates. The receptor in these cells has a low affinity for dexamethasone. The low affinity leads to an increased loss of specific bound ligand during thermal activation. Meroreceptor generation is normal. The molecular weight of the receptor, determined by SDS-PAGE, is similar to that of Old World primates (approximately 92,000) and the activation pattern per se, examined in vitro by heating cytosol and performing phosphocellulose chromatography, appears similar to that of human controls. The ratios of nuclear to cytosolic hormone-receptor-complexes and of cytosolic activated to unactivated receptor complexes in intact cells are similar to Old World primates. Results from mixing studies do not support the hypothesis that a binding inhibitor(s) or a deficient cytosolic positive modifier(s) of binding underlies the findings in these primates. The New World primates, unlike men with the syndrome of primary cortisol resistance, have compensated for their condition with intra-adrenal and mineralocorticoid receptor adaptations. Thus, unlike Old World primates, cortisol in New World primates has only weak sodium-retaining potency because the aldosterone receptor has a low affinity for cortisol. The common element that would explain the apparent resistance to six steroid hormones in New World primates remains unknown.

Adrenal Glands↗
PubMed2004

Pulmonary angiography for the diagnosis of thromboembolic events in the non-human primate.

BACKGROUND: Evaluating possible thromboembolic events in the non-human primate has traditionally required euthanasia, significantly limiting the ability to conduct longitudinal studies. We hypothesized that pulmonary angiography could offer a safe, reproducible, and non-lethal means to assess for pulmonary embolus in the non-human primate. METHODS: Eleven rhesus primates were studied using standard pulmonary angiography techniques. Five animals studied had previously received humanized anti-CD154 antibodies (associated with thromboembolism risk) in the context of skin transplantation 2 years before the angiography study. Four primates were studied after receiving mouse anti-human CD154 antibody following allogeneic islet or skin transplantation. RESULTS: Angiography was successful in all primates. We observed no complications, and all animals promptly recovered from the procedure. Angiographic findings consistent with thromboembolism were demonstrated in the three primates actively receiving anti-CD154 antibody and in one primate that last received anti-CD154 nearly 2 years before the study. The study was normal in both the streptozotocin-induced diabetic control animals. Histopathology of the lungs confirmed thrombus in two of the four primates, but no thromboembolus was identified in the other two. The first had limited pathologic evaluation without fine slices, and in the second (treated 2 years before with a humanized anti-CD154), ascariasis was found in the area identified as abnormal by the angiogram. CONCLUSIONS: Minimally invasive pulmonary angiography is a safe, reproducible, and inexpensive method to assess possible thromboembolic events in the non-human primate. This method may allow for the longitudinal assessment of non-human primates given novel agents that may promote thromboembolism.

Angiography, Digital Subtraction↗
PubMed2005

Serological detection of adenoviruses in non-human primates maintained in a colony in Kenya.

BACKGROUND: Adenoviruses are known to cause several human diseases including acute febrile respiratory syndromes, epidemic conjunctivitis and gastroenteritis. These diseases associated with adenovirus infection affect adults and are usually more severe in infants and children. Forty-seven human adenoviruses serotypes have so far been identified adenovirus. The diversity of these viruses has delayed progress on vaccine development due to difficulties in identifying appropriate vaccine targets. To date, limited studies have been done to determine the prevalence of adenovirus infection in non-human primates with the goal of developing a non-human primate model that can be used to study the mechanisms of infection. OBJECTIVE: To determine the prevalence of enteric adenovirus infection in Kenyan non-human primates. DESIGN: A prospective study to investigate the prevalence of enteric andenovirus infection in captive non-human primates maintained in a colony. SETTING: Faecal samples were collected from monkeys trapped from different geographical areas of Kenya and also from the ones maintained in a colony at the Institute of Primate Research (IPR), Kenya. SUBJECTS: Ninety four faecal samples were collected from three species of non-human primates consisting of various ages and sex. Samples were collected from monkeys trapped from different geographical areas of Kenya and also from the ones maintained in a colony at the Institute of Primate Research (IPR), Kenya. All the faecal samples were screened for presence of adenoviruses using a commercial antigen-capture enzyme immunoassay (EIA) kit, this is an enzyme-linked immunosorbent assay (ELISA) kit designed for diagnosis of human enteric adenoviruses in stool samples. RESULTS: The highest prevalence of adenoviruses, detected by EIA kit, was in olive baboons (Papio anubis, 52.9%), followed by vervet monkeys (Cercopithecus aethiops, 48.9%) and the yellow baboons (Papio cynocephalus, 18.8%). Sub-grouping within each species (based on age and sex) indicated no significant differences (p > 0.05) in adenovirus infection signifying equal susceptibility. The prevalence of adenoviruses in vervet monkeys that were also Simian Immunodeficiency virus (SIV) seropositive was determined and shown to be 63.2%. CONCLUSION: The results of this study indicate that adenovirus infection is prevalent among non-human primates in Kenya. These findings suggest that cross species transmission in Kenyan non-human primates may be a common occurrence and there is a possibility of zoonotic transmission of adenoviruses. Furthermore, our results highlight the potential of using these non-human primates as models for testing safety and efficacy of candidate adenovirus vaccines prior to clinical trials in humans.

Adenoviridae↗
PubMed2005

Primate sociality in evolutionary context.

Much work has been done to further our understanding of the mechanisms that underlie the diversity of primate social organizations, but none has addressed the limits to that diversity or the question of what causes species to either form or not form social networks. The fact that all living primates typically live in social networks makes it highly likely that the last common ancestor of living primates already lived in social networks, and that sociality formed an integral part of the adaptive nature of primate origins. A characterization of primate sociality within the wider mammalian context is therefore essential to further our understanding of the adaptive nature of primate origins. Here we determine correlates of sociality and nonsociality in rodents as a model to infer causes of sociality in primates. We found sociality to be most strongly associated with large-bodied arboreal species that include a significant portion of fruit in their diet. Fruits and other plant products, such as flowers, seeds, and young leaves, are patchily distributed in time and space and are therefore difficult to find. These food resources are, however, predictable and dependable when their location is known. Hence, membership in a social unit can maximize food exploitation if information on feeding sites is shared. Whether sociality evolved in the primate stem lineage or whether it was already present earlier in the evolution of Euarchontoglires remains uncertain, although tentative evidence points to the former scenario. In either case, frugivory is likely to have played an important role in maintaining the presence of a social lifestyle throughout primate evolution.

Animals↗
PubMed2006

Forelimb and hindlimb forces in walking and galloping primates.

One trait that distinguishes the walking gaits of most primates from those of most mammalian nonprimates is the distribution of weight between the forelimbs and hindlimbs. Nonprimate mammals generally experience higher vertical peak substrate reaction forces on the forelimb than on the hindlimb. Primates, in contrast, generally experience higher vertical peak substrate reaction forces on the hindlimb than on the forelimb. It is currently unclear whether this unusual pattern of force distribution characterizes other primate gaits as well. The available kinetic data for galloping primates are limited and present an ambiguous picture about peak-force distribution among the limbs. The present study investigates whether the pattern of forelimb-to-hindlimb force distribution seen during walking in primates is also displayed during galloping. Six species of primates were video-recorded during walking and galloping across a runway or horizontal pole instrumented with a force-plate. The results show that while the force differences between forelimb and hindlimb are not significantly different from zero during galloping, the pattern of force distribution is generally the same during walking and galloping for most primate species. These patterns and statistical results are similar to data collected during walking on the ground. The pattern of limb differentiation exhibited by primates during walking and galloping stands in contrast to the pattern seen in most nonprimate mammals, in which forelimb forces are significantly higher. The data reported here and by Demes et al. ([1994] J. Hum. Evol. 26:353-374) suggest that a relative reduction of forelimb vertical peak forces is part of an overall difference in locomotor mechanics between most primates and most nonprimate mammals during both walking and galloping.

Animals↗
PubMed1981

Toward a molecular paleontology of primate genomes. I. The HindIII and EcoRI dimer families of alphoid DNAs.

Families of related, but nonidentical repetitive DNA sequences, termed the alphoid DNAs, have been identified and characterized in representative species from seven major primate Families. The sequences appear as old as the primate Order itself: they are found in a prosimian (lemur), in a New World monkey, and in all Old World primates examined, including man. The alphoid DNAs are uniquely primate sequences and they may represent the most abundant repetitive DNAs in the primate genome. - A classification scheme for two major families of alphoid DNAs is proposed that is based upon restriction enzyme analysis and Southern blotting with radioactive probes prepared from component alpha DNA (Maio, 1971) and from the human EcoRI dimer sequences (Manuelidis, 1976). The family of alphoid DNAs that hybridizes readily with component alpha is termed the HindIII family of alphoid DNAs. This family shows an almost universal distribution among present-day primates. The family of DNA sequences that hybridizes readily with the human EcoRI dimer probe is termed the EcoRI dimer family of alphoid DNAs. This family may be restricted to the great apes and man. The two probes permitted the discrimination of different, but related alphoid families in present-day primates. Multiple alphoid sequence families are found within the genomes of individual primates and the major primate taxa can be characterized by the representations of the various alphoid DNAs within their genomes. - An Appendix is presented (Brown et al., 1981) indicating that competition hybridization effects may influence the autoradiographic banding patterns, and hence, the interpretations of Southern filter-transfer hybridizations when dealing with related repetitive sequences such as the alphoid DNAs that are present in abundance in eukaryotic genomes.

Animals↗
PubMed1994

Baboon and cotton-top tamarin B2m cDNA sequences and the evolution of primate beta 2-microglobulin.

Nonhuman primates represent phylogenetic intermediates for studying the divergence of human and murine beta 2Ms. We report the nucleotide sequences of B2m cDNA clones from a baboon cell line, 26CB-1 (Papio hamadryas; primates: Cercopithecoidea), and a cotton-top tamarin cell line, 1605L (Saguinus oedipus; primates: Ceboidea). The baboon and tamarin B2m sequences indicate a very slow rate of B2m evolution in primates relative to that in murid rodents. Phenotypic evolution of beta 2M has also been very conservative in primates, with only 9-14 substitutions separating baboon or tamarin beta 2Ms from those of humans or orangutans. Analyses of silent and amino-acid-altering nucleotide substitutions provide evidence that negative selection has acted to limit variability in beta strands of primate beta 2Ms, while positive selection has promoted diversity in non-beta-strand regions of murine beta 2Ms. No evidence for the action of selection upon beta 2M residues that contact the class I heavy chain was found in primates or mice. The finding that different selective forces have operated upon primate and murine beta 2Ms suggests that beta 2M may have evolved to serve distinct functions in primates and mice.

Amino Acid Sequence↗
PubMed1997

Aspartate 171 is the major primate-specific determinant of human growth hormone. Engineering porcine growth hormone to activate the human receptor.

It has been known for more than 4 decades that only primate growth hormones are effective in primate species, but it is only with the availability of the 2.8 A structure of the human growth hormone (hGH).hGH-binding protein (hGHBP)2 complex that Souza and co-workers (Souza, S. C., Frick, G. P., Wang, X., Kopchick, J. J., Lobo, R. B., and Goodman, H. M. (1995) Proc. Natl. Acad. Sci. U. S. A. 92, 959-963) were able to provide evidence that Arg-43 on the primate receptor is responsible. Here we have examined systematically the interaction between Arg-43 (primate receptor) or Leu-43 (non-primate receptors) and their complementary hormone residues Asp-171 (primate GH) and His-170 (non-primate hormones) in a four-way comparison involving exchanges of histidine and aspartate and exchanges of arginine and leucine. BAF/B03 lines were created and characterized which stably expressed hGH receptor, R43L hGH receptor, rabbit GH receptor, and L43R rabbit GH receptor. These were examined for site 1 affinity, for the ability to bind intact cells, and for proliferative biopotency using hGH, D171H hGH, porcine GH, or H170D porcine GH. We find that the single interaction between Arg-43 and His-170/171 is sufficient to explain virtually all of the primate species specificity, and this is congruent with the crystal structure. Accordingly, for the first time we have been able to engineer a non-primate hormone to bind to and activate the human GH receptor.

Amino Acid Substitution↗