Showing papers on "Primate published in 1998"
Book•
21 Sep 1998
TL;DR: This new edition brings this coverage up to date with the latest fossil finds and most current research, and retains its grounding in the extant primate groups as the best way to understand the fossil trail and the evolution of these modern forms.
Abstract: Tables & Illustrations. Preface. Adaptation, Evolution, and Systematics. The Primate Body. Primate Lives. Prosimians. New World Anthropoids. Old World Monkeys. Apes and Humans. Primate Communities. Primate Adaptations. The Fossil Record. Primate Origins. Fossil Prosimians. Early Anthropoids. Fossil Platyrrhines. Fossil Apes. Fossil Old World Monkeys. Hominids, the Bipedal Primates. Patterns in Primate Evolution. Index.
1,599 citations
TL;DR: The results suggest that neurons are produced in the dentate gyrus of adult monkeys and that the rate of precursor cell proliferation can be affected by a stressful experience.
Abstract: Although granule cells continue to be added to the dentate gyrus of adult rats and tree shrews, this phenomenon has not been demonstrated in the dentate gyrus of adult primates. To determine whether neurons are produced in the dentate gyrus of adult primates, adult marmoset monkeys (Callithrix jacchus) were injected with BrdU and perfused 2 hr or 3 weeks later. BrdU is a thymidine analog that is incorporated into proliferating cells during S phase. A substantial number of cells in the dentate gyrus of adult monkeys incorporated BrdU and ≈80% of these cells had morphological characteristics of granule neurons and expressed a neuronal marker by the 3-week time point. Previous studies suggest that the proliferation of granule cell precursors in the adult dentate gyrus can be inhibited by stress in rats and tree shrews. To test whether an aversive experience has a similar effect on cell proliferation in the primate brain, adult marmoset monkeys were exposed to a resident-intruder model of stress. After 1 hr in this condition, the intruder monkeys were injected with BrdU and perfused 2 hr later. The number of proliferating cells in the dentate gyrus of the intruder monkeys was compared with that of unstressed control monkeys. We found that a single exposure to this stressful experience resulted in a significant reduction in the number of these proliferating cells. Our results suggest that neurons are produced in the dentate gyrus of adult monkeys and that the rate of precursor cell proliferation can be affected by a stressful experience.
1,354 citations
TL;DR: It is suggested that evolutionary modification of the duration and number of progenitor cell divisions contributed to both the expansion and laminar elaboration of the primate neocortex.
Abstract: The evolutionary expansion of neocortical size in mammals is particularly prominent in anthropoid primates (i.e., monkeys, apes, and humans) and reflects an increased number of cortical cells, yet the developmental basis for this increase remains undefined. Cortical cell production depends on the length of the cell-division cycle of progenitor cells during neurogenesis, which previously has been measured only in smaller-brained rodents. To investigate whether cortical expansion in primates reflects modification of cell-cycle kinetics, we determined cell-cycle length during neurogenesis in the proliferative cerebral ventricular zone of fetal rhesus monkeys, by using cumulative S-phase labeling with bromodeoxyuridine. Cell-cycle durations in monkeys were as much as 5 times longer than those reported in rodents. Nonetheless, substantially more total rounds of cell division elapsed during the prolonged neurogenetic period of the monkey cortex, providing a basis for increased cell production. Moreover, unlike the progressive slowing that occurs during cortical development in rodents, cell division accelerated during neurogenesis of the enlarged cortical layers in monkeys. These findings suggest that evolutionary modification of the duration and number of progenitor cell divisions contributed to both the expansion and laminar elaboration of the primate neocortex.
281 citations
TL;DR: A hepadnavirus with a host intermediate between humans and rodents is isolated from a woolly monkey that was suffering from fulminant hepatitis and a new animal model for evaluation of antiviral therapies for treating HBV chronic infections is established.
Abstract: Hepatitis B virus (HBV) infections are a major worldwide health problem with chronic infections leading to cirrhosis and liver cancer. Viruses related to human HBV have been isolated from birds and rodents, but despite efforts to find hepadnaviruses that infect species intermediate in evolution between rodents and humans, none have been described. We recently isolated a hepadnavirus from a woolly monkey (Lagothrix lagotricha) that was suffering from fulminant hepatitis. Phylogenetic analysis of the nucleotide sequences of the core and surface genes indicated that the virus was distinct from the human HBV family, and because it is basal (ancestral) to the human monophyletic group, it probably represents a progenitor of the human viruses. This virus was designated woolly monkey hepatitis B virus (WMHBV). Analysis of woolly monkey colonies at five zoos indicated that WMHBV infections occurred in most of the animals at the Louisville zoo but not at four other zoos in the United States. The host range of WMHBV was examined by inoculation of one chimpanzee and two black-handed spider monkeys (Ateles geoffroyi), the closest nonendangered relative of the woolly monkey. The data suggest that spider monkeys are susceptible to infection with WMHBV and that minimal replication was observed in a chimpanzee. Thus, we have isolated a hepadnavirus with a host intermediate between humans and rodents and establishes a new animal model for evaluation of antiviral therapies for treating HBV chronic infections.
209 citations
Book•
01 Dec 1998
TL;DR: Primates as predators and as prey an African forest the hunters chimpanzees as predators red colobus monkeys as prey before the attack confrontation the impact of predation why do chimpanzees hunt?
Abstract: Primates as predators and as prey an African forest the hunters chimpanzees as predators red colobus monkeys as prey before the attack confrontation the impact of predation why do chimpanzees hunt? predation and primate social systems conclusion appendices - additional data on predator-prey ecology.
167 citations
TL;DR: It is argued that many primate lineages exhibit dental, digestive, and/or sensory adaptations that aid in the exploitation of particular food types and that many lineages of flowering plants have evolved characteristics of fruits and seeds that facilitate seed dispersal represent evolutionary rather than more strictly defined coevolutionary relationships.
Abstract: In this paper, we evaluate patterns of fruit eating and seed dispersal in monkeys and apes and draw an important distinction between 1) the ecological consequences of primates as seed dispersers and 2) the evolutionary implications of primates on the seed and fruit traits of the plant species they exploit. In many forest communities, primates act as both seed predators and seed dispersers and are likely to have an important ecological impact on patterns of forest regeneration and tree species diversity. Evidence from Kibale National Park, Uganda, and Manu National Park, Peru, as well as several other South American sites indicates that monkeys and apes display a wide range of fruit-processing behaviors, including spitting seeds, dropping seeds, masticating seeds, and swallowing seeds. Differences in consumer body size, diet, ranging patterns, and oral and digestive morphology result in different patterns in the distance and distribution of seeds from the parent plant. In the case of South American monkeys, for example, despite their relatively small body size, platyrrhines were found to exploit larger fruits and swallow larger seeds on average than did Old World monkeys and apes of the Kibale forest. We found little evidence to support the existence of a coevolutionary relationship between a single or set of primate dispersers and the particular plant species they disperse. This is due to variability in the manner in which monkeys and apes select fruits and treat seeds, the fact that many species of primates and nonprimates exploit and disperse the same fruit species, and the fact that extremely high levels of postdispersal seed, seedling, and sapling mortality serve to dilute the influence that any primate species may have on the recruitment of the next generation of adult trees. It is apparent that many primate lineages exhibit dental, digestive, and/or sensory adaptations that aid in the exploitation of particular food types and that many lineages of flowering plants have evolved characteristics of fruits and seeds that facilitate seed dispersal. However, in light of currently available data, we argue that these represent evolutionary rather than more strictly defined coevolutionary relationships.
132 citations
TL;DR: A significant increase in fight-hand use was noted from the unimanual, quadrupedal, reaching task to the coordinated-bimanual task, with females exhibiting a greater right-hand preference than males and a significant effect of task complexity on strength in laterality was found.
Abstract: Hand preferences in 26 capuchin monkeys (Cebus apella) were examined in 2 reaching-forfood tasks under 2 postural conditions. In the 1st task (unimanual), monkeys were required to reach for food from both a quadrupedal and an upright posture. A right-hand bias was found for the upright but not for the quadrupedal condition. In the 2nd task (coordinated bimanual), monkeys were required to extract the food from a hanging Plexiglas tube from both a crouched and an upright posture. A right-hand bias was found for both conditions. A significant increase in fight-hand use was noted from the unimanual, quadrupedal, reaching task to the coordinated-bimanual task, with females exhibiting a greater right-hand preference than males. In addition, a significant effect of task complexity on strength in laterality was found. Results are discussed in the context of recent theories on primate laterality.
120 citations
TL;DR: Results from vegetational transects suggest that the larger‐bodied patas monkey can subsist on such a diet because gum and arthropods are relatively easily found in their habitat, thereby minimizing search time.
Abstract: A 17 month field study of unprovisioned patas monkeys (Erythrocebus patas pyrrhonotus) in Laikipia, Kenya, using both ad libitum and scan sampling techniques, revealed that the diet of patas monkeys consists primarily of gum of Acacia drepanolobium, arthropods (both free-living and concentrated in the swollen thorns of A. drepanolobium), and other animals. This type of diet is normally found only in smaller-bodied primates. Results from vegetational transects suggest that the larger-bodied patas monkey can subsist on such a diet because gum and arthropods are relatively easily found in their habitat, thereby minimizing search time. Patas monkeys also spend more time moving and less time feeding (while not moving) than other Old World primates. The characteristic long limbs of patas may have evolved in response to feeding on small, nonusurpable, and widely distributed foods, in which access to foods is maximized while time and energy spent in terrestrial travel between food sites are minimized.
115 citations
TL;DR: The demographic systems (mortality and fertility estimates) for four broad groups of primates and their corresponding characteristics are presented and discussed and it is implied that the Pan traglodyte demography was probably evolutionarily derived from the general primate pattern.
Abstract: ▪ Abstract This chapter reviews the current state of knowledge concerning the demography of primates. It compiles demographic systems (mortality and fertility estimates) for four broad grades of primates: New World monkeys, Old World monkeys, chimpanzees, and humans. The characteristics of each system, including its demographic stability, are presented and discussed. The environmentally induced variation in human and nonhuman primate vital rates are explored whenever possible. Findings include (a) that more data are needed particularly with respect to nonhuman primate fertility, (b) that human demographic systems are the least stable, and (c) that Pan troglodytes demography is probably evolutionarily derived from the general primate pattern.
111 citations
TL;DR: It is suggested that these data provide further evidence of a network capable of eliciting rhythmic alternating activity resembling locomotion in the primate spinal cord, which seems to be more difficult to activate pharmacologically in those conditions than in other mammals.
Abstract: The existence of a spinal network capable of generating rhythmic alternating activity resembling locomotion still has not been firmly established in primates, including man, although evidence for one is accumulating. The present study investigated whether it is possible to activate such a network by administration of a variety of pharmacological agents to acutely spinalized marmoset monkeys (Callithrix jacchus) in the absence of phasic afferent input to the spinal cord. Fourteen marmoset monkeys were decerebrated, spinalized, and paralyzed. The nerves supplying both hindlimbs were cut and recorded from. In 5 monkeys the effect of electrical stimulation of the brainstem was investigated before spinalization. In 3 of these monkeys, rhythmic activity alternating between extensors and flexor nerves was seen. In the 2 other monkeys only synchronized activity was elicited. In acutely spinalized monkeys, administration of l-3,4-dihydroxyphenylalanine (l-dopa; 3–4 h after treatment with nialamide) failed to evoke any rhythmic alternating activity. In contrast, administration of clonidine elicited alternating activity in all of 8 monkeys tested. In 4 of these monkeys, the activity was restricted to alternation between ipsilateral and contralateral flexor nerves, whereas alternating activity between ipsilateral flexors and extensors was also seen in the other 4 monkeys. Administration of excitatory amino acids (NMDA or NMA) also elicited rhythmic alternating activity in 7 of 10 spinalized monkeys. In 4, rhythmic alternating activity was seen between extensors and flexors on one limb as well as between ipsilateral and contralateral flexors. In 3 monkeys NMDA/NMA produced alternation between extensors and flexors of one limb without alternation between the ipsilateral and contralateral sides. Administration of noradrenaline failed to elicit any rhythmic activity, but rather completely depressed already existing activity. Administration of serotonin (5-HT) was ineffective in facilitating alternating activity in 6 of 8 monkeys and was facilitatory to rhythmic activity in the other 2. We suggest that these data provide further evidence of a network capable of eliciting rhythmic alternating activity resembling locomotion in the primate spinal cord. The network, however, seems to be more difficult to activate pharmacologically in those conditions than in other mammals. This may especially be the case in higher primates, including man.
109 citations
TL;DR: Studies carried out over the past two decades show that many platyrrhine (New World) monkeys have polymorphic color vision, which results from the sorting of allelic versions of X-chromosome cone opsin genes at a single gene site, yielding a mixture of dichromatic and trichromatic phenotypes in the population.
01 Jan 1998
TL;DR: For over a century it has been known that primates have highly mobile grasping forelimbs with the supportive functions shifted more strongly to the hindlimbs, unlike most mammals where all four limbs share a fairly equal role in weight support.
Abstract: For over a century it has been known that primates have highly mobile grasping forelimbs with the supportive functions shifted more strongly to the hindlimbs, unlike most mammals where all four limbs share a fairly equal role in weight support. Darwin (1871) was the first to recognize this distinction between forelimb and hindlimbs and to articulate its evolutionary significance. Since that point many researchers have developed theories of primate locomotor evolution that suggest that the amount of compressive weight support experienced by the forelimb of primates was gradually reduced thus facilitating the use of the forelimb in tension and then allowing its complete removal from locomotion in humans (Wood Jones, 1926; Le Gros Clark, 1959; Napier and Davis, 1959; Napier, 1967; Stern, 1976; Ripley, 1979; Reynolds, 1981, 1985a,b; Cant, 1988; Rose, 1991). Fundamental to this scenario is the belief that the change in the role of the primate forelimb is directly related to adaptations to arboreal quadrupedalism by primates.
TL;DR: In this article, the authors compared the distribution of three calcium-binding protein-immunoreactive (CaBP-IMM) neuronal populations (calretininin, calbindin- and parvalbumin-immuneactive) in the visual and auditory systems in two mammalian species, the aquatic toothed whale Tursiops truncatus and the terrestrial macaque macaque.
TL;DR: It is suggested that chronic unpredictable psychological stress during pregnancy has long-lasting effects on noradrenergic and dopaminergic activity and behavior in the offspring of gestationally stressed primate mothers.
Abstract: In this study, we assessed behavioral responses to social separation at 8 months of age and cerebrospinal fluid (CSF) concentrations of biogenic amines and metabolites at 8 and 18 months of age in 12 rhesus monkeys derived from either stressed or undisturbed pregnancies. Compared to controls from undisturbed pregnancies, prenatal stress-derived monkeys had higher concentrations of 3-methoxy-4-hydroxyphenylglycol (MHPG), and 3,4-dihydroxyphenylacetic acid in CSF than controls. Norepinephrine and MHPG response to stress were both correlated between 8 and 18 months of age. There were few group differences in behavior during social separation; however, several behavioral differences between groups were found when monkeys were reunited with cage mates. Prenatally stressed monkeys spent more time clinging to their surrogates and exploring (including eating and drinking), while controls showed more locomotion and social play with their cage mates. Collectively, our findings suggest that chronic unpredictable psychological stress during pregnancy has long-lasting effects on noradrenergic and dopaminergic activity and behavior in the offspring of gestationally stressed primate mothers.
TL;DR: Comparison of DNA sequences with those of humans and three species of New World primate suggest a recent and independent acquisition of a second M/L gene locus in the howler.
TL;DR: The consistencies in the pattern of subcortical projections across prosimian primates, New World monkeys, and Old World monkeys support the concept that DM is a visual area common to all primates and provide further evidence for proposed subdivisions of the inferior pulvinar.
Abstract: The dorsomedial visual area (DM) of owl monkeys is a cortical area that has been described recently in a range of primate species. To study the thalamic connections of this area, injections of several distinguishable neuroanatomical tracers were placed into DM in galagos, owl monkeys, squirrel monkeys, and macaque monkeys. The distribution of label was remarkably consistent across these diverse primate species. Labeled connections were densest within the pulvinar complex. Both the lateral and inferior divisions of the pulvinar, but not the medial division, had connections with DM. Within the inferior pulvinar of monkeys, central lateral and central medial nuclei had dense connections, and the medial and posterior nuclei had sparse connections with DM. Sparser connections were revealed in the lateral geniculate nucleus and the nucleus limitans. Anterograde label was also found in the superior colliculus. The consistencies in the pattern of subcortical projections across prosimian primates, New World monkeys, and Old World monkeys support the concept that DM is a visual area common to all primates. In addition, these results provide further evidence for proposed subdivisions of the inferior pulvinar.
Book•
01 Jan 1998
TL;DR: The Skull, Teeth, Diet, and Digestion; The Brain and Special Senses; Growth and Development; Social Groups and Primate Behavior; Fossil Primates; Primate Conservation.
Abstract: ForewordPrefaceAcknowlegments1) Monkeys and Apes in History2) Classification and Distribution in Living Primates3) Blood Groups, Chromosomes, and DNA4) The Skull5) Teeth, Diet, and Digestion6) The Brain and Special Senses7) The Skeleton and Locomotion8) Growth and Development9) Social Groups and Primate Behavior10) Fossil Primates11) Primate ConservationGlossaryBibliographyIndex
TL;DR: Like found in humans, chimpanzee and rhesus macaque populations originating from different geographic backgrounds appear to be characterized by the presence of a few dominant Mhc-DPB1 alleles.
TL;DR: The ancestral HSA21 was formed after the divergence between platyrrhines and catarrhines and before the emergence of Cercopithecidae, which exposed the human and Pongidae ancestry to trisomy 21 for a period of 30-50 million years.
Abstract: Great apes (Pongidae) possess a chromosome similar to human chromosome 21 (HSA21), whose trisomy was described in both chimpanzee and orangutan. Having studied more than 200 mammalian species by chromosome banding techniques and reconstructed Primates phylogeny, we reinvestigated, using fluorescence in situ hybridization, primate and non-primate mammals that we considered to possess a karyotype representative of their taxonomic group. DNA sequences from HSA21 and human chromosome 3 (HSA3) are synthenic and form a large and similar chromosome in species from distinct orders, such as Primates, Carnivora, Artiodactyla and Scandentia. In Primates, this syntheny was maintained in lemurs and was disrupted by a fission in Old World monkeys (catarrhines). Another fission occurred in New World monkeys (platyrrhines), conserving a syntheny between HSA21 and a very short segment of HSA3 DNA sequences. Thus, the ancestral HSA21 was formed after the divergence between platyrrhines and catarrhines and before the emergence of Cercopithecidae. This exposed the human and Pongidae ancestry to trisomy 21 for a period of 30-50 million years, while, in other catarrhines, the equivalent of HSA21 was further involved in various translocations forming large chromosomes whose aneuploidy, very probably incompatible with life, protected them against trisomy 21.
TL;DR: A comparison between young and adult Microcebus murinus, a prosimian, and Old World monkeys (Macaca mulatta and Papio hamadryas) is presented, suggesting that astroglial interlaminar processes underwent an early expression within the primate order, with increasing presence in more recent primate species.
Abstract: Previous observations have shown that astrocytes with interlaminar processes are present in the cerebral cortex of humans and New and Old World monkeys, but not in the rodent. The present report furthers the analysis of possible evolutionary aspects regarding the expression of such astroglial features. A comparison between young and adult Microcebus murinus, a prosimian, and Old World monkeys (Macaca mulatta and Papio hamadryas) is presented. Brain samples were processed for glial fibrillary acidic protein (GFAP), vimentin, MAP2 and SMI 311 immunocytochemistry, using different procedures. The cerebral cortex of adult Microcebus showed the presence of long astroglial processes, albeit reduced in number and length with respect to those observed in Old World monkeys. Macaca and Papio showed dense packing of such processes extending in most cortical regions to a depth of approximately 700 micrometers. Based on double immunolabelling for GFAP and MAP 2 antigens, the location and extent of these processes was shown to overlap with areas traversed by bundles and individual apical dendrites. Aged Old World specimens depicted an increased thickness of terminal portions of interlaminar processes, with increased morphological alterations. Comparisons made between the average thickness of the ”brush” composed of interlaminar processes and the thickness of lamina I among the species analyzed disclosed an absence of relationship between them. This suggests that interlaminar processes do not represent cellular adaptations to the increase in thickness in superficial cortical laminae, but rather to some other evolutionary pressure. Since astroglial interlaminar processes are already present in a prosimian, although in a comparatively reduced manner, it is suggested that such processes underwent an early expression within the primate order, with increasing presence in more recent primate species.
TL;DR: Differences in attraction to novel objects were inversely related to age, and investigatory behavior appeared subdued as compared to other primate species.
Abstract: Adult titi monkeys react to novelty more strongly and cautiously than other New World primates. Developmental changes in responsiveness were assessed by presenting complex novel objects to family groups consisting of 11 male-female pairs and their adult (31–33 months), subadult (20–23 months), and juvenile offspring (10–16 months). Food and a simple block were included as control conditions. Differences in attraction to novel objects were inversely related to age. Juveniles approached more objects, more quickly, and spent more time near them than older subjects. Parents, the least responsive age-group, seemed more indifferent than cautious. Age-effects were smaller with the block, and negligible with food. Even in the most responsive age-group, investigatory behavior appeared subdued as compared to other primate species.
TL;DR: The nucleotide sequence of this region of the D4DR gene is determined in several species of prosimians and the tree shrew, suggesting that the ancestral primate presumably had one 48-bp unit, and duplication of the unit occurred at the stage of Prosimians.
Abstract: Human D4 dopamine receptor (D4DR) is polymorphic in terms of the repeat, numbers of the 48-base pairs (bp) sequence located in the third cytoplasmic loop of the receptor. The repeated sequence and its polymorphism in D4DR genes have also been identified in higher non-human primates, suggesting that the structure of D4DR has been maintained during primate evolution. To clarify the origin and divergence of the polymorphism in the D4DR gene, we determined the nucleotide sequence of this region of the D4DR gene in several species of prosimians and the tree shrew, a species which is closely related to primates. Prosimians except the tarsier had one or two unit(s) of the 48-bp sequence, and conserved sequences were recognized in most of the units of the prosimians. The tree shrew had only one unit of the 48-bp sequence, and its sequence was 71–75% identical to those of the nuits of galago, loris, and lemur. These findings suggest that the ancestral primate presumably had one 48-bp unit, and duplication of the unit occurred at the stage of prosimians. Tarsiers appeared to be distinct from other prosimians and simians because of the high repeat numbers of units and their sequences.
TL;DR: Evidence is provided for absence of cognitive impairment in monkeys exposed developmentally to methylmercury and on a series of tasks assessing central processing speed, which is highly correlated with intelligence in humans.
Book•
01 Jan 1998
TL;DR: In conclusion: Social Psychology and Primates, Intentionality, Deception and Social Intelligence, and Sexuality in Monkeys and Apes.
Abstract: Introduction: Social Psychology and Primates. Intentionality, Deception and Social Intelligence. Primate Communication and Social Psychology. Facial Expressions. Gestures, Postures and Touch. Vocal Signals: Apes. Vocal Signals: Monkeys. Tactics and Social Devices. Social Exchange and Grooming Partnerships. Sexuality in Monkeys and Apes. Dominance and Social Relationships. Primate Studies and Social Psychology. Appendices.
TL;DR: By a comparative study of the putative receptor recognition sites postulated for each type of receptor, it is inferred that the Callitrichidae (marmosets and tamarins) have retained the most primitive sweetness receptor among primates.
Abstract: Primates have stimulated more interest than any other group as humans are ranked in this same mammalian order. Gustatory responses of human and nonhuman primates have already been compared for compounds such as monosaccharides, oligosaccharides, polyols, amino acids, dipeptides, proteins, dihydrochalcones, sulfamates, saccharin, acesulfame, diterpenes or urea derivatives, all known to be sweet in man. But no rational comparison in primates has been attempted. Using a structure-activity relationship study in primates, it is now possible to classify the primate sweetness receptors into four types according to the behavioral responses observed from various selected compounds sweet in humans. The four types are represented by (1) the Callitrichidae and (2) the Cebidae, both from the infraorder Platyrrhini (New World monkeys), (3) the Lemuridae and Lorisidae, from the suborder Prosimii (prosimians), and (4) the Cercopithecidae (Old World monkeys), Hylobatidae (lesser apes), Pongidae (great apes), and Hominidae (humans) from the infraorder Catarrhini (Old World simians). By a comparative study of the putative receptor recognition sites postulated for each type of receptor, it is inferred that the Callitrichidae (marmosets and tamarins) have retained the most primitive sweetness receptor among primates. As we believe that the evolution of the sweetness receptor is a key factor involved in the raising of nonhuman primates from a ‘primitive grade’ towards a more ‘advanced’ or ‘simian grade,’ the possible phylogenetic implications of these findings will be discussed.
TL;DR: This work uses comparative analyses of relative primate brain part volumes to determine whether tarsius should be classified as a Haplorhine and shows that, for each of seven brain components whose relative size discriminates unequivocally between Strepsirhines and Hapl orhines, the tarsiers fall in the HaplOrhine distribution.
Abstract: The taxonomic position ofTarsius has been a topic of some debate. Recent molecular and anatomical studies have shoen that tarsiers share a number of derived traits with Anthropoids. These include aspects of their reporductive biology and aspects of their olfactory and visual systems. It has, therefore, been suggested that, despite a number of convergences with strepsirhine primates, tarsiers should be classified with the Anthropoid primates. We use comparative analyses of relative primate brain part volumes to determine whetherTarsius should be classified as a Haplorhine. We show that, for each of seven brain components whose relative size discriminates unequivocally between Strepsirhines and Haplorhines, the tarsiers fall in the Haplorhine distribution. These results confirm their classification with the Haplorhines.
TL;DR: A synthesis of data from both fossil analyses and comparisons of DNAs obtained from living apes and monkeys suggests that the last common ancestor of the living great apes was instead an unknown ape from Europe or Asia that migrated into Africa 10 million years ago.
Abstract: PRIMATE EVOLUTIONWriting in the 30 July/15 August issue of Current Biology , a pair of researchers make a controversial claim about the identity of the last common ancestor of the living great apes. Most paleontologists currently think that the ancestor was an extinct African ape. But based on a synthesis of data from both fossil analyses and comparisons of DNAs obtained from living apes and monkeys, the researchers propose that it was instead an unknown ape from Europe or Asia that migrated into Africa 10 million years ago.
TL;DR: Data obtained from Southern blot analysis of the gamma genes in several primate species suggest that a single IgG gene was present in the ancestor of primates and was later duplicated several times during primate evolution.
Abstract: Four Immunoglobulin gamma heavy chain isotypes are present in humans; the true phylogenetic relationship between the genes are not known because of the complex concerted evolution of the Ig multigene locus. Here we present data obtained from Southern blot analysis of the gamma genes in several primate species including prosimians (Lemur catta), New World Monkeys (Saguinus oedipus) and Old World Monkeys (Cercopitecus aethiops andMacaca fascicularis). Our data show the presence of a single IgG gene inLemur and probably inS.l oedipus, and of multiple genes in the two Cercopithecinae. These findings suggest that a single IgG gene was present in the ancestor of primates: we suppose that this IgG gene was later duplicated several times during primate evolution.