Genetic divergence of orangutan subspecies (Pongo pygmaeus)

Microsatellites and mitochondrial DNA sequences were studied for the two subspecies of orangutans (Pongo pygmaeus), which are located in Borneo (P. p, pygmaeus) and Sumatra (P. p. abelii), respectively. Both subspecies possess marked genetic diversity. Ge

Feature Versus Spatial Strategies by Orangutans (Pongo abelii) and Human Children (Homo sapiens) in a Cross-Dimensional Task

Despite the fact that photographic stimuli are used across experimental contexts with both human and nonhuman subjects, the nature of individuals' perceptions of these stimuli is still not well understood. In the present experiments, we tested whether three orangutans and 36 human children could use photographic information presented on a computer screen to solve a perceptually corresponding problem in the physical domain. Furthermore, we tested the cues that aided in this process by pitting featural information against spatial position in a series of probe trials. We found that many of the children and one orangutan were successfully able to use the information cross-dimensionally; however, the other two orangutans and almost a quarter of the children failed to acquire the task. Species differences emerged with respect to ease of task acquisition. More striking, however, were the differences in cues that participants used to solve the task: Whereas the orangutan used a spatial strategy, the majority of children used a feature one. Possible reasons for these differences are discussed from both evolutionary and developmental perspectives. The novel results found here underscore the need for further testing in this area to design appropriate experimental paradigms in future comparative research settings.

Swimming and diving behavior in apes (Pan troglodytes and Pongo pygmaeus): first documented report

Extant hominoids, including humans, are well known for their inability to swim instinctively. We report swimming and diving in two captive apes using visual observation and video recording. One common chimpanzee and one orangutan swam repeatedly at the water surface over a distance of 2-6 m; both individuals submerged repeatedly. We show that apes are able to overcome their negative buoyancy by deliberate swimming, using movements which deviate from the doggy-paddle pattern observed in other primates. We suggest that apes' poor swimming ability is due to behavioral, anatomical, and neuromotor changes related to an adaptation to arboreal life in their early phylogeny. This strong adaptive focus on arboreal life led to decreased opportunities to interact with water bodies and consequently to a reduction of selective pressure to maintain innate swimming behavior. As the doggy paddle is associated with quadrupedal walking, a deviation from terrestrial locomotion might have interfered with the fixed rhythmic action patterns responsible for innate swimming.

Do dogs (canis familiaris) understand invisible displacement?

Domestic dogs (Canis familiaris) perform above chance on invisible displacement tasks despite showing few other signs of possessing the necessary representational abilities. Four experiments investigated how dogs find an object that has been hidden in 1 of 3 opaque boxes. Dogs passed the task under a variety of control conditions, but only if the device used to displace the object ended up adjacent to the target box after the displacement. These results suggest that the search behavior of dogs was guided by simple associative rules rather than mental representation of the object's past trajectory. In contrast, Experiment 5 found that on the same task, 18- and 24-month-old children showed no disparity between trials in which the displacement device was adjacent or nonadjacent to the target box.

Do chimpanzees (Pan troglodytes) understand single invisible displacement?

Previous research suggests that chimpanzees understand single invisible displacement. However, this Piagetian task may be solvable through the use of simple search strategies rather than through mentally representing the past trajectory of an object. Four control conditions were thus administered to two chimpanzees in order to separate associative search strategies from performance based on mental representation. Strategies involving experimenter cue-use, search at the last or first box visited by the displacement device, and search at boxes adjacent to the displacement device were systematically controlled for. Chimpanzees showed no indications of utilizing these simple strategies, suggesting that their capacity to mentally represent single invisible displacements is comparable to that of 18-24-month-old children.

Do chimpanzees (Pan troglodytes) and 2-year-old children (Homo sapiens) understand double invisible displacement?

Chimpanzees (Pan troglodytes) and young children (Homo sapiens) have difficulty with double invisible displacements in which an object is hidden in two nonadjacent boxes in a linear array. Experiment 1 eliminated the possibility that chimpanzees' previous poor performance was due to the hiding direction of the displacement device. As in Call (2001), subjects failed double nonadjacent displacements, showing a tendency to select adjacent boxes. In Experiments 2 and 3, chimpanzees and 24-month-old children were tested on a new adaptation of the task in which four hiding boxes were presented in a diamond-shaped array on a vertical plane. Both species performed above chance on double invisible displacements using this format, suggesting that previous poor performance was due to a response bias or inhibition problem rather than a fundamental limitation in representational capacity.

Sequence evolution of the CCR5 chemokine receptor gene in primates

The chemokine receptor CCR5 can serve as a coreceptor for M-tropic HIV-1 infection and both M-tropic and T-tropic SIV infection. We sequenced the entire CCR5 gene from 10 nonhuman primates: Pongo pygmaeus, Hylobates leucogenys, Trachypithecus francoisi, Trachypithecus phayrei, Pygathrix nemaeus, Rhinopithecus roxellanae, Rhinopithecus bieti, Rhinopithecus avunculus, Macaca assamensis, and Macaca arctoides. When compared with CCR5 sequences from humans and other primates, our results demonstrate that:(1) nucleotide and amino acid sequences of CCR5 among primates are highly homologous, with variations slightly concentrated on the amino and carboxyl termini; and (2) site Asp13, which is critical for CD4-independent binding of SIV gp120 to Macaca mulatta CCR5, was also present in all other nonhuman primates tested here, suggesting that those nonhuman primate CCR5s might also bind SIV gp120 without the presence of CD4. The topologies of CCR5 gene trees constructed here conflict with the putative opinion that the snub-nosed langurs compose a monophyletic group, suggesting that the CCR5 gene may not be a good genetic marker for low-level phylogenetic analysis. The evolutionary rate of CCR5 was calculated, and our results suggest a slowdown in primates after they diverged from rodents. The synonymous mutation rate of CCR5 in primates is constant, about 1.1 x 10(-9) synonymous mutations per site per year. Comparisons of K-a and K-s suggest that the CCR5 genes have undergone negative or purifying selection. K-a/K-s ratios from cercopithecines and colobines are significantly different, implying that selective pressures have played different roles in the two lineages.

Structure analysis of CCR5 from human and primates

It is well known that the chemokine receptor CCR5 plays very important roles in HIV-1 virus infection. A three-dimensional molecular model of human CCR5 was generated by SYBYL, a distance geometry-based homologous modeling package, using the corresponding transmembrane domain of bacteriorhodopsin as the template. On the basis of human CCR5 model, we also built 18 3D molecular models of CCR5 in primates from Pongo pygmaeus, Pygathrix nemaeus, Macaca assameniss, Trachy-pithecus phayrei, T. francoisi, M. arotoides, Rhinopithecus roxellance, R, bieti, R. avunculus, Hylobates leucogenys, Pan troglodytes, Gorilla gorilla, Cercopithecus aethiops 1, C. aethiops 2, Papio hamadryas M. mulatta, M. fascicularis and M. nemestrina. Structural analyses and statistics results suggested that the main-chains of the primate CCR5 were similar to that of the human CCR5 and that the fit-RMS deviation values of these primate CCR5 were less than 0.1 Angstrom. Moreover, the structures of these CCR5 proteins, except those of the African green monkey 1 (C.aet1), do not have a remarkable difference. It is proved that the 14th residue is possibly very important in the inhibition infections by M-tropic HIV-1, and it is also demonstrated that the 13th residue of human CCR5 was changed from asparagine into aspartic acid in all these primates. It means that the primate CCR5 no longer depend on CD4 for efficient entry, but human CCR5 may have evolved subsequently due to the use of CD4 as a receptor, allowing the high-affinity chemokine receptor-binding site of HIV to be sequestered from host immune surveillance. (C) 2000 Elsevier Science B.V. All rights reserved.

猕猴白化病分子机制和灵长类的分子进化研究

酪氨酸酶是黑色素合成当中的关键酶。人酪氨酸酶基因包括5个外显子，在染色体11q14-q21位置上占据了约50kb长的区域。对人类眼皮肤型白化病（Oculocutaneous albinism, OCA)的许多研究表明，该病主要是由于酪氨酸酶基因的突变引起的。昆明动物研究所白化猴研究小组数十年来一直从事白化猕猴的培育和研究工作，目前饲养着2只白化猕猴和它们的后代，这提供了我们研究猕猴白化分子机制目的条件。为了弄清猕猴白化病的分子机制，我们根据人酪氨酸酶基因序列设计了5对PCR引物扩增相应的5个外显子，序列分析表明，白化猕猴珍珍酪氨酸酶基因第184个密码子第2位置（外显子1的核苷酸位置551）处发生一个C→A的无义突变，使编码丝氨酸（Ser)的密码子变成了一个终止密码，这样后面1038bp的核苷酸片段（346个氨基酸残基）被截断，导致酪氨酸酶翻译不完全，迄今为止，并没有发现合成黑色素的第二条生化途径，因此由于该酶不能行使正常功能而将导致黑色素不能正常表达。这可能是导致该例猕猴白化病的原因。为了解酪氨酸酶基因序列变异的规律及其与功能的关系，探讨该基因作为系统发育研究中遗传标记的有效性，我们测定了黑猩猩（Pan troglodytes)、倭黑猩猩（Pan paniscus)、大猩猩（Gorilla gorilla)、猩猩(Pongo pygmaeus)、长臂猿（Hylobates lar)、食蟹猴（Macaca fascicularis)、狒狒（Simia cynocephalus)、猕猴（Macaca mulatta)、熊猴（Macaca assamensis)、菲氏叶猴（Presbytis p. crepusculus)、白臀叶猴（Pygathrix nemaeus)、滇金丝猴（Rhinopithecus r. bieti）和蛛猴（Ateles paniscus)13个灵长类中代表种的酪氨酸酶基因全部5个外显子的DNA序列。基于这些序列，用简约法构建了分子系统树。结果表明，人猿超科与旧大陆猴各自形成一单系群。人猿超科各物种和旧大陆猴有明显分化，人与大猩猩的关系比人与黑猩猩的关系近。酪氨酸酶基因在解决灵长类系统发育关系上是一个较有用的基因。为了进一步了解中国猕猴（Macaca mulatta)的亚种分化和不同地理群体间的基因流状况，我们测定了来自中云南、广西、福建、海南、浙江、河南、湖南、湖北、安徽、四川、贵州和越南猕猴共96只个体和一只外群食蟹猴的线粒体DNA控制区576bp的DNA序列，基于这些序列，运用距离法对中国恒河猴的分子进行和遗传多样性进行了分析，我们的研究结果显示，云南、四川和湖南猕猴群体与其它群体存在显著分析，海南群体内遗传多样性最低、四川、广西、浙江、福建和越南群体内遗传多样性较丰富。中国猕猴的分化可能存在三条路线。中国猕猴的遗传多样性较丰富。

Dust accumulation in the canopy: a potential cause of dental microwear in primates.

Dental microwear researchers consider exogenous grit or dust to be an important cause of microscopic wear on primate teeth. No study to date has examined the accumulation of such abrasives on foods eaten by primates in the forest. This investigation introduces a method to collect dust at various heights in the canopy. Results from dust collection studies conducted at the primate research stations at Ketambe in Indonesia, and Hacienda La Pacifica in Costa Rica indicate that 1) grit collects throughout the canopy in both open country and tropical rain forest environments; and 2) the sizes and concentrations of dust particles accumulated over a fixed period of time differ depending on site location and season of investigation. These results may hold important implications for the interpretation of microwear on primate teeth.

Dated co-occurrence of Homo erectus and Gigantopithecus from Tham Khuyen Cave, Vietnam.

Tham Khuyen Cave (Lang Son Province, northern Vietnam) is one of the more significant sites to yield fossil vertebrates in east Asia. During the mid-1960s, excavation in a suite of deposits produced important hominoid dental remains of middle Pleistocene age. We undertake more rigorous analyses of these sediments to understand the fluvial dynamics of Pleistocene cave infilling as they determine how skeletal elements accumulate within Tham Khuyen and other east Asian sites. Uranium/thorium series analysis of speleothems brackets the Pleistocene chronology for breaching, infilling, and exhuming the regional paleokarst. Clast analysis indicates sedimentary constituents, including hominoid teeth and cranial fragments accumulated from very short distances and under low fluvial energy. Electron spin resonance analysis of vertebrate tooth enamel and sediments shows that the main fossil-bearing suite (S1-S3) was deposited about 475 thousand years ago. Among the hominoid teeth excavated from S1-S3, some represent Homo erectus and Gigantopithecus blacki. Criteria are defined to differentiate these teeth from more numerous Pongo pygmaeus elements. The dated co-occurrence of Homo erectus and Gigantopithecus blacki at Tham Khuyen helps to establish the long co-existence of these two species throughout east Asia during the Early and Middle Pleistocene.

Mirror self-recognition in a gorilla (gorilla gorilla gorilla)

Psychologists have studied self-recognition in human infants as an indication of self-knowledge (Amsterdam, 1972) and the development of abstract thought processes. Gallup (1970) modified the mark test used in human infant work to examine if nonhuman primates showed similar evidence of mirror self-recognition. Chimpanzees (Pan troglodytes) and orangutans (Pongo pygmnaeus) pass the mirror self-recognition test with limited mirror training or exposure. Other species of primates, such as gorillas and monkeys, have not passed the mirror test, despite extensive mirror exposure and training (Gallup, 1979). This project examined a gorilla (G. gorilla gorilla) named Otto in the traditional mark test. Using the modified mark-test, there were more incidents of touching the marked area while Otto was in front of the mirror than when he was not in front of the mirror. These results indicated that Otto was able to show some evidence of selfawareness.

Mitochondrial control region and population genetic patterns of Nycticebus bengalensis and N-Pygmaeus

Bengal slow lorises (Nycticebus bengalensis) and pygmy slow lorises (Nycticebus pygmaeus) are nocturnal which creates difficulties to study them in the field. There is a scarcity of data on them and their population genetics are poorly understood. We sequ