Higher rate of evolution of X chromosome alpha-repeat DNA in human than in the great apes.

The rate of introduction of neutral mutations is lower in man than in other primates, including the chimpanzee. This species is generally regarded as our closest relative among the great apes. We present here an analysis of sequences of X chromosomal alphoid repetitive DNA from man and the great apes, which supports the closer relationship between man and chimpanzee and indicates a considerably increased rate of recombination in the human repeat DNA. These results indicate that the 'molecular clock' is running more quickly in man.     

Fluorescent heterochromatin staining in primate chromosomes

Recently, in addition to quinacrine staining, fluorochrome techniques have been developed which brilliantly stain other heterochromatic regions. Two of these staining techniques are Distamycin/DAPI (DA/DAPI) and D287/170. We stained the chromosomes of all species of great apes and 14 species of primates (48 individuals) using these three fluorochrome techniques. Only african apes and man show brilliant quinacrine staining while, man and all the great apes show brilliant DA/DAPI staining and only species belonging to the hominoidea (including the siamang) showed bright D287/170 staining. In the lower primates a medium level of DA/DAPI fluorescence was found in some species with large amount of pericentromeric heterochromatin. Brilliant DA/DAPI staining could represent a derived trait linking all great apes and humans, while D287/170 may link all hominoidea. Fluorochrome staining is believed to be correlated with some satellite DNA sequences. However, data available on the chromosome location of satellite DNAs in non-human primates were derived from buoyant density fractions resulting in cross hybridization and now are not considered reliable. Before making any correlation between fluorochrome staining and satellite DNAs in non human primates there is need of data onin situ hybridization with cloned DNA sequences on primate chromosomes. These data would help clarify the evolution and relationship of satellite DNAs and heterochromatin in primates.     

Origin of the human hand

A means of determining the phylogenetic implications of similarities between the hands of man and non-human primates is proposed. The only traits shared by man and non-human primates accepted as evidence of our ancestral hand structure and functions are those which are incompatible or out of keeping with current behavior of the human hand. They may be assumed to remain only as relics of adaptations to former habits of locomotion and feeding. The relics found through this analysis are all traits that are present in the apes (some of them only in African apes) and probably related to functions of the hand in suspension of the body, fist-walking, and knuckle-walking. The presence of these traits in man implies that human ancestors similarly used the hand to suspend the body in the trees and to support it on the back of the flexed fingers.     

Morphometric affinities of the human shoulder

To analyze differences between apes and monkeys and the affinities of man, we have studied the shoulder girdle of 327 specimens of anthropoid primates. The scapula, clavicle and humerus are viewed as an integrated functional complex on the basis of 18 measurements. Several varieties of multivariate analysis show that man is clearly closer to other hominoids than to the included monkey taxa (whether terrestrial or arboreal, Old World or New World). The marked shoulder differences between apes and monkeys and similarities between apes and man correlate with the muscular anatomy, which in hominoids allows the motions involved in their locomotion and feeding behavior. As the hominid-pongid correspondence in shoulder morphology is especially detailed regarding the functionally important joint surfaces, it is consistent with a fairly recent period of common ancestry and behavior. No hypothetical evolutionary pathway or ancestral form of the human shoulder need look far beyond the model afforded by extant pongids. In contrast with previous studies on the primate shoulder, these results agree with information accumulating from other systems—comparative anatomy, primate behavior, and molecular biology — in suggesting very close relationship between man and extant African pongids.     

The Skin of Nonhuman Primates

SYNOPSIS What distinguishes man from all other primates is hisarchaic hair cover Nearly all the details that make his skinunique aie traceable to this single fact In vatious degrees,allnonhuman primates have a good pelage,which is characterizedby some morphological and physiological similarities but oftendiffers even between closely relatedspecies It can be thickor thin,short or long woolly or shaggy, dense oi sparse, andit assumes many varied colors All primates have dermitoglyphicson their faction surfaces they are also present on the volarsurface of the tail of some New World monkeys ind on the knucklepads of chimpanzees and gonllas The epidermis is uniformly thinand has little undersculpture Every species of primate has epideimaland dermal melinocytes which are often relatively distinct fromall otheis Eccrine sweat glmds are found on the fnction surfacesof all species, but onlv the tiue piehensile tailed New Worldmonkeys andOld World monkeys and apes have them also in thehairy skin Although chimpanzees and gorillas have more ercunethan apocrine glands in their bodies, in neither do the sweatglands respond to heat stimulation as they do in man All primateshavenumerous apocrine glands in the hany skin, but only man,the chimpanzee, and gorilla have an axillaiy organ The OideiPrimates is large and heteiogeneous most species have some commoncutaneous featuies but the details in each are so distinct asto preclude generalizations     

Stride lengths and stride frequencies of primates

Stride lengths and stride frequencies of primates have been observed or collected from the literature. Data for Galago , various monkeys and apes, and man have been collected. The quadrupedal primates take longer strides, at any particular speed, than would be predicted for non-primates. When they gallop they use lower stride frequencies than non-primates of equal mass.     

Footfall patterns, stride length and speed of vertical climbing in spider monkeys (Ateles fusciceps robustus) and woolly monkeys (Lagothrix lagotricha)

Vertical climbing is central to theories surrounding the locomotor specialisations of large primates. In this paper, we present spatiotemporal gait parameters obtained from video recordings of captive spider monkeys (Ateles fusciceps robustus) and woolly monkeys (Lagothrix lagotricha) in semi-natural enclosures, with the aim of discovering the influence of body weight and differences in general locomotor behaviour on vertical climbing kinematics on various substrates. Results show that there are only few differences between gait parameters of climbing on thin trees, vertical and oblique ropes, while climbing on large-diameter trees differs considerably, reflecting the higher costs of locomotion on the latter. At the same speed, Ateles takes longer strides and the support phase takes a smaller percentage of cycle duration than in Lagothrix. Footfall patterns are more diverse in Ateles and include a higher proportion of ipsilateral limb coupling. Compared to other primates, the gait characteristics of vertical climbing of atelines most closely resemble those of African apes.     

An evolutionary conserved early replicating segment on the sex chromosomes of man and the great apes

Replication studies on prometaphase chromosomes of man, the chimpanzee, the pygmy chimpanzee, the gorilla, and the orangutan reveal great interspecific homologies between the autosomes. The early replicating X chromosomes clearly show a high degree of conservation of both the pattern and the time course of replication. An early replicating segment on the short arm of the X chromosomes of man (Xp22.3) which escapes inactivation can be found on the X chromosomes of the great apes as well. Furthermore, the most early replicating segment on the Y chromosomes of all species tested appears to be homologous to this segment on the X chromosomes. Therefore, these early replicating segments in the great apes may correspond to the pseudoautosomal segment proposed to exist in man. From further cytogenetic characterization of the Y chromosomes it is evident that structural alterations have resulted in an extreme divergence in both the euchromatic and heterochromatic parts. It is assumed, therefore, that, in contrast to the X chromosomes, the Y chromosomes have undergone a rapid evolution within the higher primates.     

Nucleotide sequences of immunoglobulin-epsilon pseudogenes in man and apes and their phylogenetic relationships

To understand the phylogenetic relationships between hominoids, the nucleotide sequences of immunoglobulin-epsilon processed pseudogenes from chimpanzee, gorilla and orangutan were determined. The basic structures of these processed pseudogenes agreed with their human counterpart. Although the degrees of nucleotide differences between man and the African apes had no statistical significance, all the analytical data examined supported the theory that chimpanzee is the closest relative of man. This result was consistent with that deduced by our recent qualitative study. Studies on the nucleotide sequences of globin genes have suggested that the molecular clock runs more slowly in hominoids than in non-hominoid primates. According to the present data, however, further retardation of the evolutionary rate was not observed in the human lineage. Assuming that orangutan diverged 14 million years ago and that the evolutionary rate between the orangutan lineage and the lineage leading to the other three species is constant, the divergence dates of chimpanzee and gorilla were estimated to be 4.9(+/- 0.9) and 5.9(+/- 0.9) million years ago, respectively.     

Intestinal microflora of monkeys, normal and in pathology, and its correction by preparations of live bacteria from human biocenosis (coli bacteria, bifikol and bifidum bacterin)

The study of the qualitative and quantitative composition of intestinal microflora in 15 anthropoid apes, 60 lower primates and 72 monkeys with clinically pronounced dysbacteriosis was made, which revealed the prevalence of microorganisms belonging to the genus Proteus, a decrease in the biological activity of normal Escherichia coli and in the content of bifido- and lactobacteria. The treatment of 39 rhesus and pig-tailed macaques with the preparations of live bacteria occurring in normal human microflora led to clinical convalescence and the normalization of the bacteriocenosis, while in 33 control animals no positive shifts in clinical and bacteriological data were observed. The essential similarity of the composition of intestinal microflora in higher and lower primates and in man makes it possible to use these animals as models for testing the effectiveness of new biological preparations and determines the expediency of using bacterial therapy for the treatment of monkeys at the period of acclimatization.     

A case of spontaneous acquisition of a human sound by an orangutan

The capacity of nonhuman primates to actively modify the acoustic structure of existing sounds or vocalizations in their repertoire appears limited. Several studies have reported population or community differences in the acoustical structure of nonhuman primate long distance calls and have suggested vocal learning as a mechanism for explaining such variation. In addition, recent studies on great apes have indicated that there are repertoire differences between populations. Some populations have sounds in their repertoire that others have not. These differences have also been suggested to be the result of vocal learning. On yet another level great apes can, after extensive human training, also learn some species atypical vocalizations. Here we show a new aspect of great ape vocal learning by providing data that an orangutan has spontaneously (without any training) acquired a human whistle and can modulate the duration and number of whistles to copy a human model. This might indicate that the learning capacities of great apes in the auditory domain might be more flexible than hitherto assumed. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Hoc alterum auditus organi ossiculum est: Ear Ossicles in Physical Anthropology

In spite of the importance of auditory ossicles in anthropological studies, very little attention has been paid to these bones, which are only rarely recovered in archaeological excavations and in osteological collections. In this paper, we attempt to review some studies that started in the 1960 from when we first collected and prepared ossicles from the early Egyptian osteological collection of Giovanni Marro in Turin (Italy). We attempt to delineate the potential of ear bones in the study of man. In a few cases, archaeological ossicles were discussed in connection with some forms of pathology. Other studies examined the phylogeny of primates based on auditory ossicles. The function of the ossicles is to transmit sound waves to the cochlear endolymph. The energy transmitted through the ossicles is conserved by the action of two levers, which convert the relatively wide and low-energy movements of the hammer into smaller high-energy movements of the stirrup. It is a matter of argument whether the different proportions of the ossicles may imply variations in auditory perception in primates, including man. While the hammer of modern humans and that of the great apes show similar absolute sizes, nevertheless, the ape manubrium is appreciably greater than that of man. This difference, combined with stirrup proportions, causes a strong “low-gear” effect in apes and, as a consequence, probably a different auditory acuity. Although only a few fossil Neanderthal auditory ossicles are known, it may be, nevertheless, of interest studying the ossicles from the viewpoint of vibration transfer impedance function. The methodology may also be appropriate to study the few Australopithecine ossicles that are known. It is a matter of question whether the ossicles may have a meaning in distinguishing human populations; nevertheless, at least a case of clear distinction between human population has been achieved as in the case of Antinoe Roman–Egyptians.     

An alternative paradigm for hominoid evolution

Biological clock data from protein sequences indicate times for the divergence of humans and African apes that are only 2–3 million years before the present and hence inconsistent with the generally accepted view ofAustralopithecus on the evolutionary line toHomo. This inconsistency has been reconciled for most investigators by postulating a slowing of the biological clock among higher primates. However, there is no independent evidence for such a slowing, and for a number of reasons a specific slowing is unlikely. Therefore, an alternative paradigm is considered here based on the hypothesis that the molecular clock data are correct. The main consequence of this hypothesis is the placement ofA. afarensis in a position ancestral to African apes. An argument in support of this alternative paradigm is formulated concerning the evolution of knuckle-walking in African apes from ancestors whose bipedalism was already well developed. Published data are cited, particularly concerning the structure of the wrist, which accommodate poorly the evolution of African apes from palmigrad-walking or brachiating ancestors resemblingProconsul africanus orPongo. These arguments suggest that an alternative paradigm of hominoid evolution placingA. afarensis ancestral toHomo, Gorilla, andPan warrants further consideration.     

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.     

Preterm birth without progesterone withdrawal in 15-hydroxyprostaglandin dehydrogenase hypomorphic mice

Parturition is a complex mammalian physiological process whose fundamental determinants have remained elusive. The increasing incidence of human preterm birth, a leading cause of infant mortality, highlights the importance of further understanding mechanisms regulating the timing of birth. Parturition is initiated in most nonprimate mammals, including mice, through a decrease in circulating progesterone caused by elevated prostaglandins. In humans, other higher primates, and guinea pigs, no consistent decrease in circulating progesterone occurs before the onset of labor. The divergence in endocrine control of labor initiation between most mammals compared with the great apes and guinea pigs gives rise to the question: how could a mechanism for the initiation of labor not requiring the withdrawal of progesterone evolve? Here, we genetically modulate prostaglandin signaling to determine the role of prostaglandin catabolism in the timing of birth. We find spontaneous preterm labor in the absence of progesterone withdrawal in 15-hydroxyprostaglandin dehydrogenase hypomorphic mice. The onset of labor in these hypomorphic mice is preceded by prematurely increased concentrations of prostaglandin E(2) and F(2alpha). Moreover, genetic crosses demonstrate a role for fetal genotype in birth timing. Together, these findings demonstrate a 15-hydroxyprostaglandin dehydrogenase-dependent shift in the physiology of murine parturition to one resembling the physiology of higher primates. Thus, endocrine control of labor has the capacity to plastically adapt to changes in genetically determined prostaglandin signals.     

Frequency and timing of scaphoid-centrale fusion in hominoids

Fusion between the os centrale and the scaphoid has played a central role in many functional and phylogenetic interpretations of hominoid evolution. In particular, scaphoid-centrale fusion shared among African apes and humans has been interpreted as an adaptation in knuckle-walkers, an exaptation in hominins, and has been offered as evidence for a knuckle-walking origin of bipedalism. However, discrepancies in the literature concerning the taxa in which this scaphoid-centrale fusion occurs, as well as the timing and/or frequency of this fusion, have confounded the significance of this trait. This study provides an historical review of the literature on scaphoid-centrale fusion in primates and the first formal investigation into the timing and frequency of this character among primates, with a focus on extant hominoids. Results indicate that there is a significant difference in the timing and frequency of scaphoid-centrale fusion in African apes and humans compared to Asian apes, suggesting that prenatal or early postnatal fusion among hominines is a synapomorphy. Scaphoid-centrale fusion does not occur randomly within primates. Instead, only Homininae and some members of Lemuroidea show consistent and ontogenetically early fusion of these carpals. The consistent occurrence of this trait within only two primate clades and a clear heterochronic trend in timing and frequency of scaphoid-centrale fusion among hominines suggest that this character is primarily phylogenetically controlled. We could not falsify the hypothesis that scaphoid-centrale fusion in African apes is indeed related to midcarpal stability in knuckle-walking, but neither were we able to find direct biomechanical or kinematic evidence to support this hypothesis. A more definitive answer to the question of the functional significance of scaphoid-centrale fusion will have to await more detailed analyses of great ape wrist kinematics.     

Handedness in great apes: A review of findings

We present data on hand preference in great apes and discuss them in the context of theoretical models of hand preference in nonhuman primates presented by MacNeilageet al. (1987) and by Fagot and Vauclair (1991). We also discuss several methodological and statistical issues as they pertain to the assessment of hand preference in great apes and other primate species. Finally, we present a comparative framework for the study of hand preference, emphasizing the importance of studies with great apes in developing evolutionary models of hemispheric specialization.     

Cranial asymmetry in Ceboid primates: The emissary foramina

Until the last decade or so, relatively little was known of cranial asymmetries in nonhuman primates. Data are slowly, but surely, accumulating for such features as transverse sinus flow, sylvian point angle differences, external brain morphology, etc. Cranial asymmetries are being analyzed and related to such diverse problems as “handedness” and phylogenetic systematics. It has been known for over 200 years that cranial asymmetry exists in some of the cerebral blood flow patterns in man, particularly the internal jugular pathway. Although earlier anatomists assumed this was only characteristic of “higher primates” (meaning man and the great apes), little quantitative data have been available to either support or deny this belief. There is a particular dearth of information for New World primates. The aim of this study is to contribute to the growing literature on cerebral asymmetries by partially filling in this gap in our knowledge of New World primate biology.     

Lunula corneae in man and primates

Imai (1931) discovered a milk-white crescent on the temporal side of the cornea in Macaca cyclopis. Afterwards he confirmed that such a crescent appears in many kinds of primates, humans and newborn babies in Japan. It was named “Lunula corneae” by Professor S. Adachi. Both workers investigated the nature of the Lunula and considered the meaning of its appearance. Further study on the same problem was carried out by the present authors, when non-transparent tissues as the pactinate ligament and sclera over the ligament. When these tissues situate under the cornea due to the spread of it, they appear as a milk-white crescent. Moreover, the present authors made a statistical investigation on the remains of the Lunula corneae, observed the crescents which were accompanied by the pigmentation in the bulbar conjunctiva and investigated from a hereditary point of view the remains of the Lunula in the Japanese.They established that the Lunula corneae on the temporal side is a sign of the enlargement of the cornea to that side, resulting in a larger visual field on the same side. This is advantageous to primates who live in the open; they exhibit the Lunula throughout life. As concerns humans in Japan, the Lunula always appears in newborn babies, but gradually disappears with age and decreases to 15·7% at 23 years of age. Accordingly, the authors consider the Lunula in man is a kind of rudiment. The Lunula in man is accompanied by the pigmentation in the bulbar conjunctiva in a very high percentage of cases. The authors envisage such a pigmentation in man as a kind of pithecoid mark. Therefore, anthropological investigations on the Lunula corneae and the pigmentation around it would be an interesting subject for study. The authors also gained an insight of the hereditary nature of the Lunula remains. In their opinion such a character is transmittable in man.     

A cross-species analysis of carnivore,primate, and hominid behaviour

The traditional assumption that the origin of human behavior is found within the higher primates rather than the social carnivores is based on failure to adequately define primate and carnivore behavior. Phyletic classification takes no account of convergence and divergence; the behavior of a species is not necessarily characteristic of its order. Of 8 behavior variables that distinguish the order primates from the order carnivora, preagricultural man resembles the carnivores on 7 items: food sharing, food storing, cannibalism, surplus killing, interspecies intolerance, feeding of young, and division of labor; resembling the order primates only in group defense. The original form of much human behavior is found within the carnivores.