bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular evolutionary processes and conflicting gene trees: The hominoid case
Authors: Ruvolo Maryellen 
Published: February 2006

AbstractMolecular evolutionary processes modify DNA over time, creating both newly derived substitutions shared by related descendant lineages (phylogenetic signal) and “false” similarities which confound phylogenetic reconstruction (homoplasy). However, some types of DNA regions, for example those containing tandem duplicate repeats, are preferentially subject to homoplasy‐inducing processes such as sporadically occurring concerted evolution and DNA insertion/deletion. This added level of homoplasic “noise” can make DNA regions with repeats less reliable in phylogenetic reconstruction than those without repeats. Most molecular datasets which distinguish among African hominoids support a human‐chimpanzee clade; the most notable exception is from the involucrin gene. However, phylogenetic resolution supporting a chimpanzee‐gorilla clade is based entirely on involucrin DNA repeat regions. This is problematic because (1) involucrin repeats are difficult to align, and published alignments are contradictory; (2) involucrin repeats are subject to DNA insertion/deletion; (3) gorillas are polymorphic in that some do not have repeats reported to be synapomorphies linking chimpanzees and gorillas. Gene tree/species tree conflicts can occur due to the sorting of ancestrally polymorphic alleles during speciation. Because hominoid females transfer between groups, mitochondrial and nuclear gene flow occur to the same extent, and the probability of conflict between mitochondrial and nuclear gene trees is theoretically low. When hominoid intraspecific mitochondrial variability is taken into account [based on cytochrome oxidase subunit II (COII) gene sequences], humans and chimpanzees are most closely related, showing the same relative degree of separation from gorillas as when single individuals representing species are analyzed. Conflicting molecular phylogenies can be explained in terms of molecular evolutionary processes and sorting of ancient polymorphisms. This perspective can enhance our understanding of hominoid molecular phylogenies. © 1994 Wiley‐Liss, Inc.
A critique of homology as a morphological concept
Authors: Cartmill Matt 
Published: February 2006

AbstractTwo sequences of nucleotides are homologous if they are descended through a chain of replication from a common precursor molecule. Since organs are not copies or transcriptions of organs, the concept of morphological homology has no such simple and unambiguous definition. The theoretical vagueness of morphological homology is reflected in its many and inconsistent criteria of identification. Structures may be conventionally deemed homologous even though they are radically dissimilar in form, relationships, or function, or develop via dissimilar ontogenetic processes, or originate from nonhomologous embryological precursors. Hypotheses of homology are conventionally rejected when they are contradicted by known patterns of phylogenetic relationships, even if the structures in question are minutely similar in their form, function, and development. The dependence of interspecific homology on phylogeny is often expressed by saying that two structures are homologous if they are inherited from corresponding structures in a common ancestor. However, this is a circular definition (what counts as a “corresponding” structure is itself a question of homology), and it falsely assumes that structures can be inherited. At bottom, homology is an essentialist concept; two things are homologous only if they are in some essential sense the “same” thing and properly called by the same word. The concept can be made intelligible in an evolutionary context only by giving it a cladistic interpretation that makes homology judgments dependent on the outcome of a phylogenetic analysis. It follows that such judgments cannot play a role in evaluating conflicting phylogenetic hypotheses. © 1994 Wiley‐Liss, Inc.
Reanalysis of the Lukeino molar (KNM‐LU 335)
Authors: Ungar Peter S. , Walker Alan , Coffing Katherine 
Published: February 2006

AbstractThis paper details a reanalysis of KNM‐LU 335, a hominoid mandibular first molar dated to about 6 Ma from the Lukeino Formation, Kenya. Researchers have argued that this molar closely resembles those of modern chimpanzees and may approximate the ancestral morphotype of humans and chimpanzees. The investigation presented here describes a morphometric study of the Lukeino molar and M1S of Homo sapiens, Pan troglodytes, and early australopithecines. Results indicate that KNM‐LU 335 differs from both human and chimpanzee M1S in relative distances (measured in three dimensions) between crown fissure termini. Further, the Lukeino molar shares with early australopithecines a pronounced flaring of the buccal surface of the crown not seen for either modern sample. Results of this study do not exclude KNM‐LU 335 as a potential ancestral morphotype for Pan and Homo but provide no evidence that this morphotype resembled modern chimpanzees. © 1994 Wiley‐Liss, Inc.
Hand dominance and bilateral asymmetry in the structure of the second metacarpal
Authors: Roy Tracey Ann , Ruff Christopher B. , Plato Chris C. 
Published: February 2006

AbstractBilateral asymmetry in the structure of the second metacarpal was examined in relation to functional hand dominance in a large, clinically nonselected, healthy population sample from the Baltimore Longitudinal Study of Aging. Bilateral bone measurements were made from anteroposterior hand radiographs of a total of 992 individuals, 609 males and 383 females, with an age range of 19–94 years. Hand dominance was determined on the basis of personal impression. Total width and medullary width at the midshaft of the second metacarpal were measured to 0.05 mm using a Helios caliper. These two measurements were used to derive cortical thickness, cortical bone area, periosteal (total) area, medullary area, percent cortical area, and the second moment of area in the mediolateral plane. In both right and left‐handed individuals, statistically significant side differences were found in the calculated bone areas and the second moment of area, with the dominant hand being larger. Cortical thickness did not show significant side‐related differences for either handedness. These results show that functional handedness leads to periosteal and endosteal expansion of the second metacarpal cortex on the dominant side, increasing bone strength without increasing cortical thickness. This is the first time this pattern of asymmetry has been reported in left‐handers as well as right‐handers. Our results argue for the primacy of environmental (mechanical) effects in determining bilateral asymmetry of limb bone structural properties. © 1994 Wiley‐Liss, Inc.
Neonatal size and infant mortality at high altitude in the western Himalaya
Authors: Wiley Andrea S. 
Published: February 2006

AbstractA prospective study was undertaken in Ladakh, India, a high‐altitude region of the Himalaya, to investigate the effects of small average birth size on neonatal mortality. While such studies exist from high‐altitude regions of the New World and shed light on the adaptive status of high‐altitude‐dwelling populations there, this is the first to examine this relationship in the Himalaya. In a sample of 168 newborns, birthweight and other anthropometric measurements were reduced relative to Andean and Tibetan newborns. Logistic regression and hazard analysis showed that neonatal biological characteristics such as weight, fatness, and circumferences were important predictors of survival probabilities of infants, especially in the neonatal period. Low Rohrer's Ponderal Index (PI) was particularly strongly related to poor survival outcome. Males and females showed no significant differences in mortality risk. Data derived from reproductive histories revealed that neonatal mortality accounted for 70–80% of total infant mortality in Ladakh. Compared to other high‐altitude studies, small newborn size in Ladakh was associated with much higher mortality risks; mortality risk rose dramatically with birthweights below the mean (2,764 grams), which characterized 50% of all newborns. It is argued that newborns in Ladakh are subject to strong directional selective forces that favor higher birthweights that incur lower risks of neonatal mortality, while Andean infants are subject to relatively mild selection pressure at both ends of the birthweight distribution. Given the overall small size at birth of Ladakhi newborns and the poor survival outcomes of newborns below the mean, it is suggested that this population is less well adapted in a biological sense to the stresses inherent in this high‐altitude environment than are Andean populations, perhaps due to the relatively recent colonization of the area and the substantial genetic admixture that has occurred in the past. © 1994 Wiley‐Liss, Inc.
Body dimensions and thyroid hormone levels in premenopausal and postmenopausal women from Austria
Authors: Kirchengast Sylvia 
Published: February 2006

AbstractCorrelations between thyroid hormone levels and body dimensions were investigated in a group of 124 premenopausal (ages 16–40 years) and 142 postmenopausal (ages 38–61 years) women from Vienna, Austria. Twenty‐nine absolute body dimensions and thirteen anthropometric indices were correlated with the serum levels of thyroxine, triiodothyronine, thyroid‐stimulating hormone, and thyroid‐hormone‐binding globulin as well as three hormone ratios (T3/T4, T4/TSH, T3/TSH). All hormones exhibited statistically significant correlations with 24 anthropometric variables and 11 indices. The correlations between thyroxine and triiodothyronine levels and the body measurements were predominantly positive in both proband groups. Higher thyroid hormone levels were associated positively with body dimensions, especially with the amount of subcutaneous fat tissue, in adult females independently of their menstrual status. The direction of the correlations between thyroid‐stimulating hormone and body measures as well as anthropometric indices differed between the premenopausal and the postmenopausal women. While in premenopausal women mainly positive correlations between anthropometric characters and the level of thyroid stimulating hormone occur, in postmenopausal women most of these correlations are negative. This is probably due to the decrease of thyroid‐stimulating hormone levels with increasing age, as well as with changes in body shape during the climacteric and after the menopause. © 1994 Wiley‐Liss, Inc.
Intra‐ and interobserver concordance in scoring Harris lines: A test on bone sections and radiographs
Authors: MacChiarelli Roberto , Bondioli Luca , Censi Laura , Hernaez Margarita Kristoff , Salvadei Loretana , Sperduti Alessandra 
Published: February 2006

AbstractLittle attention has been devoted to assessing the reproducibility of (paleo)pathological observations. Harris lines (HL) are among the markers most used to determine chronology of stresses suffered during growth. Nevertheless, their scoring entails remarkable methodological difficulty. Bone sections (S) and radiographs (R) of 29 adult tibiae of archeological provenance (medieval) were scored for HL by five observers. At regular intervals of time, each observer gave two independent counts on both series. Results show a) a substantial interobserver disagreement of HL estimates for both sectional and radiographic records, and b) a high level of intraobserver error. © 1994 Wiley‐Liss, Inc.
Limb skeleton and locomotor adaptations of apidium phiomense, an Oligocene anthropoid from Egypt
Authors: Fleagle John G. , Simons Elwyn L. 
Published: February 2006

AbstractApidium phiomense is the most common primate from the early Oligocene deposits of Fayum, Egypt. It is known from hundreds of dental remains and dozens of skeletal remains, including numerous representatives of the long bones of the forelimb and hindlimb. Apidium phiomense was a small (1,600 g) arboreal quadruped. The forelimb bones of this species show features characteristic of arboreal quadrupeds and lack characteristic features found in the forelimb bones of vertial clingers, terrestrial quadrupeds, or suspensory species. The pelvis and hindlimb bones show numerous adaptations for leaping from a quadrupedal position. In general, Apidium lacks characteristic features of either cercopithecoid monkeys or hominoid apes. Overall, the skeleton shows greatest similarities to the same elements of small platyrrhines such as Saimiri and is also very similar to the hypothetical morphotype for the ancestral platyrrhine. The skeleton of Apidium phiomense is the most primitive anthropoid postcranial skeleton known. © 1995 Wiley‐Liss, Inc.
Non‐circular geometry and radiogrammetry of the second metacarpal
Authors: Lazenby Richard 
Published: February 2006

AbstractTraditional radiogrammetry of the second metacarpal mid‐shaft reconstructs cortical cross‐sectional geometry from mediolateral (ML) linear dimensions based on a circular model. However, comparison of antero‐posterior (AP) versus mediolateral radiographic dimensions in a sample of paired metacarpals shows that AP total and medullary widths typically exceed ML widths by 5% to 10%. As well, in 13% of males and 25% of females, the two metacarpals are dissimilarly shaped, i.e., the AP/ML ratio is >1.0 for one side and <1.0 for the other. This situation exaggerates the differences in geometric properties between sides and constitutes a potentially significant source of bias for analyses of bilateral asymmetry. These results suggest that the circular model is inappropriate for estimation of cross‐sectional geometry at this anatomical location. © 1995 Wiley‐Liss, Inc.
Genetic structure of the population of Cabo Verde (West Africa): Evidence of substantial european admixture
Authors: Parra E. J. , Ribeiro J. C. Teixeira , Caeiro J. L. B. , Riveiro A. 
Published: February 2006

AbstractThe population of Cabo Verde was founded in the fifteenth century (1462), on the basis of slaves brought from the West African coast and a few Europeans, mainly from Portugal. The polymorphism of six red cell enzymes (ADA, AK1, ALAD, ESD, GLO1, and PGD) and ten plasma proteins (AHSG, BF, F13A, F13B, GC, HP, ORM, PLG, TBG, and TF) was studied in a sample of 268 individuals from Cabo Verde (West Africa). There is no statistical evidence of genetic heterogeneity between the two groups of islands which constitute the archipelago, Barlavento and Sotavento. The gene frequency distribution observed in Cabo Verde differs, in many markers, from that of West African populations, suggesting an important European influence. The proportion of Caucasian genes in the population of Cabo Verde has been calculated to be M = 0.3634 ± 0.0510, and the considerable dispersion of the locus‐specific admixture estimates seems to indicate random drift has also played a role in the evolution of the allele frequencies in the archipelago. Partition of the variance of the mean estimate in evolutionary and sampling variance shows the evolutionary variance is more than ten times higher than the sampling variance. When dendrograms are constructed on the basis of different genetic distances, the population of Cabo Verde clusters with Afro‐Americans, forming a different group from the populations of the African continent. This is interpreted as a consequence of the importance of Caucasian admixture both in Afro‐Americans and in the population of Cabo Verde. © 1995 Wiley‐Liss, Inc.
Growth differences between children of highland and coastal Ecuador
Authors: Leonard William R. , DeWalt Kathleen M. , Stansbury James P. , McCaston M. Katherine 
Published: February 2006

AbstractThis study examines patterns of growth in height and weight among children (<60 months) of highland and coastal agricultural communities of Ecuador. Highland children are significantly shorter, but not significantly lighter than their coastal peers. Linear growth rates (cm/6 months) are comparable between the two samples. Growth rates for body weight (kg/6 m) are similar in highland and coastal boys, whereas highland girls display larger weight gains than their coastal counterparts. In both regions, linear growth is compromised to a much greater extent than growth in body weight, and growth faltering for both height and weight is most pronounced between birth and 24 months of age.The similarity in growth rates between the highland and coastal samples suggests that high altitude hypoxia plays a relatively small role in shaping growth during the first five years after birth. Rather, it appears that most of the disparity in height between the two samples can be attributed to differences established by 6 months of age. The pattern of growth retardation seen in both regions during the first 24 postnatal months is similar to that observed among impoverished populations throughout the world and is likely associated with the influence of nutritional and disease stressors. After 2 years of age, little or no “catch up” growth is seen in height, whereas improvements in weight gain are more pronounced, especially among highland girls. Ongoing research is investigating the nutritional and socio‐economic correlates of growth within each region. © Wiley‐Liss, Inc.
Natural selection and developmental sexual variation in the human pelvis
Authors: LaVelle Marquisa 
Published: February 2006

AbstractThis research examines ontological patterns of change in variation of the human pelvis as a means of identifying regions of differential growth, growth canalization and evidence of selection. Data were derived from pelvic radiogrammetry of 180 8‐year‐olds and 89 subjects at age 18 who were part of the Fels Longitudinal Growth Study. Coefficients of variation (CVs) and total growth increments were compared between sexes and between ages 8 and 18 for 14 pelvic measures. Sex‐specific comparisons of mean size were tested per age using Student's t, whereas coefficients of variation were calculated and compared using the methods suggested by Sokal and Braumann ([1980] Syst. Zool. 29:50–66). The Mann‐Whitney U‐test was used to test median growth increments between ages 8 and 18.Results of these comparisons show significant sex differences in breadth of the ischium and acetabular regions among 8‐year‐olds. Most of the sexual dimorphism in the pelvis at age 18, however, develops during the adolescent growth period, during which both male and female pelves undergo growth remodeling of the pelvic cavity. Over the same time period, males show significantly greater incremental growth in the acetabulum, and females show differentially greater growth in the pelvic cavity. At age 18, the pelvis demonstrates a posterior‐to‐anterior gradient of increasing dimorphism within the inlet and midplane of the pelvic birth canal.As a means of interpreting the effects of natural selection on the pelvis, it is argued that appropriate comparisons are within‐sample comparisons of CVs over time, rather than comparisons between sexes of adult coefficients as has been argued by others (Meindl et al. [1985] Am. J. Phys. Anthropol. 68:79–85). Analyses of change in coefficients of variation over time show evidence of concordantly reduced within‐sample variation in 7 pelvic dimensions indicating canalization of growth. These results are attributed to the effects of stabilizing selection operating on both males and females and include transverse diameters of the sacrum, inlet, anterior inferior iliac spines, and breadths of the ilium and ischium.Six pelvic dimensions show evidence of increased total sample CVs and discordant change in within‐sex comparisons of CVs as well as differential growth between sexes over time. This pattern is indicative of the effects of disruptive selection on the pelvis for interacetabular diameter, breadths of the anterior superior and posterior inferior iliac spines, pubic length, and ilium height. © Wiley‐Liss, Inc.
Euclidean distance matrix analysis: Confidence intervals for form and growth differences
Authors: Lele Subhash , Richtsmeier Joan T. 
Published: February 2006

AbstractAnalysis of biological forms using landmark data has received substantial attention recently. Much of the statistical work in this area has concentrated on the estimation of average form, average form difference, and average growth difference. From the statistical, as well as the scientific point of view, it is important that any estimate of a scientifically relevant quantity be accompanied by a statement regarding its accuracy. Such a statement is contained in a confidence interval. The purpose of this paper is to provide a method to obtain confidence intervals for form difference and growth difference estimators. The estimators are based on Euclidean distance matrix analysis. The confidence intervals are calculated using the model independent bootstrap method. We illustrate the method by using three examples: morphological differences between samples of craniofacial patients and normal controls using two dimensional data from head X‐rays, sexual dimorphism of craniofacial morphology inCebus apella, and sexual dimorphism of facial growth inCebus apellausing three‐dimensional data. © Wiley‐Liss, Inc.
Paleopediatrics: Or when did human infants really become human?
Authors: Conroy Glenn C. , Kuykendall Kevin 
Published: February 2006

AbstractModern human children take about twice as long as their closest biological relative, the chimpanzee, to mature. One standard explanation for the evolution of “delayed maturation” at an early stage of human evolution is that it provided the time necessary for immature individuals to learn complex skills, most notably those relating to tool‐making abilities. However, after comparing dental maturational profiles of early hominids from South Africa (who apparently did make and use stone tools) (Susman [1994] Science 265:1570–1573) to those of extant humans and chimpanzees, we find no evidence to document an association between “delayed maturation” and tool‐making abilities in the early stages of human evolution. This also suggests that the assumed association between prolonged childhood dependency and other behaviors often associated with the advent of tool‐making such as cooperative hunting, food sharing, home bases, sexual division of labor, etc., is also suspect. Instead, we must look for other, or additional, selective pressures for the evolution of “delayed maturation,” which may postdate the australopithecine radiation. © 1995 Wiley‐Liss, Inc.