bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of masticatory morphology between Rhinopithecus bieti and R. roxellana
Authors: Pan Ruliang , Yanzhang Peng , Zhizhang Ye , Hong Wang , Fahong Yu
Published: June 2005

The masticatory apparatus for two endemic species of golden monkey in China, Rhinopithecus bieti and Rhinopithecus roxellana, were compared with those of macaques, Macaca and leaf monkeys, Presbytis. Multivariate analyses demonstrated that the two golden monkey species are distinct. Interspecies allometric analyses revealed that golden monkeys differ in their masticatory apparatus from both macaques and leaf monkeys. The prominent symphysial fusion, corpus, and sagittal condylar dimension of R. roxellana may produce efficient biting force on the incisal and posterior canine teeth, with the heavy reaction force born on the temporomandibular joint. However, the well‐developed bizygamatic width and mandibular height in R. bieti suggest that posterior canine function is similarly prominent in R. roxellana, while incisal function is not. © 1995 Wiley‐Liss, Inc.
Diurnal and annual variation of adrenocortical activity in the squirrel monkey
Authors: Coe Christopher L. , Levine Seymour
Published: June 2005

Diurnal changes in basal cortisol levels and stress reactivity were assessed in male and female squirrel monkeys. Blood samples were collected at four‐hour intervals throughout the day and night in the mating and nonmating seasons. Basal cortisol levels in females were similar in both seasons, but males tended to have higher cortisol levels during the mating season, especially at night. For both sexes, cortisol secretion was highest between 0400 and 0800 preceding the onset of the diurnal activity period. Assessment of cortisol responses following brief handling and anesthesia indicated that stress responses were relatively stable across the year, but cortisol increments were slightly higher in the nonmating season. Cortisol levels post‐stress were generally related to prior baseline values. Thus, a knowledge of biorhythmic changes in basal hormone levels was important for predicting hormone levels after acute stressors. Males also underwent marked seasonal variation in their basal testosterone levels, which markedly altered the nature of their testosterone responses 30‐minutes poststress. © 1995 Wiley‐Liss, Inc.
Characteristics of chimpanzee (Pan troglodytes) ejaculates collected by rectal probe electrostimulation and by artificial vagina
Authors: Young L. G. , Smithwick E. B. , Gould K. G.
Published: June 2005

This study compares characteristics of ejaculates collected from 16 adult male chimpanzees using rectal probe electrostimulation (RPE) and from 10 adult male chimpanzees trained to use an artificial vagina (AV). Ejaculate weight, semen volume, and sperm number were significantly lower (P < 0.01) and percentage liquefaction was significantly higher (P < 0.01) in ejaculates collected by RPE. Percentages of motile sperm and of live sperm in semen did not differ significantly between the two collection methods. Total amounts of protein and of α‐glucosidase activity were significantly lower (P < 0.01) in seminal fluid from RPE samples. For ejaculates collected by RPE, semen volume correlated positively with protein (r = 0.8640, P < 0.001), fructose (r = 0.6976, P < 0.001), and citrate (r = 0.6976, P < 0.001); sperm number correlated positively with α‐glucosidase activity (r = 0.6547, P < 0.001); and protein correlated positively with fructose (r = 0.5906, P < 0.002), citrate (r = 0.5926, P < 0.002) and α‐glucosidase activity (r = 0.6006, P < 0.001). For ejaculates collected by AV, semen volume correlated positively with percentage liquefaction (r = 0.6058, P < 0.001), protein (r = 0.8055, P < 0.001), fructose (r = 0.6606, P < 0.001), and citrate (r = 0.8272, P < 0.001); sperm number correlated positively with percentage of motile sperm (r = 0.4196, P 0.004); percentage of motile sperm correlated positively with percentage of live sperm (r = 0.4388, P < 0.002); and, protein correlated positively with fructose (r = 0.6947, P < 0.002) and with citrate (r = 0.5926, P < 0.002). These data show that there is a significant difference in semen parameters and in biochemical parameters of ejaculates obtained by RPE and by AV. © 1995 Wiley‐Liss, Inc.
Quantifying synchrony among reproductive or other states
Authors: Rhine Ramon J.
Published: June 2005

Synchrony among reproductive or other states is a widespread phenomenon of significance in evolutionary theory. A model is presented for use in the measurement of the degree of synchrony in any set of behavioral or biological states, such as menstrual cycling, pregnancy, or lactation. At a given time, maximum group synchrony occurs when all members of a group are in a single state, minimum synchrony occurs when equal numbers are in all states, and intermediate values of synchrony occur for other proportional representations of the states. The model yields group synchrony scores ranging from 0 to 100 by standardizing the average of the absolute deviations among frequencies of occurrence in pairs of states. In addition, individual synchrony is characterized by the proportion of others who share an individual's state at a specified set of times. Properties of the model are discussed, simplified calculation procedures are presented, and the method's usefulness for comparative purposes is illustrated. © 1995 Wiley‐Liss, Inc.
Application of fecal steroid techniques to the reproductive endocrinology of female verreaux's Sifaka (Propithecus verreauxi)
Authors: Brockman Diane K. , Whitten Patricia L. , Russell Elizabeth , Richard Alison F. , Izard M. Kay
Published: June 2005

Solid phase extraction, high performance liquid chromatography, and radioimmunoassay were used to test the validity of fecal steroid analysis for assessing ovarian function in sifaka (Propithecus verreauxi). Daily fecal samples were collected over a 4 month period from two cycling female sifaka, and single samples were collected from females during normal gestation and males while housed at the Duke University Primate Center. Tests of radioimmunoassay validity indicated that solid phase extraction and microradioimmunoassay techniques were reliable and accurate methods for quantifying ovarian steroids in sifaka feces. The progesterone (P4) antibody specifically quantitated only P4, while several estrogen metabolites made small contributions to immunoreactive measures of estradiol (E2). A 1:10 dilution reduced these contributions to 3–15% of the estimated E2 concentration. Although the spectral data suggested that E2 was not the major metabolite present, it accounted for the majority of the immunoreactivity at normal assay dilutions. Fecal profiles of immunoreactive E2 and P4 in the conceptive female resembled serum profiles of other strepsirhines. E2 and P4 were elevated at the end of the conceptive cycle and were more markedly increased in late pregnancy in the two pregnant females. Mating behavior and indices of sexual interest were observed in conjunction with E2 peaks, although not all peaks were accompanied by observations of sexual behavior. © 1995 Wiley‐Liss, Inc.
Assessment of female reproductive status in captive‐housed Hanuman langurs (Presbytis entellus) by measurement of urinary and fecal steroid excretion patterns
Authors: Heistermann M. , Finke M. , Hodges J. K.
Published: June 2005

The study reports on the use of urinary and fecal hormone measurements for monitoring female reproductive status in captive‐housed Hanuman langurs (Presbytis entellus). Matched urine and fecal samples collected throughout 7 complete menstrual cycles of two females, and during part of one pregnancy in a third female were analyzed. Estrone conjugates (E1C) and immunoreactive pregnanediol glucuronide (PdG) in urine and immunoreactive estradiol (E2), progesterone (P4), pregnanediol (Pd) and 20α‐hydroxyprogesterone (20αOHP) in feces were measured by enzymeimmunoassay. E1C and PdG in urine were excreted in a cyclic pattern with E1C levels increasing 3‐ to 4‐fold during the follicular phase to reach preovulatory peak values 2 days before a defined rise in PdG concentrations. Cycle lengths ranged between 20 and 34 days comprising a variable follicular phase of 7–21 days and a more consistent luteal phase of 12–14 days. High pressure liquid chromatography (HPLC) analysis of fecal extracts confirmed the presence of all fecal hormones measured, but indicated large amounts of additional immunoreactivity in the three progestin assays. The patterns of excretion of fecal E2 and all three fecal progestins corresponded well with those of steroid metabolites in urine in showing a clear and well defined follicular phase E2 rise followed by a luteal phase progestin increase. Measurement of 20αOHP immunoreactivity revealed the most stable baseline and the highest follicular/luteal phase differential. Levels of all hormones were clearly elevated during pregnancy although urinary E1C and PdG showed a more pronounced increase compared to fecal metabolites. The results indicate that urinary and fecal hormone analysis can be applied to noninvasive monitoring of reproductive status in the Hanuman langur. © 1995 Wiley‐Liss, Inc.
Insect secretions determine habitat use patterns by a female lesser mouse lemur (Microcebus murinus)
Authors: Corbin Greg D. , Schmid Jutta
Published: June 2005

The lesser mouse lemur (Microcebus murinus) is one of six sympatric nocturnal primates found in the Kirindy forest, west‐Madagascar. Each of these species is reported to consume a secretion produced during the austral winter by the Homopteran insect Flatidia coccinea. In July and August 1993 a study was conducted to determine the importance of this food resource in the ecology of female M. murinus. At this study site, animals were distributed only along the forest edge where insect secretions are significantly more abundant than in the forest interior. Abundances of arboreal and nocturnal flying insects do not differ between the forest edge and interior. Experimental resource removal from a 25 × 25 m plot in one female's home range caused a significant shift in the animals' pattern of habitat use while no change occurred in a control plot. Thus, at this study site and time of year, the ranging behavior of a female M. murinus was strongly influenced by the presence of Homopteran secretions. © 1995 Wiley‐Liss, Inc.
Uranium series dating in paleoanthropology
Authors: Schwarcz Henry P.
Published: June 2005

Many hominid and archaeological sites contain materials that were formed or deposited synchronously with the site and can be dated by uranium‐series methods, principally 230Th/234U dating. The range of the method is approximately 350,000 years. U‐series dating yields most accurate results when applied to chemically precipitated calcium carbonate, which occurs in stalagmitic layers, travertines, and lacustrine limestones. Materials such as bone and shell are less reliable. Using mass spectrometry (MS), a precision of ±1% is attainable, whereas conventional alpha counting optimally gives a precision of ±5%. Mass spectrometric dating requires smaller samples, potentially allowing determination of ante quem dates for calcite coatings on hominid fossils and associated faunal skeletons.
New views on primate origins
Authors: Cartmill Matt
Published: June 2005

Most primates live in trees, and many of them have strikingly human‐like hands and faces. Scientists who study primate evolution agree that these two facts must be connected in some way. The details, however, are a matter of debate. Early theories explained the human‐like peculiarities of primates simply as arboreal adaptations. More recent accounts have traced the origins of these peculiarities to more specific ways of arboreal life, involving leaping locomotion, shrub‐layer foraging, visually guided predation on insects, or fruit‐eating.
Functional morphology of the human chin
Authors: Daegling David J.
Published: June 2005

The protruding chin is an attribute that defines modern Homo sapiens to the exclusion of all other primates, including fossil hominids. The functional significance of the chin has been contemplated for most of the 20th century, but as yet no compelling functional argument for its evolution has withstood careful scrutiny. Consequently, the human chin is often cited as an example of a nonadaptive trait. Past attempts to explain the chin in a functional or mechanical context have failed, largely as a result of an incomplete understanding of in vivo masticatory biomechanics. When the morphology of the chin is considered in light of experimental data on mastication, its evolution can be interpreted as a consequence of recent changes in mandibular proportions that have altered the relative importance of different masticatory stresses. Hypotheses proposing that chin morphology is the result of sexual selection or spatial constraints may be untestable. As with arguments that posit no functional role for the chin, the credibility of these hypotheses has depended, to a large degree, on the refutation of previous biomechanical explanations.
Soils, time, and primate paleoenvironments
Authors: Bown Thomas M. , Kraus Mary J.
Published: June 2005

Soils are the skin of the earth. From both poles to the equator, wherever rocks or sediment are exposed at the surface, soils are forming through the physical and chemical action of climate and living organisms. The physical attributes (color, texture, thickness) and chemical makeup of soils vary considerably, depending on the composition of the parent material and other variables: temperature, rainfall and soil moisture, vegetation, soil fauna, and the length of time that soil–forming processes have been at work. United States soil scientists1 have classified modern soils into ten major groups and numerous subgroups, each reflecting the composition and architecture of the soils and, to some extent, the processes that led to their formation. The physical and chemical processes of soil formation have been active throughout geologic time; the organic processes have been active at least since the Ordovician.2 Consequently, nearly all sedimentary rocks that were deposited in nonmarine settings and exposed to the elements contain a record of ancient, buried soils or paleosols. A sequence of these rocks, such as most ancient fluvial (stream) deposits, provides a record of soil paleoenvironments through time.

Paleosols are also repositories of the fossils of organisms (body fossils) and the traces of those organisms burrowing, food–seeking, and dwelling activities (ichnofossils). Indeed, most fossil primates are found in paleosols. Careful study of ancient soils gives new, valuable insights into the correct temporal reconstruction of the primate fossil record and the nature of primate paleoenvironments.
Early paleolithic of China and eastern Asia
Authors: Schick Kathy D. , Zhuan Dong
Published: June 2005

In attempting to understand the course of human evolution and the nature of hominid adaptation over the past few million years, it is necessary to consider prevailing evidence from all parts of the world. Eastern Asia provides a range of important questions and challenges with regard to this evolutionary puzzle. Although evidence for earlier ape evolution is present in China (for example, at Lufeng in Yunnan Province), the earliest evidence for hominid presence appears to be in the Early Pleistocene, apparently the result of a migration of hominids to and subsequent adaptation within Eastern Asia. The archeological record provides a closer look at some technological aspects of this adaptation during the Early and Middle Pleistocene, showing both distinctive contrasts and intriguing continuities relative to the rest of the Old World.
The attraction of paleomagnetism
Authors: Kappelman John
Published: June 2005

The majority of fossil primates and human archeological sites are recovered from sedimentary rocks, but obtaining radioisotopic dates directly from rocks of this type is generally difficult. Paleomagnetism offers an alternative dating approach. Specific applications of paleomagnetism in the field of anthropology range from dating late Eocene fossil anthropoids to determining human archeological site use and occupation. This single dating technique is not restricted to a specific time range, but can be used across the entire span of primate evolution. When linked with other dating techniques, such as radioisotopic or astrochronologic methods, paleomagnetism offers a high level of temporal resolution in unraveling questions of the past.
A tooth, a toe, and a vertebra: The genetic dimensions of complex morphological traits
Authors: Weiss Kenneth M.
Published: June 2005

Most readers probably share with me the profoundly affecting experience of wandering through a natural history museum and being surrounded by the skeletal remains of our vertebrate predecessors. Who does not stand in awe before these scaffolds of the great dinosaurs or ponder the groping stages through which our primate ancestors explored the skeletal and dental opportunities of forest life (Fig. 1)? How did this proliferation of limbs, teeth, and vertebrae, not to mention the complexity we can infer about the overlying anatomy and physiology, arise from the simple early forms of animal life? How did DNA evolve to contain the program for such complexity?
Paleobiology of the first Americans
Authors: Steele D. Gentry , Powell Joseph F.
Published: June 2005

The majority of scholars studying the human colonization of the New World agree that the first Americans, traditionally identifed as Paleoindians, entered near the end of the Pleistocene via the Bering land bridge from northeast Asia. But this is where agreement ends. Questions about the number and timing of migrations, the physical appearance of the colonists, and the manner in which they lived have been examined since the turn of the century1–7 and still engender lively debate.8–16 Curiously lacking from the growing body of data on the peopling of the Americas is evidence from the physical remains of the first Americans. We summarize research on the earliest human remains from North America and discuss how these remains shed new light on these unanswered questions.
Our ancestors' ancestor: Ouranopithecus is a greek link in human ancestry
Authors: de Bonis Louis , Koufos George D.
Published: June 2005

Recent discoveries of the late Miocene hominoid Ouranopithecus shed new light on the evolution of hominids. These discoveries result from the strategy of the Allied armies during the First World War. In the midst of “the war to end all wars,” the North African soldiers of Camille Arambourg excavated the first mammalian fossils found in northern Greece, in the region of Macedonia, the country of Alexander the Great. On the tracks of these strange paleontological pioneers, a modern French and Greek team has unearthed a large hominoid primate, a missing link between fossilapes and primitive Australopithecus, which lived in southeastern Europe 9 to 10 million years ago. A reconstruction of Ouranopithecus and its surroundings gives us a rare glimpse into the world of the earliest hominids.
Measuring genetic admixture in human populations: The gila river story
Authors: Williams Robert C.
Published: June 2005

Admixture between human populations is the norm rather than the exception. Many groups practice deme exogamy, so that all marriages include one spouse from an outside group. Typically, that group is a nearby population, but in many areas, especially since the advent of post‐agricultural times, human movement has been greater and matings have occurred between ever more disparate groups. Because evolution is a response to local conditions, and occurs in the context of the overall genetic variability of local groups, admixture may be an important factor in human evolution and adaptation. To understand the potential impact of admixture on human evolution, it is important to know the effect of admixture on the geographic distribution of human variation.
Paleodemography: “Not quite dead”
Authors: Konigsberg Lyle W. , Frankenberg Susan R.
Published: June 2005

As Kim Hill1recently noted inEvolutionary Anthropology, humans are unique among the hominoids with regard to the length of their lives, as well as other elements in the individual life histories. The evolutionary details that modified a basic pongid life history into a hominid one remain obscure, but aspects of recent human demographic history are assailable. Study of the last 10,000 years or so is an important part of ongoing anthropological discourse, for demographic changes may be intimately linked to such major developments as agriculture and urbanization.2‐8Whether demographic changes are antecedents for or consequences of these major developments is a matter of great contention, but at the least we should attempt to document the nature of human demographic changes in the recent past. Although this documentation can take different forms, the principal sources are archeological information on past settlement patterns and analyses of prehistoric human skeletal material.
Variations in primate color vision: Mechanisms and utility
Authors: Jacobs Gerald H.
Published: June 2005

Among mammals, only the primates have acquired the biological machinery needed for highly acute color vision. That distinction led Gordon Walls, perhaps the foremost authority on comparative vision of this century, to suggest long ago that “the color vision of the higher primates is assuredly a law unto itself, genetically and historically speaking.”1 Primate color vision is indeed unique. One manifestation of this uniqueness is that color vision abilities vary significantly, not only between some groupings of primate species, but, remarkably, among individuals of a considerable number of species. Although the functional significance of these variations remains, in large measure, to be sorted out, the past decade has brought much progress in revealing the mechanisms that underlie variation.
Genetics and modern human origins
Authors: Relethford John H.
Published: June 2005

The past decade has brought considerable debate on the subject of modern human origins. The nature of the transition from Homo erectus to archaic Homo sapiens to modern H. sapiens has been examined primarily in terms of the relative contribution of archaic populations to later moderns, both within and among geographic regions. The recent African origin model proposes that modern humans appeared first in Africa between 100,000 and 200,000 years ago, and then spread through the rest of the Old World, replacing preexisting populations.1–6 This model has been referred to by a variety of names, including “replacement”, “Garden of Eden”, “Noah's Ark”, and “out of Africa”. The recent African origin model contrasts with the multiregional model, which proposes a species‐wide transition to modern humans throughout the Old World during the past million years or more.7–10 Indeed, some proponents of the multiregional model advocate placing Homo erectus and all subsequent species of Homo in the evolutionary species Homo sapiens.11 This contrasts with the view that there were multiple hominid species during the Middle Pleistocene. The debate continues.12,13 Although the multiregional model is often portrayed as proposing a simultaneous transition to anatomically modern humans in different geographic regions, it explicitly allows for varying degrees of continuity across time and space.10 This model, in the broad sense, does not rule out the possibility that modern human morphology appeared first in Africa and then spread through the rest of the Old World through gene flow. However, not all advocates of the multiregional model adhere to this specific subset of the general model.9

Comparison of the African and multiregional models is complicated by considering other, less extreme, hypotheses. Some versions of the recent African origin model imply a speciation event associated with the initial origin of modern humans. Another version, which suggests the possibility of some admixture between “moderns” leaving Africa and preexisting “archaics” elsewhere in the Old World,14,15 is similar to some variants of the multiregional model, which also suggest that modern morphology appeared first in Africa, but involved admixture with other Old World populations.16 The major difference between these views appears to be the extent of admixture, although the exact level is never specified. A further complication is the possibility that multiple dispersals from Africa produced a more complicated pattern of worldwide variation.17
Sexual selection and sperm competition in primates: What are male genitalia good for?
Authors: Harcourt Alexander H.
Published: June 2005

One hundred twenty‐five years ago, inThe Descent of Man and Selection in Relation to Sex,1Charles Darwin proposed the theory of sexual selection, as distinct from natural selection, to explain why, in some species, males have such magnificent ornaments and, in other species, such impressive weapons. He suggested two processes, which we now term female choice and male‐male competition: either females choose particularly ornate males or, alternatively, relatively passive females accept the winner of fights among males. By now, knowledge of species in which the females are more brightly colored or aggressive than males has led to a more general formulation of the principle of sexual selection, in which, instead of “females”, we write “the sex with the lower potential reproductive rate”, and, instead of “male”, “the sex with the higher potential reproductive rate”.2
Radiocarbon dating: The continuing revolution
Authors: Taylor R. E.
Published: June 2005

Radiocarbon (14C) dating, now in its fifth decade of general use, continues to be the most widely employed method of inferring chronometric age for late Pleistocene and Holocene age materials recovered from archeological contexts. Over the last decade, several technical advances in 14C studies have provided contexts for a number of significant applications in archeology that were previously either not possible or not practical. These include the extension of the calibrated 14C time scale into the late Pleistocene and the development of accelerator mass spectrometry (AMS). The contribution of AMS‐based 14C values to the critical evaluation of archeological data is illustrated by considering the problems of dating early plant domestication in the Near East and Mesoamerica, New World Paleoindian human skeletal materials, and European Upper Paleolithic and Mesolithic materials.
A Genetic study of hypoalphalipoproteinemia
Authors: Byard P. J. , Borecki I. B. , Glueck C. J. , Laskarzewski P. M. , Third J. L. H. C. , Rao D. C. , Motulsky A. G.
Published: June 2005

Complex segregation analysis under the unified mixed model of inheritance (major gene and multifactorial) is performed on families ascertained through 23 probands with hypoalphalipoproteinemia (depressed HDL‐cholesterol, denoted HDL‐c). Evidence for segregation of a recessive major gene for depressed HDL‐c with frequency q = 0.116, in addition to multifactorial transmission (H = 0.572), is found in these families. Reanalysis of a subset of families with severely depressed HDL‐c confirms the conclusions based on the original analysis, except that different definitions of “affection” give rise to different estimates of gene frequency. Our finding of a recessive mode of inheritance differs from previous claims for a dominant gene because previous analyses did not use a mixed model for segregation analysis of hypoalphalipoproteinemia. When the significant multifactorial background is neglected, we also find evidence for the invalid claim of a dominant gene. This demonstrates the necessity of using mixed models for determining the mode of inheritance of a given phenotype.
The information contained in multiple sibling pairs
Authors: Hodge Susan E. , Rao D. C.
Published: June 2005

In a sibship of size s, s(s − 1)/2 sib pairs can be formed, but these pairs are statistically dependent when s > 2. This study examines how much independent information is obtained when all possible pairs are used to evaluate the sharing of genes identical by descent. A logarithmic measure of information, Σpilog2pi [Shannon, 1948], is used. The basic unit of information is the binomial “bit,” or the amount of information in the toss of a fair coin. It is shown that a single independent sib pair contains 1.5 bits. The complete sibship contains a total of 2s−3 + (1/2)s−1 bits, or (2s−3 + (1/2)s−1)/1.5 pair‐equivalents of information. The information is reduced if all sib genotypes do not occur with equal probability.
Genetic analysis workshop II: Segregation and three‐locus linkage analysis
Authors: Bishop D. T. , Cannon L. A. , Hasstedt S. J. , Skolnick M. H.
Published: June 2005

Data simulated for Genetic Analysis Workshop II were analyzed using PAP. Segregation analysis showed a simple recessive mode of inheritance for data set 2 while no conclusions could be made about the mode of inheritance for data set 3. Pairwise linkage analysis suggested three linkage groups, but three‐locus analysis did not provide strong evidence for the gene order within these groups. For three of the four three‐locus comparisons performed, three‐locus analysis suggested the simulated order. In only one case did the pairwise analysis suggest the simulated order, indicating the necessity for multi‐locus analysis for gene order.
Genetic analysis workshop II: Sib pair screening tests for linkage
Authors: Elston R. C.
Published: June 2005

For each marker locus and for every pair of sibs with data available in the 1983 workshop data, the proportion of genes identical by descent was estimated. The mean proportions were compared between concordant and discordant sib pairs, and the mean proportion for concordantly affected pairs was compared with one half. Together with standard tests of association, these were found to be sensitive screening tests for linkage.
Genetic analysis workshop II: Multiple‐locus segregation analysis incorporating linkage markers
Authors: Risch N.
Published: June 2005

The workshop data were examined using a newly developed methodology (MILINK, Risch, 1984) for combined segregation, linkage, and association analysis of a complex disease trait in pedigree data. Results from problems two and three suggest that the method is powerful both for determining mode of disease inheritance and for resolution of linkage disequilibrium versus pleiotropy (with epistasis) of marker alleles.
The Cincinnati lipid research clinic family study: Analysis of commingling and family resemblance for fasting blood glucose
Authors: Laskarzewski P. M. , Rao D. C. , Glueck C. J. , Nance Walter E.
Published: June 2005

Our specific aim in this study was to investigate commingling and family resemblance for fasting blood glucose in 160 randomly selected white families from the Princeton School District Lipid Research Clinics Family Study. Adjustment of fasting blood glucose for the influence of age, sex, and the use of oral contraceptives and construction of indices were performed simultaneously using multiple regression methods. Path analysis was carried out, constructing an environmental index based on special diet usage, hematocrit, and obesity, which was also adjusted for the influences of age and sex. Commingling analysis and segregation analysis using the mixed model were also performed. Nearly 16% of the variance of fasting blood glucose was accounted for by age and sex. Obesity itself, which constituted the index, explained an additional 4% of the variance of fasting blood glucose. Significant genetic heritability for fasting blood glucose was documented by both path analysis and segregation analysis. In aggregate, we conclude that though there was a major familial vector accounting for within‐family aggregation of blood glucose, it was probably generated by a multifactorial component as compared to a major locus. Under the most parsimonious model, path analysis estimated the genetic and cultural heritabilities as h2 = .39 ± .08 and c2 = .06 ± .03., respectively.
Familial resemblance on the thurstone activity scale, systolic blood pressure, and total cholesterol among first degree relatives of subjects with and without coronary heart disease
Authors: Carmelli Dorit , Rosenman Ray , Rao D. C.
Published: June 2005

An investigation of the pattern of familial resemblance of three different risk factors assessed in families of coronary heart disease (CHD) patients and controls is presented. The fathers of these families participated in the Western Collaborative Group Study that first established the type A/B behavior pattern as an independent risk factor for CHD. A recently developed methodology, the Structured Exploratory Data Analysis (SEDA), was implemented to examine parental interaction, parent‐offspring closeness, assymmetries in transmission, and other differences in the pattern of familial similarities among family members of case and control subjects. The analysis performed revealed pronounced parent‐child similarity for total serum cholesterol values in both case and control families; spouse closeness and parent‐child resemblance for systolic blood pressure measurements only in control families; and sex asymmetries in the parent‐child closeness on pace of activity, which also differed between case and control families. The results of this investigation underscore the value of examining the joint pattern of familial resemblance of a number of risk factors as a means for differentiating between cultural and biological factors affecting familial aggregation of CHD.
A comparison of sib‐pair linkage tests for disease susceptibility loci
Authors: Blackwelder William C. , Elston Robert C. , Rao D. C.
Published: June 2005

An analytical study is conducted of the properties of statistical tests to detect linkage between a disease locus and a very polymorphic marker locus when data on sib pairs are available. In most instances the most powerful test is the test based on the mean number of marker alleles shared identical by descent by the two members of a sib pair, and the most efficient sampling strategy is almost always to sample only pairs with both sibs affected. We show it is valid to use the information from all possible sib pairs as though they came from separate families when data on sibships of size three or larger are available, though more power may be obtained if different weights are given to the different sibship sizes.
Genetic and environmental influences on the size and number of cells in the blood
Authors: Whitfield J. B. , Martin N. G. , Rao D. C.
Published: June 2005

The heritabilities of human blood cell characteristics were estimated in a study of 206 pairs of young adult twins, male and female. White cell numbers, indices related to circulating red cell mass (haemoglobin, red cell count, and haematocrit), and platelet numbers and size all appeared to be accounted for by genetic and nonshared environmental influences only. Mean cell volume (of the erythrocytes) appeared to be influenced by environmental factors shared by siblings as well as the other two sources of variation.

Correlation between red cell count and haemoglobin is modulated by both genetic and environmental factors, but the negative correlation between red cell numbers and size is due mainly to genetic factors independent of those influencing haemoglobin. A significant negative correlation also exists between platelet numbers and size.

In males, alcohol consumption increased mean cell volume, and genetic factors influencing alcohol consumption are partly responsible for the correlation between them.
Familial aggregation in chronic obstructive pulmonary disease: Use of the loglinear model to analyze intermediate environmental and genetic risk factors
Authors: Khoury Muin J. , Beaty Terri H. , Tockman Melvyn S. , Self Steven G. , Cohen Bernice H. , Rao D. C.
Published: June 2005

To examine the contribution of environmental and genetic risk factors to familial aggregation in chronic obstructive pulmonary disease (COPD), 325 first‐degree (ld) relatives and 56 spouses of 150 COPD patients were compared with 222 ld relatives and 49 spouses of 107 nonpulmonary patient controls for the prevalence of two clinical outcomes: 1) airways obstruction (AO; 1‐sec forced expiratory volume < 68% of forced vital capacity) and 2) chronic bronchitis (CB; cough and sputum for 3+ months per year for 2+ years). The loglinear model was used to study direct and indirect (ie, those mediated by other risk factors) components of familial aggregation. Three risk factors were found to be independently associated with CB and/or AO: α1‐antitrypsin deficiency (PiZ allele), personal cigarette smoking, and parental cigarette smoking. Because ld relatives of COPD patients were more likely to have a PiZ allele, be heavy smokers (1 + packs per day), and be exposed to parental smoking than ld relatives of controls, these three factors also constitute indirect components of familial aggregation. However, after controlling for the three factors, ld relatives of COPD patients were more likely to have AO and CB than ld relatives of controls (direct component). This direct component might have a genetic basis, because no such association was found when spouses instead of ld relatives were compared. Thus, both shared environmental factors (personal and passive smoking) and shared genetic factors (α1‐antitrypsin and a possible direct genetic component) contribute to familial aggregation in COPD. The loglinear model provides a useful tool for analyzing familial aggregation in diseases of multifactorial etiology.
The collaborative Lipid Research Clinics family study: Biological and cultural determinants of familial resemblance for plasma lipids and lipoproteins
Authors: Namboodiri K. K. , Kaplan E. B. , Heuch I. , Elston R. C. , Green P. P. , Rao D. C. , Laskarzewski P. , Glueck C. J. , Rifkind B. M. , Skolnick M. H.
Published: June 2005

This paper reports on the biological and cultural determinants of total, LDL, and HDL cholesterol, and triglyceride (TC, LDL‐C, HDL‐C, TG) levels using a general linear model on randomly selected family data collected during 1975–1978 at nine North American Lipid Research Clinics. Initially, the analyses were clinic‐specific to assess the importance of genetic and cultural transmission, marital resemblance, and other determinants of these traits and then were made jointly to identify the nature and sources of any heterogeneity between clinics. There was evidence of significant genetic and cultural factors for all traits in most clinics. Clinic heterogeneity was also significant, but excluding one clinic reduced the heterogeneity considerably. The genetic (h2) and cultural (c2) heritabilities for the remaining eight clinics were homogeneous with pooled estimates of h2 of .556 ± .028, .539 ± .028, .485 ± .029, and .358 ± .028, and of c2 of .029 ± .006, .033 ± .006, .075 ± .008, and .089 ± .009 for TC, LDL‐C, HDL‐C, and TG, respectively. Among the traits, HDL‐C exhibited the most difference among clinics, and both HDL‐C and TG showed the largest cultural heritability. The relevance of these and similar studies in a broader understanding of the determinants of plasma lipids and lipoproteins is discussed.
Familial analysis of qualitative traits under multifactorial inheritance
Authors: Rice John , Reich Theodore , Elston R. C.
Published: June 2005

The analysis of family data is described for qualitative multifactorial traits. For such a trait, affectational status is determined by an underlying liability distribution with one or more thresholds. The distribution of families (either selected at random or through probands) is used to estimate sex‐specific parent‐offspring and sibling correlations in liability and the prevalence in each sex. In contrast to using pairs of relatives, this approach permits estimation of age‐specific population prevalences without a control sample. Moreover, by allowing for sex‐specific correlations and a correlation between mates, path analysis can be used to model and test various cultural transmission models in addition to polygenic inheritance. Parameter estimation, hypothesis testing, and a goodness‐of‐fit test for path analytic models are described, and a computer program implementing these procedures is outlined.
The information content of phase‐known matings for ordering genetic loci
Authors: Timothy Bishop D. , Rao D. C.
Published: June 2005

This analysis evaluates the amount of linkage information that can be obtained for ordering three loci. The information contents of data collected on three independent pairwise samples of two loci, and data obtained jointly from three loci in a single set of individuals are compared. The level of support of the maximum likelihood order and the interpretation of that support are also examined.
Segregation analysis of hereditary nonpolyposis colorectal cancer
Authors: Bailey‐Wilson Joan E. , Elston Robert C. , Schuelke Guy S. , Kimberling William , Albano William , Lynch Jane F. , Lynch Henry T. , Rao D. C.
Published: June 2005

Segregation analysis of eleven families comprising 2762 individuals indicated compatibility of the data with segregation of a major autosomal dominant gene for hereditary nonpolyposis colorectal cancer. It was estimated that between 71% and 79% of the gene carriers were susceptible and had age of onset that was normally distributed with mean about 47 and standard deviation about 10 years. There was a low frequency of sporadic cases at the older ages, a little less than four percent of nongene carriers being affected by age 80. No significant differences were found between the families exhibiting endometrial cancer (cancer family syndrome) and those not exhibiting endometrial cancer (hereditary site‐specific nonpolyposis colonic cancer).
Testing for familial aggregation of a dichotomous trait
Authors: Hunt Steven C. , Hasstedt Sandra J. , Williams Roger R. , Rao D. C.
Published: June 2005

Familial aggregation of a disease is usually tested using a chi square statistic on a sample of pairs of related individuals. Standard sampling designs often produce dependent observations (multiple pairs from the same family), possibly inflating the numerical value of the statistic over the value independent observations would produce. This article presents a derivation of the chi square statistic for familial aggregation, allowing for dependency because of the inclusion of the same and related persons in multiple pairs. For intraclass aggregation, the standard chi square statistic is appropriate. For interclass aggregation, an adjustment to the standard chi square statistic is needed; the adjustment depends on the disease frequency and the intraclass aggregation within each class.
Heritability of clinical chemistries in an older twin cohort: The NHLBI Twin Study
Authors: Kalousdian Sona , Fabsitz Richard , Havlik Richard , Christian Joe , Rosenman Ray , Rao D. C.
Published: June 2005

Heritability analyses were performed with clinical chemistry data collected on 360 twin pairs of white, middle‐aged male veterans during the second examination of the NHLBI Twin Study, a multicenter study of cardiovascular disease risk factors. Significant genetic variability was present for albumin, alkaline phosphatase, blood urea nitrogen, 1‐hr postload glucose, phosphorus, total protein, and uric acid. Calcium and aspartate aminotransferase had significantly different means by zygosity, which precluded further analysis. Total bilirubin and lactate dehydrogenase did not show evidence for genetic variation at this examination. Comparisons are made to results from similar twin studies and the first examination of the NHLBI Twin Study. Heritability estimates for phosphorus and blood urea nitrogen exhibited marked stability across studies, while heritability estimates for total bilirubin, total protein, and uric acid decreased in older study populations. The heritability of 1‐hr postload blood glucose decreased from 0.88 at the first NHLBI examination to 0.52 at the second one. Interpretation of these results requires consideration of possible selection biases, methodologic and demographic issues, and the view that for some clinical chemistries, biological aging along with prolonged environmental exposures may alter the amount of phenotypic variation explained by the additive effect of genes alone.
Genetic epidemiology of myotonic dystrophy
Authors: Mostacciuolo M. L. , Barbujani G. , Armani M. , Danieli G. A. , Angelini C. , Rao D. C.
Published: June 2005

Prevalence rate of myotonic dystrophy (DM) was estimated in a large sample of the Italian population. Segregation analysis of the affected families suggests that subjects showing minor clinical signs, even in the absence of myotonic features, should be considered as bearers of the DM trait. An apparent excess of normal sibs among the offspring of DM subjects may be due to the late onset of the disease and possibly to a partial loss of affected individuals from the sample before diagnosis. Prevalence rate of DM in this study is estimated between 69 to 90 per million inhabitants; accordingly, DM might be the most frequent inherited neuromuscular disorder in human populations.
Age and prevalence of sickle‐cell trait in a large ambulatory population
Authors: Castro Oswaldo , Rana Sohail R. , Bang Ki Moon , Scott Roland B. , Rao D. C.
Published: June 2005

We performed hemoglobin electrophoresis in 30,400 apparently healthy black individuals in the Washington D.C. Metropolitan area, who were participating in a community based sickle‐cell screening program during the period 1978–1985. The overall prevalence of sickle‐cell trait was 6.7%. The frequency of sickle‐cell trait in various age groups, which included young children, adults, and individuals over 65 years of age, ranged from 6.4 to 7.4%. There were no statistically significant differences in the prevalence of sickle‐cell trait among the various age groups, nor did we detect a significant trend for increasing or decreasing sickle cell frequency with advancing age (P = 0.418). Thus, in this population sickle‐cell trait appears to have no effect on longevity. If the various complications of sickle‐cell trait reported in the literature are not fortuitous, their frequency and/or severity must be too low to affect prevalence figures.
Sex differences in affective disorder: Genetic transmission
Authors: Faraone Stephen V. , Lyons Michael J. , Tsuang Ming T. , Rao D. C.
Published: June 2005

Epidemiological studies have consistently found women to be at greater risk than men for affective disorders. This sex effect may help clarify genetic transmission and heterogeneity. Data from eight family studies of unipolar and eight family studies of bipolar probands were used to calculate family resemblance sex ratios. These observed sex ratios were then compared to sex ratios predicted by X‐linked and nonfamilial effects models. Maximum likelihood estimation of competing models revealed that X linkage was not a good fit to the unipolar data. The bipolar studies were not consistent with either the X‐linked or the nonfamilial effects model.
Path analysis of seven fear factors in adult twin and sibling pairs and their parents
Authors: Phillips Kay , Fulker David W. , Rose Richard J. , Eaves Lindon J.
Published: June 2005

A multivariate path model of genetic and environmental transmission, used to derive expected covariances among adult twin and sibling pairs and their parents, was fitted to fear factor data from 250 twin families and 91 sibling families, with the use of a maximum‐likelihood estimation procedure. The full model, with 259 free parameters, provides for parental cultural transmission, common twin and sibling environment, genotype‐environment correlation, direct assortative mating, and genetic and environmental correlations. Significant effects were indicated for heritable transmission of common fears and phobias, and a single genetic factor accounted for most of the genetic covariance among the traits. Moderately high levels of common twin environment and a small effect for direct isomorphic marital assortment were also found. There was no evidence for cultural transmission, genotype‐environment correlation, or common sibling environment.