Fertility and pacification among the mekranoti of Central Brazil

Demographers and anthropologists have recently turned their attention to the fertility increases that seem to have occurred with the “demographic transition.” This study examines various explanations for historical changes infertility among the Mekranoti-Kayapo Indians of Central Brazil. Data from pregnancy histories and genealogies suggest that changes in health status, use of contraceptives, lactation periods, and post-partum sexual abstinence are not as important in accounting for Mekranoti fertility as is warfare. Because of high male mortality from war, many Mekranoti women spent a large portion of their reproductive years without a husband, and their fertility was significantly lower as a result. This finding may have implications for demographic changes elsewhere and in other periods of human evolution.     

Marital Structure,Genetic Fitness,and the <Emphasis Type="Italic">GJB2</Emphasis> Gene Mutations among Deaf People in Yakutia (Eastern Siberia,Russia)

Autosomal recessive deafness type 1A (DFNB1A) caused by mutations in the GJB2 gene (Cx26) is the main cause of nonsyndromic hearing impairment in many populations worldwide. It is considered that widespread prevalence of DFNB1A can be due to the long tradition of intermarriages between deaf people (assortative marriages) combined with their increased social adaptation and genetic fitness after widespread introduction of sign language. For the first time, the data on mating structure and reproduction of deaf people living in Yakutia (Eastern Siberia, Russia) are presented in comparison with contribution of the GJB2 gene mutations to the etiology of hearing impairment. The relative fertility of deaf people compared to their hearing siblings is 0.78 (mean number of children 1.76 ± 0.10 and 2.24 ± 0.09 to deaf and their hearing siblings, respectively, p = 0.0018). The rate of assortative marriages among deaf people is 77.1% (81 of 105 marriages). Biallelic mutations in the GJB2 gene were found in 42.2% (43 of 102) of examined deaf people, which corresponded to diagnosis DFNB1A for these patients. A comparison of deaf marital partners by GJB2 status revealed a proportion of noncomplementary marriages (24%) in which hearing loss in both partners was caused by the presence of biallelic GJB2 gene mutations resulting in the birth of only deaf children in such couples. Thus, the set of obtained data including a relatively high genetic fitness (expressed as relative fertility) of deaf people in Yakutia in combination with a high rate of assortative marriages among them and high incidence of DFNB1A indicates a possible weakening of selection against such trait as “deafness” and a possible increase in the frequency of GJB2 mutant alleles in subsequent generations.     

THE ECOLOGY AND GENETICS OF FITNESS IN CHLAMYDOMONAS III. GENOTYPE-BY-ENVIRONMENT INTERACTION WITHIN STRAINS

The fitness of genotypes created by crossing strains of Chlamydomonas reinhardtii was measured in axenic pure culture in a set of chemically defined environments. There was substantial and highly significant genotype-by-environment interaction, with genetic correlations between environments averaging only about +0.1 for both r and K. Higher-order interactions with combinations of environmental factors appeared to be no less important than simple interactions with single factors. The importance of genotype-by-environment interaction increased with the number of environmental factors manipulated. The linear reaction norms of genotypic score on environmental mean score varied substantially among genotypes and often intersected. There was also some evidence that nonallelic genetic interactions were present, and varied among environments. The genetic correlation of r with K also varied among environments, being significantly negative in some but not in others. These results are similar in all important respects to those previously obtained with different species, and suggest that genotype-by-environment interaction is important at all genetic scales. It is argued that they provide empirical support for a general theory of diversity, the “Tangled Bank,” based on the different response of genotypes to the range of conditions found in heterogeneous natural environments.     

Effects of cyclic spouse separation on conception times

The lengthening of conceptive delays under conditions of natural fertility by cyclic spouse separation is investigated as a problem in renewal processes. Separations are “complete” if they reduce the conditional monthly probability of conception, or fecundability, to zero, and “incomplete” if they merely reduce it, from f to r say. Earlier work respecting cyclic separation by Menken (1979) is extended with formulas for the mean and variance of conceptive delays conditional on T, the ordinal month of the cycle of separation and nonseparation when the woman passes from anovulation into the fecundable state. A simple expression relating fecundabilities f and r and the conditional proportions P_s(T) and P_s-(T) conceiving during separation and nonseparation is obtained.     

Fecundity,developmental time,and population growth rate: An analytical solution

Population growth rate is affected by both developmental time and net fecundity, and we have investigated the relative importance of these two factors. Simple analytical expressions, derived for both discrete and continuous models, show that the increase in fecundity required to duplicate the effect of a unit shift in development is directly proportional to population growth rate and inversely proportional to survival rates. Our analysis requires no assumptions about the form of the maternity or survivorship functions. While these results agree well with the widely held notion that “r-selection” favors fast development time, they generate the somewhat paradoxical prediction that “K-selection” should favor high reproductive output. The resolution of this problem probably involves constraints not included in most current analyses.     

Child Mortality Estimation: Consistency of Under-Five Mortality Rate Estimates Using Full Birth Histories and Summary Birth Histories

Background

Given the lack of complete vital registration data in most developing countries, for many countries it is not possible to accurately estimate under-five mortality rates from vital registration systems. Heavy reliance is often placed on direct and indirect methods for analyzing data collected from birth histories to estimate under-five mortality rates. Yet few systematic comparisons of these methods have been undertaken. This paper investigates whether analysts should use both direct and indirect estimates from full birth histories, and under what circumstances indirect estimates derived from summary birth histories should be used.

Methods and Findings

Usings Demographic and Health Surveys data from West Africa, East Africa, Latin America, and South/Southeast Asia, I quantify the differences between direct and indirect estimates of under-five mortality rates, analyze data quality issues, note the relative effects of these issues, and test whether these issues explain the observed differences. I find that indirect estimates are generally consistent with direct estimates, after adjustment for fertility change and birth transference, but don''t add substantial additional insight beyond direct estimates. However, choice of direct or indirect method was found to be important in terms of both the adjustment for data errors and the assumptions made about fertility.

Conclusions

Although adjusted indirect estimates are generally consistent with adjusted direct estimates, some notable inconsistencies were observed for countries that had experienced either a political or economic crisis or stalled health transition in their recent past. This result suggests that when a population has experienced a smooth mortality decline or only short periods of excess mortality, both adjusted methods perform equally well. However, the observed inconsistencies identified suggest that the indirect method is particularly prone to bias resulting from violations of its strong assumptions about recent mortality and fertility. Hence, indirect estimates of under-five mortality rates from summary birth histories should be used only for populations that have experienced either smooth mortality declines or only short periods of excess mortality in their recent past. Please see later in the article for the Editors'' Summary.     

Species and “strange species” in zoology: Do we need a “unified concept of species”?

Eidonomy is the field of taxonomy, which addresses the “species problem”. The latter has several dimensions. The first is the confusions frequently made between species as an evolutionary unit, a taxon, a taxonomic category and a nomenclatural rank. The second is the reductionist temptation to recognize in nature only one kind of “basic entities” of biodiversity. From a practical viewpoint and for all non-systematist users of specific nomina, any animal organism should be referred to a taxon of nomenclatural rank species, designated by a Latin binomen. These nomina are indispensable for administrative and legal documents, for management and conservation of biodiversity, as well as for all biological research. But this does not imply that all these taxa should be referred to a single taxonomic category, a “unified concept of species”. In nature, several kinds of entities correspond to different “species concepts” or specions that are irreducible one to another. These categories can be defined according to the modalities of their reproduction, i.e., of their gametopoiesis (mode of formation of gametes), of their kinetogenesis (mode of initiation of the development of the ovum) and of the gene flow between individuals. The best known of these categories is that of mayron or “mixiological species concept”, which points to an independent bisexual panmictic entity, constituting a protected gene pool, but others do exist. In order to better understand their differences, it is useful to consider the various patterns of speciation. These can be referred to three main categories: monogeny (change within a single lineage), diplogeny (birth of two specions from a single one) and mixogeny (hybridization between two specions). The splitting in two of a single initial gene pool is a rather long process, which often shows different stages. The latter can be expressed taxonomically through the use of particular eidonomic categories. Speciation can be considered completed only when it has become irreversible in case of new contact between the two stocks after a period of separation. In allopatry, it is difficult or impossible to know if this stage has been reached. This is not a reason for abandoning the mixiological criterion for identifying sympatric or parapatric specions. In allopatry, the method of inference can be used and, in the absence of sufficient information, it is fully possible to use “by default” the “phylogenetic concept of species” or simpson. The situation is further complicated by the fact that some of the basic entities of biodiversity of hybrid origin, the kyons, are not mayrons, as they have particular reproductive modes. Contrary to isolated and “normal” hybrids, such entities may persist in the long term in nature. Their gametopoiesis implies either an ameiosis (mitoses) or a metameiosis (modified meiosis), and their kinetogenesis implies zygogenesis (fertilization), gynogenesis or parthenogenesis. Kyons are of two main categories. The klonons are unisexual female entities in which genetic transmission is clonal, reproduction being often through parthenogenesis, or following other mechanisms with similar results in genetic terms. The kleptons are unisexual or bisexual entities, which depend for their reproduction, at each generation, on a mayron or another klepton. Their metameiosis produces particular gametes, which start their development either by zygogenesis (zygokleptons), by gynogenesis (gynokleptons) or by a combination of both systems (tychokleptons). All these particular cases do not constitute, as it has long been believed, “evolutionary dead ends”. On the contrary, some of these forms are advantaged in some conditions, and may also, in some cases, be at the origin of allopolyploid specions. The latter include both “normal mayrons” or eumayrons (allotetraploid bisexual entities) and heteromayrons (allotriploid bisexual entities with metameiosis). Mayron, klepton, klonon and simpson, and their subcategories, are different taxonomic categories which correspond to a single nomenclatural rank, that of species. The existence of interspecific hybridization in nature is a very common phenomenon in animals, the importance of which has long been underestimated. Reticulous relationships between specions have played a major role in the scenario of evolution. This should be acknowledged by the rejection of the “universal tree of life” model for organic evolution and its replacement by a “network of life” model.     

The allometric interpretation of the self-thinning rule

Plant populations growing at high densities undergo density-dependent mortality or self-thinning. The density of survivors ({ρ}) is related to their mean biomass (w) by the power equation w = K_ρ^?a, where a is $\text{3}\text{2}$. This is known as the “self-thinning rule”. This relationship is very general for plant populations and represents both an asymptotic time-trajectory for a particular population and a boundary line for juxtaposed joint values of w and p of separate populations. The traditional allometric derivation of the rule is outlined and shown to be unrealistic. An attempt to reformulate the self-thinning rule, based on the traditional allometric derivation, is shown to be unsatisfactory and an alternative allometric derivation is presented. The rule in its traditional statement $\text{w = K}{}_{\mathrm{\rho }}{}^{\mathrm{?3}}\text{2}$ is still its best expression. The nature of the constant K is discussed with particular reference to its dimensionality.     

Race differences and r/K theory: A reply to Silverman

To allow an adequate evaluation of r/K theory in light of Silverman's critique, data are tabulated showing that, on average, Mongoloids > Caucasoids > Negroids in brain size and intelligence, maturational delay, sexual restraint, quiescent temperament, and social organization. The sequence of this suite of life-history characters may parallel the order of emergence of the populations in earth history. The phased linearity is ordered by a theory of r/K reproductive strategies in which Mongoloids are more K selected than Caucasoids and especially more than Negroids. It is suggested that behavioral differences among human races arose because the more predictable environment faced by later emerging populations selected for increased brainsize, fewer and slower maturing offspring, greater parental care per each offspring, stronger pair bonds, and increased social organization.     

Effect of several “specific” chemical reagents on the Na+, K+ and leakage currents in voltage-clamped single nodes of ranvier

The magnitude of the Na⁺, K⁺ and leakage currents through voltage-clamped single nodes of Ranvier of the frog versus time were monitored with the aid of a computer as the node was perfused with one of the following “specific” chemical reagents in an appropriate Ringer's solution: six enzymes, N-bromosuccinimide, N-ethyl- N′-(3-dimethylaminopropyl)-carbodiimide methiodide, tetranitromethane, N-ethylmaleimide, NaIO₄, NaIO₃, and sodium cyanoborohydride.While the enzymes examined showed little effect on the ionic currents several of the other reagents permanently altered selectively the K⁺ current, leading to the tentative conclusion that accessible SH groups are more important to the operation of the K⁺ mechanisms than to the Na⁺ mechanisms. With some reagents the leakage current suddenly increased dramatically while the Na⁺ and K⁺ mechanisms were still functioning “normally”, though at reduced levels. Accessible iminium or enamine linkages or 1,2-dihydroxy groupings may be modified if present, without profound effects on the ionic currents. Some experimental basis is provided for the possibility that not all “channels” of a particular ion are chemically alike.     

Statistical Description of Food Microstructure. Extraction of Some Correlation Functions From 2D Images

Two algorithms able to compute lineal-path distribution function L(z) and two-point correlation function, S ₂ (r ₁ ,r ₂ ) from 2D digital images of foods were developed and validated. Particularly, “Altamura” and “White” breads as well as “Napoli” sausages were studied. Lineal-path function was modeled by considering the foods as two-phase random systems composed from polydisperse overlapping disks. Instead, two-point correlation function was modeled by using a Debye’s equation. In all cases a good agreement between experimental and theoretical trend was obtained stating the high accuracy of the algorithms in the extraction of correlation functions as well as the possibility to model breads and sausages as two-phase random systems. Also, important morphological properties such as pores distribution, pore size homogeneity and their spatial distribution, were obtained. For instance, although the estimated radius of the pores was lower for “Altamura” bread rather that for “White”, its slowest decay of L(z) highlighted that the pores showed a high dimensional inhomogeneity.     

Morphological and genetic characteristics of genetic tumor in Nicotiana glauca

It is well understood that genetic tumors develop in certain interspecific Nicotiana hybrids. Nicotiana species are divided into “plus” and “minus” groups and crosses between “plus” and “minus” species give rise to tumorous hybrids. However, it has been proposed that parents and hybrids derived from crosses among members within the same group do not produce tumors. In this study, genetic tumors were only obtained in Nicotiana glauca, which exhibited tumor features similar to those of N. glauca × N. langsdorffii. Our results suggest that genetic factors may control tumor formation independent of tumor induction dependent on the specific interspecific cross. Genetic tumor formation exhibited high B-type and D-type cyclin expression levels, indicating tumor cells are characterized by an uncontrolled cell cycle.     

The change of life,the sorrow of life: Menopause,bad blood and cancer among Italian-Australian working class women

This paper explores the discourse of menopause, health and illness among 20 middle aged Italo-Australian working class women living in Melbourne. Using the methods of interpretative anthropology and the perspectives of critical feminist theory, I argue that women's discourse about health and illness is one way in which they express feelings of loss over the fertility of their youth, ambivalences about their lives in Australia, and grief over a life left behind in Italy. These losses are experienced physically and expressed metaphorically through conditions of bad blood and nerves and are perceived to contribute to their vulnerability to a range of diseases including cancer. For these women, the change of life is experienced as the end of life and their fear of cancer is representative of their fears of social and physical death. Cancer is also seen to be a disease more common in Australia and is used as a metaphor for expressing anxieties relating to feelings of placelessness, of being disconnected from one's roots, and anxieties about becoming old and dying far from “home.”     

Child wellbeing and income inequality in rich societies: ecological cross sectional study

Objectives To examine associations between child wellbeing and material living standards (average income), the scale of differentiation in social status (income inequality), and social exclusion (children in relative poverty) in rich developed societies.Design Ecological, cross sectional studies.Setting Cross national comparisons of 23 rich countries; cross state comparisons within the United States.Population Children and young people.Main outcome measures The Unicef index of child wellbeing and its components for rich countries; eight comparable measures for the US states and District of Columbia (teenage births, juvenile homicides, infant mortality, low birth weight, educational performance, dropping out of high school, overweight, mental health problems).Results The overall index of child wellbeing was negatively correlated with income inequality (r=−0.64, P=0.001) and percentage of children in relative poverty (r=−0.67, P=0.001) but not with average income (r=0.15, P=0.50). Many more indicators of child wellbeing were associated with income inequality or children in relative poverty, or both, than with average incomes. Among the US states and District of Columbia all indicators were significantly worse in more unequal states. Only teenage birth rates and the proportion of children dropping out of high school were lower in richer states.Conclusions Improvements in child wellbeing in rich societies may depend more on reductions in inequality than on further economic growth.     

Y Chromosomal Variation Tracks the Evolution of Mating Systems in Chimpanzee and Bonobo

The male-specific regions of the Y chromosome (MSY) of the human and the chimpanzee (Pan troglodytes) are fully sequenced. The most striking difference is the dramatic rearrangement of large parts of their respective MSYs. These non-recombining regions include ampliconic gene families that are known to be important for male reproduction,and are consequently under significant selective pressure. However, whether the published Y-chromosomal pattern of ampliconic fertility genes is invariable within P. troglodytes is an open but fundamental question pertinent to discussions of the evolutionary fate of the Y chromosome in different primate mating systems. To solve this question we applied fluorescence in situ hybridisation (FISH) of testis-specific expressed ampliconic fertility genes to metaphase Y chromosomes of 17 chimpanzees derived from 11 wild-born males and 16 bonobos representing seven wild-born males. We show that of eleven P. troglodytes Y-chromosomal lines, ten Y-chromosomal variants were detected based on the number and arrangement of the ampliconic fertility genes DAZ (deleted in azoospermia) and CDY (chromodomain protein Y)—a so-far never-described variation of a species'' Y chromosome. In marked contrast, no variation was evident among seven Y-chromosomal lines of the bonobo, P. paniscus, the chimpanzee''s closest living relative. Although, loss of variation of the Y chromosome in the bonobo by a founder effect or genetic drift cannot be excluded, these contrasting patterns might be explained in the context of the species'' markedly different social and mating behaviour. In chimpanzees, multiple males copulate with a receptive female during a short period of visible anogenital swelling, and this may place significant selection on fertility genes. In bonobos, however, female mate choice may make sperm competition redundant (leading to monomorphism of fertility genes), since ovulation in this species is concealed by the prolonged anogenital swelling, and because female bonobos can occupy high-ranking positions in the group and are thus able to determine mate choice more freely.     

Applying socioendocrinology to evolutionary models: Fatherhood and physiology

Owing to humans' unique life history pattern, particularly comparatively short interbirth intervals, early weaning, and prolonged support of multiple dependents, human females have greater reproductive value and higher lifetime fertility, on average, than do their Great Ape counterparts. 1 - 4 As hominin females began weaning their young early and “stacking” dependents of various ages, they must have had cooperative allomaternal care partners already in place or been successful at concurrently soliciting help to ensure a high rate of survival of their offspring. 1 - 6 Following Hrdy, I define allomaternal care (and its derivatives, such as “allomothers” and “allomothering”) as “care from anyone other than the mother,” which thus encompasses a wide range of individuals, including fathers. 7 Who the likely allomother candidates mothers were and what form that cooperation took remain intriguing, difficult‐to‐answer questions, which are limited, in some capacity, by the lines of evidence available to us. Here, I present a framework for the ways in which we can integrate neurobiological‐endocrine and social‐behavioral data (“socioendocrinology”) 8 to contribute to this dialogue in terms of evaluating fathers' roles.     

Pairs of Genetically Unrelated Look-Alikes

Relationships of physical resemblance to personality similarity and social affiliation have generated considerable discussion among behavioral science researchers. A “twin-like” experimental design (involving genetically unrelated look-alikes, U-LAs) explores associations among resemblance in appearance, the Big Five personality traits, self-esteem, and social attraction within an evolutionary framework. The Personality for Professionals Inventory (PfPI), NEO/NEO-FFI-3, Rosenberg Self-Esteem Scale, and a Social Relationship Survey were variously completed by 45 U-LA pairs, identified from the “I’m Not a Look-Alike” project, Mentorn Media, and personal referrals. The mean U-LA intraclass correlations were negligible for all Big Five personality traits on the PfPI and NEO/NEO-FFI-3 (r_i =??.02 and???.04, respectively). In contrast, mean r_i values of .53 and .15 for monozygotic (MZA) and dizygotic (DZA) reared-apart twins, respectively, have been reported for these personality measures. The U-LA self-esteem correlation (r_i =??.18) was also below the correlations reported for MZ and DZ reared-together twins (r_{i =} .31 and .13, respectively). Finally, far fewer U-LAs expressed close social relationships (20%) than MZA (80%) and DZA (65%) twins. The present study extends earlier findings indicating that appearance is not meaningfully related to personality similarity and social relatedness. The criticism that MZ twins are alike in personality because their matched looks invite similar treatment by others is refuted. A more judicious interpretation is reactive genotype-environment correlation, namely that MZ twins’ similar personalities evoke similar reactions from others. MZ twins’ close social relations most likely derive from their perceptions of genetically based within-pair similarities that are lacking in U-LAs.     

Reproductive phenology and biology in annual and perennial Alismataceae

Two annual (Echinodorus rostratus (Nutt.) Engelm., Sagittaria calycina Engelm.) and 3 perennial (Alisma subcordatum Rat., S. brevirostra Mack & Bush, S. latifolia Wild.) species of Alismataceae were compared to determine differences in reproductive effort and timing. The annuals produce flowers and fruits earlier and later than the perennials and, under optimal conditions, the annuals also produce more (but smaller) seeds annually per plant. Populations of the annuals occur on exposed mud and are erratically abundant from year to year, while populations of the perennials are more stable. Seed viability of the annuals decreases more slowly over time. There is general congruence of these life-history attributes with the concepts of “r” and “K” strategies.