Directional asymmetry of finger ridge counts in females of Sardinian linguistic groups

The data used in this study are the fingerprints of 744 females from 6 Sardinian linguistic groups. We analyzed 15 dermatoglyphic variables of directional asymmetry, namely the right vs left signed differences between i-th homologous fingers for larger ridge counts, radial counts and ulnar counts. Principal components analysis of the dermatoglyphic variables in the females of Sardinian linguistic groups revealed a pattern of biological relations among the groups which is consistent with their linguistic, but especially historical and demographic, backgrounds.     

Quantitative characterization of finger and palm dermatoglyphics in Bulgarians

In the present paper data on finger and palm ridge counts of both hands are reported from representative samples of healthy Bulgarian males and females. Dermatoglyphic prints from both hands of 2431 Bulgarians (1161 males and 1270 females) have been taken in 116 settlements all over the country. The investigated males and females were healthy, not related persons of Bulgarian origin. The results of finger and palm ridge counts include basic statistics and correlations between ridge counts on separate fingers and the correlations between ridge counts in separate interdigital areas. The results, presented together with data on other dermatoglyphic features elaborated and published till now by the same authors for representative samples of Bulgarian males and females, can serve for the set up of a detailed data basis of the dermatoglyphic status of the Bulgarian population. At the same time they could serve as a norm for clinical and medico-biological investigations with theoretical and scientific applied purposes.     

Sexual dimorphism in dermatoglyphic traits and fluctuating asymmetry in Bulgarians from northeast Bulgaria

In parallel with the development of dermatoglyphics as a method of identification, data have been accumulated on the characteristics of fingerprints related to sex and ethnic origin which make up the statistical basis of this study. The aims of the present study are to determine phenotype variations in the asymmetry of dermatoglyphics in both sexes within the scope of the entire hand skin ridge system; to investigate correlations between the phenotypes; and, to assess the fluctuating asymmetry among the Bulgarian population from the region of northwest Bulgaria. The sample consists of 894 unrelated, clinically healthy individuals (480 females and 414 males) aged 18–50 years, who live in towns and villages in the northwest provinces.Finger and palmar prints were collected using rolled print (inked) method. Twenty dermatoglyphics variables of fingers and hands, separately for right and left hands and jointly for both hands, were statistically assessed. The material was processed by SPSS 12 software. The results of the present study show distinctive sexual differences. Higher values in males are recorded in finger ridge counts, the Furuhata and Cummins indices, the palm ridge counts and the overall ridge counts in all interdigital areas. Males have higher frequency values in patterns Hy, Th/III and Th/IV.     

Digital ridge counts and genetic fields

Summary Principal components analysis of quantitative digital dermatoglyphics in a large Oxfordshire sample, subdivided into male, female, urban, and rural subsamples, suggests several distinguishable components. These appear meaningful biologically in that they resemble factors of limb growth, as suggested by evidence from disturbances in limb extremity development. The components are consistent in all four subsamples and are very similar to those identified in a large sample of Berkshire data. It is suggested that digital quantitative dermatoglyphic variation may provide an example of genetic field theory.     

家族性耳聋者的掌纹嵴数

本文测量了耳聋患者的a-b,a-d和td纹嵴数,并比较了各个患者的皮纹学差异。资料收集自印度Punjabi Khatri和Arora地区的208名家族性遗传性耳聋者,其中男性118名;女性90名,对照组228名Punjabi地区正常人,其中男性128名,女性100名,本研究表明,与对照组相比,耳聋组的‘a-b’,‘a-b’和‘td’纹嵴数偏低。     

Genetics of plantar interdigital ridge counts

The genetics of interdigital ridge counts of soles has been studied in a homogeneous Brahmin population of Andhra pradesh, India. The parameters considered are a-b, b-c and c-d ridge counts. A new measure - total plantar interdigital ridge counts (TPtIRC) - has been defined and an attempt has been made to evaluate the mode of inheritance of this trait. The results of the present study do not fully support the earlier conclusions regarding the genetics of a-b, b-c and c-d ridge counts.     

Mechanisms of directional asymmetry in the zebrafish epithalamus

The epithalamus of zebrafish presents the best-studied case of directional asymmetry in the vertebrate brain. Epithalamic asymmetries are coupled to visceral asymmetry and include left-sided migration of a single midline structure (the parapineal organ) and asymmetric differentiation of paired bilateral nuclei (habenulae). The mechanisms underlying the establishment of epithalamic asymmetry involve the interplay between anti-symmetry and laterality signals to guide asymmetric parapineal migration. This event triggers the amplification of habenular asymmetries and the subsequent organisation of lateralised circuits in the interpeduncular nucleus. This review will summarise our current understanding on these processes and propose a sequential modular organisation of the events controlling the development of asymmetry along the parapineal–habenular–interpeduncular axis.     

Mixture analysis of asymmetry: modelling directional asymmetry, antisymmetry and heterogeneity in fluctuating asymmetry

The occurrence of different forms of asymmetry complicates the analysis and interpretation of patterns in asymmetry. Furthermore, between-individual heterogeneity in developmental stability (DS) and thus fluctuating asymmetry (FA), is required to find relationships between DS and other factors. Separating directional asymmetry (DA) and antisymmetry (AS) from real FA and understanding between-individual heterogeneity in FA is therefore crucial in the analysis and interpretation of patterns in asymmetry. In this paper we introduce and explore mixture analysis to (i) identify FA, DA and AS from the distribution of the signed asymmetry, and (ii) to model and quantify between-individual heterogeneity in developmental stability and FA. In addition, we expand mixtures to the estimation of the proportion of variation in the unsigned FA that can be attributed to between-individual heterogeneity in the presumed underlying developmental stability (the so-called hypothetical repeatability). Finally, we construct weighted normal probability plots to investigate the assumption of underlying normality of the different components. We specifically show that (i) model selection based on the likelihood ratio test has the potential to yield models that incorporate nearly all heterogeneity in FA; (ii) mixtures appear to be a powerful and sensitive statistical technique to identify the different forms of asymmetry; (iii) restricted measurement accuracy and the occurrence of many zero observations results in an overestimation of the hypothetical repeatability on the basis of the model parameters; and (iv) as judged from the high correlation coefficients of the normal probability plots, the underlying normality assumption appears to hold for the empirical data we analysed. In conclusion, mixtures provide a useful statistical tool to study patterns in asymmetry.     

Path analysis of palmar ridge counts.

The methods for path analysis of family resemblance (Rao et al., '74) are employed to test hypotheses concerning the inheritance of a-b, b-c and c-d palmar ridge counts using the correlation data of Pateria ('74). Homogeneity chi-square tests of the various familial correlations provide no evidence for sex-linkage of either kind, and also suggest that maternal effects are absent. The path coefficient model employed here involves heritability (additive) and common sibling environment. Variance components show that both heritability and common environment are significant, and account for most of the variation at each of the three ridge count area; b-c has the highest heritability, significantly higher than that for a-b or c-d.     

Diversity of palmar pattern ridge counts in Iranian populations

We analyzed bilateral palmar prints of 3,158 individuals from 13 Iranian populations of diverse origins for palmar pattern ridge counts. Right palms did not show greater counts than the left in the majority of the populations studied. Highly significant interpopulational variation was observed for most palmar areas of both males and females. Dendrograms of males and combined sexes showed a good fit with the ethnohistoric background of the populations studied. The results thus demonstrate variation in the palmar pattern ridge counts of populations of diverse origins and may be used as a good measure of population distance.     

Population variation in asymmetry and diversity from finger to finger for digital ridge-counts

Population variation in ridge-count asymmetry and diversity from finger to finger has received scant attention in dermatoglyphic studies. Asymmetry, in particular, has generally been attributed to environmental effects operating during the formation of dermal ridges. Examination of samples from several groups of diverse racial background revealed the existence of considerable population variation with respect to finger ridge-count asymmetry and diversity from finger to finger. Patterning along population lines suggests a genetic rather than environmental basis for such variation. The genetic mechanisms responsible for ridge-counts may also mediate asymmetry and diversity, or the degree of developmental stability in different populations may itself be under genetic control.     

Antisymmetry,directional asymmetry,and dynamic morphogenesis

Fluctuating asymmetry is the most commonly used measure of developmental instability. Some authors have claimed that antisymmetry and directional asymmetry may have a significant genetic basis, thereby rendering these forms of asymmetry useless for studies of developmental instability. Using a modified Rashevsky-Turing reaction-diffusion model of morphogenesis, we show that both antisymmetry and directional asymmetry can arise from symmetry-breaking phase transitions. Concentrations of morphogen on right and left sides can be induced to undergo transitions from phase-locked periodicity, to phase-lagged periodicity, to chaos, by simply changing the levels of feedback and inhibition in the model. The chaotic attractor has two basins of attraction-right sidedominance and left side dominance. With minor disturbance, a developmental trajectory settles into one basin or the other. With increasing disturbance, the trajectory can jump from basin to basin. The changes that lead to phase transitions and chaos are those expected to occur with either genetic change or stress. If we assume that the morphogen influences the behavior of cell populations, then a transition from phase-locked periodicity to chaos in the morphogen produces a corresponding transition from fluctuating asymmetry to antisymmetry in both morphogen concentrations and cell populations. Directional asymmetry is easily modeled by introducing a bias in the conditions of the simulation. We discuss the implications of this model for researchers using fluctuating asymmetry as an indicator of stress.     

Heredity and the bimanual asymmetry of human finger and palm dermatoglyphs

An attempt has been made to study the effect of hereditary factors on the asymmetry of morpho-functional quantitative traits, in particular, finger and palm dermatoglyphs (24 indices). The results of examination of 140 twin pairs (83 monozygotic and 57 dizygotic) are presented. The hereditary effects have been found for ten traits when an account is taken of the asymmetry direction, and for nine traits when asymmetry direction is not considered.     

On the adaptive accuracy of directional asymmetry in insect wing size

Subtle left-right biases are often observed in organisms with an overall bilateral symmetry. The evolutionary significance of these directional asymmetries remains uncertain, however, and scenarios of both developmental constraints and adaptation have been suggested. Reviewing the literature on asymmetry in insect wings, we analyze patterns of directional asymmetry in wing size to evaluate the possible adaptive significance of this character. We found that directional asymmetry in wing size is widespread among insects, with left- and right-biased asymmetries commonly observed. The direction of the asymmetry does not appear to be evolutionarily conserved above the species level. Overall, we argue that the very small magnitude of directional asymmetry, 0.7% of the wing size on average, associated with an extremely imprecise expression, precludes directional asymmetry from playing any major adaptive role.     

Genetic parameters of dermal patterns of ridge counts.

Dermatoglyphic traits including ridge counts and pattern type counts on fingers were studied in 711 families representing six racial groups in Hawaii. Heritability tesimates were derived from regressions of offspring on father, mother and mid-parent values as well as from full-sib correlations. These estimates varied from 0.23 for radial loops to 0.80 for total ridge count. The heritability estimates were lower for ridge counts of single hands or single digits.