Fixed and random effects in the variation of the finger ridge count: a study of fragile-X families.

A maximum-likelihood scoring technique for analysis of pedigree data allows for the concurrent estimation of random and of fixed effects in a quantitative trait. We included both types of effects in genetic models, to study the sources of variation in finger ridge count in 54 large families affected with the fragile-X disorder. The fixed effects were represented by fragile X and sex, and the random effects by environmental and genetic variance. We found a significant effect of fragile X in the mean of the finger ridge count on the thumb (finger 1) and index finger (finger 2), which had the lowest heritability and a negligible nonadditive component of genetic variance. This was in contrast with ridge counts on fingers 3 and 4, which showed little fragile-X effect, but high heritability and a significant nonadditive component. A contrast in genetic properties for ridge counts on fingers 1 and 2, compared with these counts on the remaining three fingers, may be relevant to increased selection pressures on functions of the thumb and of the index finger in evolution of modern man. We have also demonstrated an important effect of fragile X in increasing the additive variance in covariance, especially between male pairs. These findings suggest that the effect of the fragile-X genotype in finger ridge count is additive and superimposed on the normal hereditary variations in this trait.     

Inter-sex and intra-sex differences in quantitative digital dermatoglyphics of Sardinian-speaking groups

In this study, we analysed inter-sex differences within two linguistic groups from the Sardinian linguistic area and intra-sex differences between the two groups by means of 41 quantitative digital dermatoglyphic variables: 20 digital dermatoglyphic traits (radial and ulnar ridge counts on each of the 10 fingers), 15 digital dermatoglyphic directional asymmetry variables, total finger ridge count, bilateral summed radial and ulnar finger ridge counts, an index of asymmetry between homologous fingers, and two indices of intra-individual diversity of finger ridge counts. The comparisons between males and females within the same linguistic groups and between the males of the two groups and the females of the two groups were carried out with the Mann-Whitney test at a prefixed level of alpha = 0.05, using the Bonferroni correction for multiple comparisons. The results indicate a strong similarity of the two linguistic groups in the inter-sex differences, whereas there are no significant differences between them for either males or females. The similar pattern of sexual dimorphism and the homogeneity of the males and females of the two groups suggest a common genetic matrix of these Sardinian-speaking groups.     

Quantitative finger dermatoglyphics in a Spanish population (Tierra de Campos)

This study deals with the finger ridge counts and the distribution of their frequencies drawn from a Spanish sample consisting of 833 school-children (417 males and 416 females), which has been collected from the geographical area of Tierra de Campos. Paired t-test and Student-t-test were used to explore bimanual and sexual differences, respectively. The results showed: a bimanual asymmetry marked by significantly higher right hand ridge count for thumb and index pairs in both males and females, ridge counts of males are always higher than the corresponding values of females; the differences being significant excepting for right and left index and for left ring-finger. The frequency distribution of TFRC was slightly, but significantly, different from normality only in males, as Kolmogorov test showed. A great homogeneity between values for TFRC of males and females from Tierra de Campos and those of the available Spanish and Portuguese populations has been found, the values being high not only in the variation ranges of the Spanish and Portuguese populations, but also in the ranges reported for other European populations.     

Linkage analysis of a model quantitative trait in humans: finger ridge count shows significant multivariate linkage to 5q14.1

The finger ridge count (a measure of pattern size) is one of the most heritable complex traits studied in humans and has been considered a model human polygenic trait in quantitative genetic analysis. Here, we report the results of the first genome-wide linkage scan for finger ridge count in a sample of 2,114 offspring from 922 nuclear families. Both univariate linkage to the absolute ridge count (a sum of all the ridge counts on all ten fingers), and multivariate linkage analyses of the counts on individual fingers, were conducted. The multivariate analyses yielded significant linkage to 5q14.1 (Logarithm of odds [LOD] = 3.34, pointwise-empirical p-value = 0.00025) that was predominantly driven by linkage to the ring, index, and middle fingers. The strongest univariate linkage was to 1q42.2 (LOD = 2.04, point-wise p-value = 0.002, genome-wide p-value = 0.29). In summary, the combination of univariate and multivariate results was more informative than simple univariate analyses alone. Patterns of quantitative trait loci factor loadings consistent with developmental fields were observed, and the simple pleiotropic model underlying the absolute ridge count was not sufficient to characterize the interrelationships between the ridge counts of individual fingers.     

Maternal effects on fingertip dermatoglyphics.

Significantly larger variation between sibships within families of male MZ twins than between sibships within families of female MZ twins, indicative of maternal influences, was found for 10 of 41 dermatoglyphic fingertip variables. Of these, five were thumb-related with the effect primarily on the thumb radial and ridge count (larger of radial and ulnar count). These same variables were previously found to have unequal variances in MZ twins of known placental type, and the results indicate maternal influences in singletons as well as twins for these variables. Although the total ridge count (TRC), previously shown to differ in MZ twins of known placental type (paralleling the thumb radial and ridge counts) did not reach significance, the trend indicated that the observed thumb changes may be reflected in the TRC as well. Little finger pattern type and ulnar counts also showed less variability in families of female MZ twins, but the interpretation is complicated by the concomitant differences in mean squares within-sibships for these little finger variables.     

Variations on dermal ridges in nine population groups of maharashtra,india. III. Asymmetry and interdigital diversity

Variations in asymmetry and interdigital diversity for the three finger-dermatoglyphic traits, total finger ridge count (TRC), absolute total finger ridge count (ARC), and finger pattern intensity index (PII) have been studied here from a sample of 646 males belonging to nine population groups from Maharashtra, India. It is seen that at such local level of population differentiation the ridge count measures TRC and ARC discriminate the population better as compared to PII. A considerable amount of variations also exist in their asymmetries and interdigital diversities and these suggest the possibility of their genetic controls. Such genetic controls might mediate both asymmetry and interdigital diversity jointly, as there seems to be positive correlation between these measures with respect to all the three finger-dermatoglyphic traits.     

精神分裂症患者皮纹a-b嵴线数波动性不对称的研究

本文分析了精神分裂症患者134例(男性70例,女性64例)和正常对照人群331例(男性170例,女性161例)皮纹a-b嵴线数波动性不对称的分布特征。结果表明:⑴精神分裂症患者双手皮纹a-b嵴线数明显低于正常对照组(P<0.01),表现出明显增高。     

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.     

Quantitative digital dermatoglyphics in males and females of four Sardinian linguistic groups

Radial and ulnar ridge counts on each of the 10 fingers, total finger ridge count, bilateral summed radial and ulnar finger ridge counts, an index of asymmetry between homologous fingers and two indices of intraindividual diversity of finger ridge counts were used to identify biological relationships among Sardinian linguistic groups. Stepwise discriminant analysis of 26 digital traits of 1258 Sardinians, 647 females and 611 males, was carried out. The results indicate high intergroup heterogeneity; moreover, with p≤0.01 as F-to-enter and p≤0.05 as F-to-remove, only 5 of the 26 digital variables are in the model (URC R5, RRC L5, RRC R5, URC R4, URC L5). The pattern of interpopulation biological relationships shows a clearly distinct position of the Gallurian group (both males and females), which speaks an Italian dialect. It originated mainly from Corsican immigration to the Gallura region starting from the XVII century. While the properly Sardinian linguistic groups (Campidanian and Logudorian) and the Sassarian group, which speaks an Italian dialect that developed as a “lingua franca” during the Middle Ages (XII–XIV centuries) due to linguistic contact between Sardinians and Italians, are positioned close to one another. This pattern agrees more with the ethno-historical back-ground than with the linguistic one.     

Digital dermatoglyphics of 107 Bengalis.

I analyzed the finger prints of 59 male and 48 female unrelated Bengalis in a rehabilitation camp of Dacca, Bangladesh. The most common pattern type in the Bengalis was the ulnar loop (53%), then whorls (40%); arches (5%) and radial loops (2%) were the least common. Radial loops occurred most frequently on the index fingers. I have shown the arch/whorl, whorl/loop, and pattern intensity indices, and I have presented ridge counts by individual digits and by total digital ridge count. Digital dermatoglyphics in the male Bangladeshis were similar to previous findings in male Brahmins of Bengal. However, there were more whorls and arches, fewer loops, and a higher mean total digital ridge count in the female Bangladeshis than in female Brahmins.     

Sexual dimorphism in the Chuvashian population of Russia in two types of dermatoglyphic traits: principal component analysis

With the aim of determining sexual dimorphism in the component structures among the Chuvashian population of Russia, finger and palmar dermatoglyphics of 547 individuals (293 males, 254 females) were analyzed. The sex differences in two categories of dermatoglyphic traits (22 quantitative traits and 38 asymmetry and diversity traits) are reflected differently and contradictory with other ethnic groups. However, a common feature of the factor 1 "digital pattern size factor" (finger ridge counts from the first category of traits) indicate its degree of universality when compared with other populations, which suggests that the variability of finger ridge counts is determined by the same genes that control the pattern types. The factors "intra-individual finger diversity factor", and "bi-lateral asymmetry factor" extracted from the second category of dermatoglyphic traits are also similar in both sexes. However, these components are hardly described in the literature. The nature of variation of these components (from two categories of dermatoglyphic traits) appears with a good similarity between sexes, which suggests their common biological validity of the underlying component structures of the finger and palmar dermatoglyphic characters.     

Quantitative dermatoglyphic asymmetry: a comparative study between schizophrenic patients and control groups of West Bengal, India

Quantitative Fluctuating (FA) and Directional asymmetry (DA) of dermatoglyphics on digito-palmar complex were analyzed in a group of 111 patients (males: 61, females: 50) with schizophrenia (SZ), and compared to an ethnically matched phenotypically healthy control (males: 60, females: 60) through MANOVA, ANOVA and canonical Discriminant analyses. With few exceptions, asymmetries are higher among patients, and this is more prominent in FA than DA. Statistically significant differences were observed between patient and control groups, especially in males. In both sexes, FA of combined dermatoglyphic traits (e.g. total finger ridge count, total palmar pattern ridge count) are found to be a strong discriminator between the two groups with a correct classification of over 83% probability.     

Finger dermatoglyphics of the Rarhi Brahmins of Bengal

The finger prints of 138 individuals belonging to the sub-caste Rarhi Brahmin have been analyzed. In males whorls are more frequent in the right hand than the left, while it is just the reverse in case of loops and arches. Females, however, show higher frequency of loops and lesser frequency of whorls in the right hand than the left, while the arches are more frequent on the left hand of females than the right. Arches are found to be more frequent on the thumb in males, while among females it is found mostly in the second finger. The bimanual difference is statistically significant in both sexes. Right hands are found to be more monomorphic than left hands. Monomorphic hands are less frequent among females than males. In the digitwise occurrence of symmetrical combinations of different patterns, the trend is III>IV>V>I>II in males, and V>IV>III>I>II in females. Males show higher ridge counts in all fingers than do females. Ridge counts are usually found to be higher in the right hand than the left. The sex difference for mean total ridge counts is significant (t = 1.99, 0.05>P > 0.02, d.f. = 136). The bimanual difference is statistically significant for thumbs in both sexes, while the difference for the other digits is not significant.     

Quantitative dermatoglyphic markers in fra-X-syndrome

Quantitative dermatoglyphic characters of fingers and palms of 61 male patients with fra-X-syndrome and 20 female heterozygote carriers were analysed and compared with the data from 84 male and 90 female normal individuals. Univariate and multivariate analysis of the data led to the following conclusions: 1. The fra-X-syndrome patients show higher ridge count and higher MLI value (increased transversality of the main lines), and lower a-b ridge counts than the controls. In addition to this, differences are observed also for the diversity and asymmetry measures. 2. Discriminant analysis as applied to the sexes separately, showed that 75% of males can be correctly classified in their group. However, the percent of correctly classified females is lower than the males; it is 70% (fra-X female) ad 64.4% (control female). 3. D2-matrix and the comparison of TFR C values support the hypothesis of X-chromosomal doses effect on the dermatoglyphics.     

Asymmetry of the a-b ridge count in low-back pain sufferers

Fluctuating asymmetry of paired morphological structures is regarded as a measure of developmental stability. To test whether poorly canalized individuals are highly sensitive to postnatal environmental influence, we accepted the exogenous disease low-back pain as an example of such sensitivity. Asymmetry of the palmar a-b ridge count was examined in 217 males suffering from low-back pain against 300 healthy controls. Low-back pain patients showed significantly higher values of asymmetry indices indicating lower developmental stability. The results suggest that dermatoglyphic asymmetry can mark phenotypes weakly adapted to postnatal stress.     

Connections between finger print patterns and the form of terminal phalanges

The present paper resumes the theme taken up by Bonnevie in her studies of the embryonic development of dermatoglyphic systems. Relicts of the embryonic finger balls remain in later life (Fleischhacker) and influence the symmetry relationships of the terminal phalanges. Attention was, therefore, focussed on the connection between the asymmetry of terminal phalanges and that of the patterns. All loops and whorls with a different ridge count on the radial and on the ulnar side are asymmetrical. In order to determine the asymmetry of the terminal phalanges, casts were made of the fingers of 200 schoolchildren. Then, contour drawings were laid into various planes using the phalangograph (constructed on the same lines as the perigraph), and the plane of intersection of the two sides of the symmetry axis was determined planimetrically. A high correlation of r = 0·954 was established between the degree of asymmetry of the patterns and that of the terminal phalanges (cf. Figure 3).     

Condition-dependent asymmetry is fluctuating asymmetry

Asymmetry has been demonstrated to play a role in signalling systems such as sexual selection and pollination, with receivers showing a preference for symmetrical signals. Large signals often have the smallest degree of asymmetry, a finding that is consistent with signal asymmetry being condition-dependent. The kind of asymmetry displayed by signals was supposed or shown to be fluctuating asymmetry, and signals revealing individual differences in the ability to stabilize developmental processes, despite a hostile developmental environment, was supposed to be the basis for the preference for symmetric signals. Recently, it has been suggested that condition-dependent signals display antisymmetry rather than fluctuating asymmetry, based on analyses of the relationship between asymmetry and mean length of the left and the right character in a few published graphs of absolute asymmetry of signals. Here I demonstrate on the basis of a much larger number of data sets, including those previously published, that the previous results are biased because of the methods used for the analyses, and that characters with condition-dependent asymmetry show fluctuating asymmetry rather than antisymmetry. In particular, frequency distributions of signed left-minus-right character values display leptokurtosis, as predicted if asymmetry distributions reflected individual differences in developmental precision, rather than platykurtosis. Platykurtosis is predicted if the traits are antisymmetric. The preponderance of leptokurtic distributions is consistent with recent modelling showing that inherent differences in the ability of individuals to control developmental processes invariably leads to leptokurtic distributions of signed left-minus-right character values.     

Finger patterns characteristics as determinants of total ridge count variability

The total ridge count (TRC) was viewed as a common composite trait with definite correlations between its components — the ridge counts (RC) of individual fingers. The TRC variability was accordingly examined as a function of the variability of these components. The distribution of pattern types on the fingers, the RC of patterns per total as well as per finger location, and the mean finger RC were all analyzed in relation to the RC variability and to a newly described phenomenon — the mutual influence on the RC variability of different patterns present concomitantly in an individual. It was concluded that the TRC variability is conditioned by the frequencies of the same genes which are responsible for the presence of the different finger pattern types. A high negative correlation coefficient, −0.901, was found between the pattern intensity index (PII) and the coefficient of variation of the TRC. The linear regression equation was: CV=90.75−4.20 PII. Biological isolation and the ensuing consanguinity may affect the TRC variability of a population by modifying the frequencies of these genes. This influence may be a decreasing as well as an increasing one. In contrast, when a common metric trait which is determined by additive genes without any dominance (as the TRC is frequently believed to be) is subjects to consanguinization effects, only a decrease in the variation is expected. The dermatoglyphics of 625 Jewish males were investigated and the general character of some dermatoglyphic regularities and trends was compared with and corroborated by data from the literature.     

a-b palmar interdigital ridge-count in the Basque population

The a-b palmar interdigital ridge count was analyzed in a sample of 841 males and 911 females of Basque origin. Bimanual differences were not found, against that a significant sexual dimorphism. The mean ridge count value is in the lower lange of the variability among White populations.     

A family study of dermatoglyphic traits in India. Resolution of genetic and environmental effects for manus,pes and total pattern ridge counts in man

Various constructed ridge count phenotypes were studied in two endogamous populations from peninsular India. Heritabilities were estimated for five summed pattern ridge count traits: fingers and toes together; palms and soles together; fingers and palms together (manus); toes and soles together (pes); and fingers, palms, toes and soles together, defined as the total ridge count in man. In general, these phenotypes were found to he highly heritable, with the summed ridge counts for fingers and toes, and total ridge count showing almost Complete determination by additive polygenes. Total manus and pes pattern counts are less heritable. Little or no uterine environmental effects were detected for any of these phenotypes.