Genetic analysis of dermatoglyphic patterns in twins.

Analysis of variance was performed on 71 dermatoglyphic variables in 424 twin sets. Using a method of twin analysis estimates of genetic variance were obtained. 54 of the variables were quantitated using a scoring system with modifications of arch or no pattern = 0, loops = 1, whorl = 2. The results indicated a significant genetic influence in most pattern areas. Patterning was more genetically controlled in the hand than in the foot. The hallucal area had the most significant genetic component of the foot while the patterns in the thumb had nonsignificant components of genetic variance. The thumb deviated from patterning in the rest of the fingers and may be more closely related to big-toe patterning.     

Comparisons of dermatoglyphic patterns in monochorionic and dichorionic monozygotic twins

The data presented here indicate that different influences affect dermatoglyphic pattern development in MC-MZ and DC-MZ twins. Only five of 84 variables had significant mean differences but their clustering suggested a real difference in mean placement of the atd angle. Nineteen of 84 variables had significantly different within-pair mean squares for the two twin types. Larger numbers of twins will be required to obtain accurate estimates of the magnitude of the dermatoglyphic differences between MC-MZ and DC-MZ twins. Studies of dermatoglyphics in MC-MZ and DC-MZ twins are important to the understanding of factors which influence early embryonic development and when better documented may provide a mechanism for retrospectively diagnosing placental type of MZ twins.     

Prenatal selection and dermatoglyphic patterns

Although human dermatoglyphics have been extensively studied, little is known of the prenatal origins of dermatoglyphic patterns. Digital patterns, i.e., loops, whorls, and arches, were obtained from 81 human abortuses, ranging in age from 11 to 25 weeks post-fertilization. Patterns were discernible with the earliest indications of epidermal ridge development. Findings indicate that pattern frequencies during early prenatal development differ from those of later fetal and postnatal periods. Furthermore, a high frequency of arches is seen associated with spontaneous abortion, suggesting evidence for prenatal selection in human abortuses.     

Genetic analysis of bilateral dermatoglyphic asymmetry in twins and their parents

The data for this study were collected on 64 twin pairs (30 MZ and 34 DZ) and their 128 parents. Two following hypotheses were evaluated: 1. Bilateral asymmetry is significantly genetically controlled; 2. The twinning phenomenon would affect the magnitude of bilateral asymmetry. The results revealed no statistically significant differences between mean values of MZ and DZ twins and their parents for the majority of the traits. Significant differences were recorded for only 6 of 96 comparisons (6%). Analysis of variance revealed separated sources of MZ, DZ and singleton variance. F-ratios, contrasting variances between different groups were significant for 26 of 96 comparisons (27%) showing heterogeneity of variance between zygosities and between twins and their parents. In addition, environmental covariance appeared to be larger for MZ than DZ with respect to directional asymmetry (DA) for all 16 traits and fluctuating asymmetry (FA) for 14 traits. These observations showed complex environmental determinism for bilateral asymmetry for the majority of dermatoglyphic traits. Significant genetic variance ratios (GVRs) were observed for four variables (25%) with respect to DA and three variables (18.75%) with respect to FA. All these significant GVRs were rendered insignificant because of evidence of greater environmental covariance for MZ twins, except possibly for DA for URC4.     

Inbreeding effects on bilateral asymmetry of dermatoglyphic patterns

Bilateral correlations are higher and bilateral variances within individuals smaller in the samples of inbred individuals than in matched control groups of the same sex for pattern intensities on fingers in four series of data and also for pattern intensities on palms, toes, and soles and the palmer main line indices in the data collected from a Muslin population of West Bengal. This trend is not apparent in two series of data from the Yanadi tribe, in which the inbred and noninbred samples are not controlled for random variation of genes and environment. Increased variances between individuals and changes in means and distributions of the traits in the inbred samples of the matched data indicate some influence of homozygosity of genes for the traits on their asymmetry. The reduced variability of asymmetry of the traits in the inbred cannot be explained by homozygosity of genes for either directional or absolute asymmetry. One possible explanation is that heterozygotes for these dermatoglyphic triats are more responsive to environmental stress than homozygotes and/or increased selection in the homozygotes against genetic disorders associated with dermatoglyphic asymmetry may reduce the variability of such asymmetry.     

Inheritance of dermatoglyphic traits in twins: univariate and bivariate variance decomposition analysis

Dermatoglyphic traits in a sample of twins were analyzed to estimate the resemblance between MZ and DZ twins and to evaluate the mode of inheritance by using the maximum likelihood-based Variance decomposition analysis. The additive genetic variance component was significant in both sexes for four traits--PII, AB_RC, RC_HB, and ATD_L. AB RC and RC_HB had significant sex differences in means, whereas PII and ATD_L did not. The results of the Bivariate Variance decomposition analysis revealed that PII and RC_HB have a significant correlation in both genetic and residual components. Significant correlation in the additive genetic variance between AB_RC and ATD_L was observed. The same analysis only for the females sub-sample in the three traits RBL, RBR and AB_DIS shows that the additive genetic RBR component was significant and the AB_DIS sibling component was not significant while others cannot be constrained to zero. The additive variance for AB DIS sibling component was not significant. The three components additive, sibling and residual were significantly correlated between each pair of traits revealed by the Bivariate Variance decomposition analysis.     

Digital dermatoglyphic patterns in a sample of the Nigerian population

Eight hundred Nigerians (400 males and 400 females) were screened for the analysis of digital dermatoglyphic patterns. The frequency distribution of the patterns are 52.09%, 27.67%, 19.20% and 1.13% for ulnar loops, whorls, arches and radial loops respectively. Except for arches, the males have more of the patterns than females. The pattern intensity indices for males and females are 11.2 and 9.9 respectively. Bilateral symmetry is similar in both sexes and the percent distribution is as high as 81.5% and 84% on digit V in males and females respectively.     

Inheritance of 18 quantitative dermatoglyphic traits based on factors in MZ and DZ twins

18 quantitative finger and palmar dermatoglyphic traits were analyzed with the aim of determining genetic effects and common familial environmental influences on a large (358 nuclear pedigrees) number of twins (MZ and DZ). Genetic analysis based on principal factors includes variance and bivariate variance decomposition analysis. Especially, Factor 1 (digital pattern size) is remarkable, due to its degree of universality. The results of genetic analysis revealed all three extracted factors have significant proportion of additive genetic variance (93.5% to 72.9%). The main results of bivariate variance decomposition analysis appears significant correlation in residual variance between digital pattern size factor (Factor 1) versus finger pattern intensity factor (Factor 4), and palmar main lines factor (Factor 2) verses a-b ridge count (Factor 3), but there was no significant correlation in the genetic variance of factors.     

Parent-offspring resemblance of palmar and plantar dermatoglyphic patterns in Down syndrome

With the aim of investigating the influence of trisomy 21 on the expression of heritable morphological features, we recorded the palmar and plantar dermatoglyphic patterns in 48 children with Down syndrome (DS), in both their parents, and, as a control, in 57 of their siblings. Using the Kendall tau rank correlation test, a considerable parental influence on the frequency of true patterns in the interdigital areas (IDA) III and IV of the palms (P = 0.3%) and soles (P = 1.0% and 3.8%, respectively) is demonstrated for the control siblings. In the children with DS, this influence is discernible as well, although with no statistical significance. A greater number of families may be required to settle the question.     

An aid for identification of dermatoglyphic patterns in subjects difficult to fingerprint

The author's in vivo microscopic technique, initially developed for observation of capillaries in human skin, can be helpful for detecting fingerprint patterns in subjects in whom an abnormal skin surface makes it difficult to record or even observe these patterns by the usual techniques.     

Digital and palmar dermatoglyphic patterns among natives of extreme northwest Nepal

A dermatoglyphic study was made of two high-altitude populations inhabiting the same ecozone in extreme northwest Nepal. Despite cultural and linguistic differences there appears to be a significant amount of dermatoglyphic homology between the Buddhist-Tibetan villages and their Hindu-Caucasian neighbors.     

Digital dermatoglyphic patterns of Eskimo and Amerindian populations: relationships between geographic, dermatoglyphic, genetic, and linguistic distances.

Dermatoglyphic traits have been used to assess population affinities and structure. Here, we describe the digital patterns of four Eskimo populations from Alaska: two Yupik-speaking villages from St. Lawrence Island and two Inupik groups presently residing on mainland Alaska. For a broader evolutionary perspective, these four Eskimo populations are compared to other Inuit groups, to North American Indian populations, and to Siberian aggregates. The genetic structures of 18 New and Old World populations were explored using R-matrix plots and Wright's FST values. The relationships between dermatoglyphic, blood genetic, geographic, and linguistic distances were assessed by comparing matrices through Mantel correlations and through partial and multiple correlations. Statistically significant relationships between dermatoglyphics and genetics, genetics and geography, and geography and language were revealed. In addition, significant correlations between dermatoglyphics and geography, with linguistic variation constant, were noted for females but not for males. These results attest to the usefulness of dermatoglyphics in resolving various evolutionary questions concerning normal human variation.     

Studies of endemic cretinism in Papua New Guinea: digital and palmar dermatoglyphic patterns

We have tested the hypothesis that the abnormal development of the central nervous system seen in endemic cretinism might be accompanied by concurrent abnormal dermatoglyphic patterns. We compared digital and palmar dermatoglyphics of normal individuals and endemic cretins inhabiting the Huon Peninsula of Papua New Guinea. The population sampled from the Irumu River Valley included 118 males and 114 females with 22 male cretins and 23 female cretins. The population sampled from the Wantoat River Valley included 72 males and 38 females with 12 male cretins. No pathognomonic patterns were found that could identify the endemic cretin subpopulation. However, the occurrence of a number of differences between controls and cretins suggests that subtle changes in dermatoglyphic patterns accompany the anomalous development of the CNS secondary to maternal iodine deficiency. We discuss the significance of these findings and compare the dermatoglyphic patterns of normal Irumu and Wantoat natives and 21 other populations of Papua New Guinea.     

Use of the integral parameter of dermatoglyphic differences for determining the type of zygosity of twins]

A method is described increasing the reliability of twin zygosity diagnosis in cases when the possibility of using a large number of mendelian markers is restricted. The method is based on the determination of generalized index of dermatoglyphic differences between members of twin pair for 18 characteris of finger and palm dermatoglyphics and on principles of multivariate genetic analysis, which is worked out to determine the degree of heritability of multifactorial character and to study the structure of hereditary predisposition to multifactorial diseases. The efficiency of the method with respect to determinating the type of twin zygosity is approximately equivalent to the efficiency of using 5--6 mendelian marker systems.     

Trends in dermatoglyphic research

A brief update of recent developments and trends in dermatoglyphic research is presented, based on a 1980–87 literature review. The discussed topics include anthropological, genetic, medical and developmental studies of the epidermal ridge patterns and flexion creases, including dermatoglyphic variability, new methodological and classification approaches, studies of nonhuman primates and of other experimental animals. Rather than an exhaustive survey of the existing literature, the purpose of this communication is to point out specific accomplishments, novel approaches, and emerging trends in various fields of dermatoglyphic research.