Commitment to X inactivation precedes the twinning event in monochorionic MZ twins.

To gain insight into the timing of twinning, we have examined a closely related event, X-chromosome inactivation, in female MZ twin pairs. X-inactivation patterns in peripheral blood and buccal mucosa were compared between monochorionic MZ (MC-MZ) and dichorionic MZ (DC-MZ) twins. Overall, the MC-MZ twins displayed highly similar X-inactivation patterns, whereas DC-MZ twins frequently differed in their X-inactivation patterns, when both tissues were tested. Previous experimental data suggest that commitment to X inactivation occurs when there are 10-20 cells in the embryo. Simulation of embryo splitting after commitment to X inactivation suggests that MC-MZ twinning occurs three or four rounds of replication after X inactivation, whereas a DC-MZ twinning event occurs earlier, before or around the time of X inactivation. Finally, the overall degree of skewing in the MZ twins was not significantly different from that observed in singletons. This indicates that X inactivation does not play a direct role in the twinning process, and it further suggests that extreme unequal splitting is not a common mechanism of twin formation.     

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.     

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.     

Population affinities assessed by dermatoglyphic and hemogenetic variables

13 dermatoglyphic variables have been studied in eight population samples (five smaller isolated and three larger populations) to identify the possible differences between the larger and the smaller isolated populations. The data and neighbor joining trees for the dermatoglyphic variables show distinct differences between males and females. The isolated population of the Lutheran Mountains is clearly separated from the other populations. Combining the results of dermatoglyphic and 12 hemogenetic variables (only for six populations) the male and female trees are nearly identical. The three isolated populations are clearly separated, whereas the larger ones show smaller distances.     

Multivariate analysis of sexual dimorphism in two types of dermatoglyphic traits in five endogamous populations of West Bengal, India

Five different endogamous populations who encompass the main social rank in the caste hierarchy of West Bengal were analysed for this report. The present approach is to compare the pattern of sex differences/similarities exhibited by two different sets of dermatoglyphic traits. Cluster and discriminant analysis and Mantel test of matrix correlations were performed. The nature of variation between sexes within population groups and two types of variable sets has a good similarity in all five populations. These results strongly suggest that the two categories of dermatoglyphic variables provide similar possibilities to discriminate between the sexes in populations.     

云南省少数民族皮纹研究—白族等十一个民族皮纹正常值测定

本文报告了云南省白族等11个少数民族14项皮纹正常值参数,并与汉族、北美白人作了比较,进行了统计学分析与聚类分析。结果表明,皮纹这一类遗传性状不仅在各人种之间有显著差异,而且在我国各民族之间也存在显著差异。各民族有自己皮纹的特异性。     

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.     

海峡两岸汉民族与南岛民族肤纹之比较

本文研究与整理海峡两岸汉民族与南岛民族的肤纹数据,来比较与探讨目前他们的肤纹形态上的异同。研究群体包含台湾的汉人与原住民族群,以及大陆的汉族与海南的回辉人。研究结果显示两岸非官话(亦作北方方言)区汉族虽然在肤纹参数上有些许不同,但皆属于北方群。而南岛民族的回辉人和台湾原住民则分属南方和北方群,并且在肤纹参数上有非常显著的不同。这是第一个两岸南岛民族的肤纹比较研究,也是第一个非官话区汉人群体的肤纹比较研究。     

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.     

A dermatoglyphic study of the Kavalan aboriginal population of Taiwan

By the 1970s, a number of dermatoglyphic studies of Taiwan aborigines (Gaoshan nationality) had been published, however in each only a few dermatoglyphic variables were addressed. Since that time, little new research has been conducted. In this study, we collected and analyzed the dermatoglyphs of 100 individuals of Kavalan, a Taiwan aboriginal population, and we reported a wide range of dermatoglyphic variables including total finger ridge count (TFRC), a-b total ridge count (a-b RC), atd angle and axial triradius percent distance (tPD), and frequencies of fingerprint pattern, palmar thenar pattern, palmar interdigital pattern, palmar hypothenar pattern, and simian line. This study is the first comprehensive dermatoglyphic research of any Taiwan aboriginal population.     

A dermatoglyphic study of the Kavalan aboriginal population of Taiwan

By the 1970s, a number of dermatoglyphic studies of Taiwan aborigines (Gaoshan nationality) had been published, however in each only a few dermatoglyphic variables were addressed. Since that time, little new research has been conducted. In this study, we collected and analyzed the dermatoglyphs of 100 individuals of Kavalan, a Taiwan aboriginal population, and we reported a wide range of dermatoglyphic variables including total finger ridge count (TFRC), a-b total ridge count (a-b RC), atd angle and axial triradius percent distance (tPD), and frequencies of fingerprint pattern, palmar thenar pattern, palmar interdigital pattern, palmar hypothenar pattern, and simian line. This study is the first comprehensive dermatoglyphic research of any Taiwan aboriginal population.     

Effect of prenatal testosterone administration on palmar dermatoglyphic intercore ridge counts of rhesus monkeys (Macaca mulatta)

Dermatoglyphic ridge counts of the prints of 59 rhesus monkeys (Macaca mulatta) whose mothers had been treated with injections of testosterone during their pregnancies were studied to determine the effect of the day the hormone began to be administered, the amount of hormone administered, and the number of days of hormone administration upon the dermatoglyphic variation of the offspring. Of the three hormone variables, only the day of beginning administration (STARTDAY) was significantly associated with dermatoglyphic variation, and its positive significance was demonstrated with the ridge counts of Area I on both the left and right hand, Area II of the left hand, and the total ridge counts of both hands. These results are discussed within the context of the timing of the dermatoglyphic window, and the differences in the findings between the monkey and earlier human studies are addressed. © 1994 Wiley-Liss, Inc.     

Dermatoglyphic asymmetry and testosterone levels in normal males

Dermatoglyphic prints and salivary samples were taken on a sample of 39 adult males. A statistical relationship between dermatoglyphic asymmetry and adult testosterone levels as measured in saliva was examined for seven dermatoglyphic variables by means of correlation, regression, and analysis of covariance, controlling for age and stature when necessary. The first two types of analyses indicated a significant effect of testosterone level upon the asymmetry of three dermatoglyphic variables: a-b ridge count, palmar pattern intensity, and the combined pattern intensity of palm and digits. Analysis of covariance, which examined the effect of testosterone level as a categorical variable, while holding age or stature constant, demonstrated the asymmetry of five variables to be significantly affected by testosterone level: radial digital count, digital pattern intensity, palmar pattern intensity, total digital ridge count, and the combined palmar and digital intensity. Although there is as yet only associational evidence linking levels of prenatal and secondary testosterone, the results of the present study lend support to the hypothesis that prenatal testosterone levels may have a significant effect on the development of dermatoglyphics. © 1993 Wiley-Liss, Inc.     

Genetic and environmental influence on the asymmetry of dermatoglyphic traits

Fluctuating asymmetry (FA) is defined as random deviations from bilateral symmetry of the body. Thus, its magnitude is often used to evaluate developmental homeostasis. In this study we evaluate the following hypotheses: 1) FA of dermatoglyphic traits has a significant genetic component; 2) prenatal maternal environment (PME) has a significant effect on the FA of dermatoglyphic traits in developmentally healthy individuals; and 3) genetic or environmental factors affect FA on organismal or systemic levels. Therefore, their effect is better seen in composite scores of FA rather than in FA indices for single traits. We analyzed 15 dermatoglyphic traits from 140 pairs of monozygous twins, 120 pairs of dizygous twins, and 106 pairs of mothers and daughters. All individuals were developmentally healthy. The influence of genetic and environmental factors on FA was evaluated by analysis of variance and regression analysis. For a majority of the traits in our study, FA showed significant but weak heritabilities, with values falling within the 0.20-0.35 range. None of the traits taken separately demonstrated the effect of PME on FA to be significantly greater than zero. The composite score of FA tended to have greater heritability values than individual traits. One of them, obtained in principal components analysis, showed a significant PME effect, supporting the hypothesis that FA is a systemic property.     

Comparative analysis of qualitative dermatoglyphic traits of Albanian and Turkish populations living in the area of Dukagjin Valley in Kosovo

Dermatoglyphic prints were collected from 800 inhabitants of Dukagjin valley in Kosovo. The sample consisted of two ethnically different sub-populations who refer themselves as Albanians (N = 400) and Turks (N = 400). Qualitative analysis of prints concerned the frequency of the patterns on fingers (arch, ulnar and radial loop, whorl, accidental whorl) and on palms (Thenar and I, II, III, and IV interdigital area and the hypothenar, main line index, and the axial "t" triradius position). As was expected due to previous study of quantitative dermatoglyphic traits, in the same population the Alba-nians and Turks showed to be significantly different in most explored qualitative dermatoglyphic variables. Found differences indicated that the reproductive isolation between the Albanian and Turkish population in Kosovo is substantial, despite the fact that those two ethnic sub-populations live in the close vicinity through several centuries.     

Differences in protocols of craniofacial development related to twinship and zygosity

Using 56 adult dental diameters as a subsystem model for craniofacial development, we show that monozygotic (MZ), dizygotic (DZ), and singleton groups differ significantly in developmental relationships assessed by multivariate statistical methods under commonly accepted assumptions. Given the differences observed, we suggest that any assumption of developmental equivalence between MZ and DZ twins, or between twins of either group and singletons, for variables of craniofacial or behavioral development, may be subject to serious doubt. Implications for twin study theory and methodology, and for study of early human development, are discussed.     

Dermatoglyphic study among sex and other crime convicts

An attempt was made to investigate dermatoglyphic variation between four sex-crimes (SC) and four sex and other crime (SOC) convicts. These were compared with 10 endogamous and 11 penal populations. The results indicate that the two closely related sex crime cases IPC-363 and IPC 366 («kidnap» and «abducting») show wide differences in dermatoglyphic characters. A comparison of sex crimes with sex and other crime cases showed least differences in the case of IPC-363, IPC-363 KC and in IPC 366 and IPC-366 AC but wide differences in IPC-354 («molestation») cases. The dendrograms suggest that the eight sex crime cases cluster together and are different from other endogamous and penal populations. The significant low mean finger ridge count observed in the case of IPC-366 is in agreement with other studies, suggesting a strong association between crime (sex) and dermatoglyphics.     

Genetical distance and dermatoglyphic characters. III. Dermatoglyphic distances within twin pairs, between left and right sides and between normals and 21-trisomics

The dermatoglyphic (genetical) distance coefficients have been estimated within monozygotic and dizygotic twin pairs, between left and right sides of the same individual and between normal subjects and 21-trisomics. All the coefficients have been based, in turn, on frequencies of fingertip, palmar and sole pattern elements, separately and for all characters combined. Quantitative variables (pattern intensities) have also been used for independent evaluation of the C2H distance coefficient in monozygotic and dizygotic twins, and in 21-trisomics as compared with normal individuals. The values of a distance have then been considered in relation to the degree of genetical likeness between the compared items as well as to the relative contribution of each pattern combination to the overall value of a distance. Some limitations in the interpretation of the results, connected mainly with statistical procedures, are also discussed.