Dermatoglyphics is the study of dermal ridges. Since dermatoglyphic characters are recognized as a unique individual trait and follow a multifactorial or polygenic pattern of inheritance, it is necessary to understand the variations leading to this pattern. The present paper, through appropriate descriptive approach, has revealed the variation in the pattern of inheritance in the TFRCs of the Dumagat-Remontados from Puray, Rodriguez, Rizal, Philippines. The study also reported a large discrepancy on the total fingerprint ridge count among the Dumagat-Remontados compared to established researches. Also, the increased heterozygosity due to genetic admixture led to the dominant occurrence of the loop pattern (ulnar) in the fingerprints of this group of indigenous people as compared to few established data stating that the frequency of whorl patterns dominates the universal population and other Asian racial groups. In this study, a special feature on the fingerprint patterns of the pure Dumagat-Remontados was reported. Aside from the high frequency of loops and whorls, a distinct club dent, concluded to be a unique feature found among this tribal population, was noted from at least one of the fingers of the majority of the pure sample.
Dermatoglyphics is a field that has attracted a great number of scientists from across genetics, medicine, and anthropology to explore links on genetically determined diseases. Moreover, for many years, fingerprints were used as a means of identification and authentication based on their individual peculiarities and uniqueness. According to Ismail et al. [
Dermatoglyphic study is comprised of two main aspects: patterns and total fingerprint ridge counts (TFRCs). Patterns are primarily due to the convoluted layers of cells of the epidermis wherein the peaks of the ridges are the locations of the pores of the sweat glands. Figure
Structure of a fingerprint.
Fogle [
Human fingerprint is characterized by various types of ridge patterns classified as an arch, a loop, or a whorl—each has a unique characteristic with respect to a reference point called a triradius. The arch is the least frequent pattern and is subdivided into either plain or tented arch consisting of at least one upthrusting ridge, which tends to bisect superior ridges at right angles. The loop pattern is more complicated classified as either ulnar (with a triradius that is on the side of the thumb, with the loop opening towards the pinky finger) or radial (with a triradius that is on the side of the pinky finger, with the loop opening towards the thumb). The whorl has two triradii and has four types: plain whorl, central pocket whorl, double-loop whorl, and the superwhorl. According to Holt [
Ridge count is related to two different timed events: the timing of the onset of volar pad regression versus the timing of the onset of primary ridge formation [
Dermatoglyphics, as termed by Cummins [
The Dumagat-Remontados, identified as a Negrito ethnolinguistic group, derive their name from the Spanish verb “remontar,” meaning, “to flee to the hills,” “to frighten away,” or “go back to the mountains.” These indigenous peoples (IPs) are said to be the descendants of lowlanders who opted to live in the mountains to avoid subjugation by the Spaniards. Subsequently, they intermarried with the Negrito groups. The Remontados are also referred to as Dumagat-Remontados and they prefer to be called “taga-bundok” (from the mountains) or “magkakaingin” (those who practice kaingin).
The Remontados are mixed-blooded (genetic admixture) group of people; hence, they have a combination of a Negrito and a lowland Filipino features with deep brown skin, average height of 128 centimeters, curly-to-straight hair, high cheekbones, small slightly flared noses, Mongol-type eyes, and teeth that are sometimes filed and red from chewing betel nut. They also have lean and small built but with strong firm muscles and well-developed extremities including broad feet, because of physical daily work in the field such as climbing hills and hiking in the forests. In the Philippines, although the Dumagat-Remontados are seminomadic, there is no reported case of heavy out-migration. They roam in a specific geographic range which they consider their home base.
In 1936, the total population of Remontados in the Province of Eastern Rizal, Philippines, was around 2,650. After 45 years, this was recorded to around 2,750. The group’s population growth is almost stationary as compared to the province’s non-Remontado populace that has increased five times in the same time period.
In most dermatoglyphic studies conducted, fingerprint ridge counts were given emphasis highly by many researchers in terms of their quantitative aspect. In the study conducted by Holt [
Fingerprint inheritance was also investigated in terms of the general distribution of the patterns in relation to the different blood groups [
Another study reported that the gross distortions in the patterns can occur in association with any limb malformation of early prenatal onset [
In most of the previous studies, there was really an emphasis on fingerprints because of their uniqueness to every individual. In this paper, an investigation of the pattern of fingerprints in Dumagat-Remontados was done which aims to investigate whether the TFRCs of this Philippine tribal population follow the polygenic pattern of inheritance. Comparisons of the TFRCs within gender (males and females), genotypic lineage (pure and hybrid), and the frequencies of occurrences of the common fingerprint pattern types were also examined.
Dumagat-Remontados from Puray, Rodriguez, Province of Rizal, Philippines, were chosen purposively as respondents of this study. The total fingerprint ridge counts (TFRCs) and the fingerprint patterns of fifty (50) Dumagat-Remontados were recorded by manual counting and identification using a magnifying lens. TFRC was obtained by summing the ridge counts from all fingers of both hands. Primary patterns were observed and TFRCs were counted as follows: ridge count in an arch is counted as zero, in a loop, the number of ridges between the center and the triradius was counted, in a whorl, the numbers of both the radial and ulnar triradius were counted and the greater of the two was used. Prior to ridge counting and pattern identification, the respondents were interviewed of their genotypic lineages (e.g., pure genotypic lineages are those whose parents are both Dumagat-Remontados and hybrid genotypic lineages are those with either a Dumagat-Remontado father or mother).
All data were tabulated and statistically treated. Descriptive statistics were used to establish significant frequencies in the sample. Chi-square test of significance was also computed to determine whether there are significant differences in the occurrences of patterns in every individual. Comparison of the mean TFRCs for gender and between pure and hybrid individuals in the sample were obtained separately. Hybrid individuals in the sample, however, were limited up to the first filial generation. It is important to note here that the genetic admixture of the tribal population was due to the intermarriage of the tribal members with lowland Filipinos. It can also be inferred that the stability of the population number of this tribal group was due to the hybridization (intermarriage) of the pure Dumagat-Remontado with individuals outside their tribe.
Results revealed that in this indigenous group of people, the attempt to uncover the mode of inheritance of dermatoglyphic traits is conclusive and that it fits the multifactorial model or polygenic pattern of inheritance. Total fingerprint ridge counts range from 91 to 279 with a mean of 203.12, standard deviation of 37.57 with a slight negatively-skewed distribution value of −0.877 (Figure
Total fingerprint ridge count distribution among Dumagat-Remontados.
Table
Descriptive statistics of the TFRC of males and females.
Descriptive Statistics | Fingerprints | |
---|---|---|
Male ( |
Female ( |
|
Mean | 217.5 | 195.03 |
Std. deviation | 33.79 | 37.66 |
Range | 127 | 157 |
Minimum | 152 | 91 |
Maximum | 279 | 248 |
Holt [
A typical volar pad of a Dumagat-Remontado.
Table
Frequencies of each fingerprint pattern type.
Pattern types | Frequency | Percentage |
---|---|---|
Whorl | 212 | 42.4 |
Ulnar loop | 271 | 54.2 |
Radial loop | 6 | 1.2 |
Arch | 11 | 2.2 |
| ||
Total | 500 | 100.0 |
Frequency distribution of the different fingerprint pattern types.
The difference in the frequencies of occurrences of the fingerprint patterns within gender (male and female) and genotypic lineage (pure and hybrid) was also tested using the chi-square test of significance and results show stable significant differences
Chi-square values for frequency distributions of the different fingerprint pattern types in selected relationships.
Relationships | Finger prints |
|
---|---|---|
Male-female | 16.909 | 0.001 |
Pure-hybrid | 18.39 | 0.000 |
Critical value at
In this study, a special feature on the fingerprint patterns of the pure Dumagat-Remontados was observed. Moreover, the high frequencies of loop occurrence might have been due to the genetic admixture that happened in the current population. Dermatoglyphic traits are steadily inherited and show slow changes within a population, but because of genetic admixture, the variability might be highly evident [
Observed unique feature from the fingerprints of the Dumagat-Remontado.