Relationship of Fingerprints with Blood Group and Sex—A Comparative Study

Abstract

Background:

Fingerprints are a unique pattern of friction ridges, which remain constant throughout one’s lifetime. Several studies have shown an association between fingerprint patterns, blood groups, and gender. This study was prompted by limited studies in this population.

Objective:

To identify the correlation between fingerprints with blood groups and sex.

Materials and Methods:

A cross-sectional study was undertaken in a specific population in India. A total of 50 samples (25 males and 25 females), aged 3 to 63 years, were recruited. Patterns of all 10 fingers were recorded, and the blood group identified as ABO and Rh system. In total, 500 fingerprint samples were analyzed against sex and blood group. The association between parameters was obtained using the Chi-square test.

Results:

Loops were the common pattern observed, followed by whorls, composites, and arches. Loop were common in males, while whorls in females, but no significant association was found between patterns and sex. Most frequently encountered pattern were whorls on ring fingers, arches on index fingers, composites on thumb, and loops on middle and little fingers, in both males and females. Loops were common amongst ABO blood groups, except in AB blood group which showed prevalence of whorls. Loops were the most prevalent pattern in both Rh +ve and Rh –ve groups. Significant association was found between fingerprints with ABO blood group (p<0.001).

Conclusions:

This study identified associations between fingerprints patterns and ABO blood groups and specific digits, but not with sex. For validation and application, further research with larger sample size is needed.

INTRODUCTION

Fingerprints are a unique and extremely individualistic pattern of friction ridges, seen along the distal area of the phalanges over the hands. The study of these patterns is referred to as dermatoglyphics. The elevated surfaces are called papillary or friction ridges, and the valleys between the two ridges are called furrows or grooves. The science that utilizes fingerprints for identification is called dactyloscopy. Fingerprint patterns are formed during the early stages of fetal development and are determined genotypically, thus remaining constant throughout the lifetime of a person.[1] The formation and development of epidermal ridges are greatly affected by dermal papillae. The proliferation of the dermis, forming papillary projections into the epidermis, leads to the development of friction ridges. These friction ridges are fully formed between 11 and 24^th week of embryonic development.[2] Monozygotic twins show close resemblance in their dermatoglyphic patterns, indicating shared genetic factors.[1] Fingerprints are unique for each individual and are never identical between two fingers. The uniqueness of fingerprints finds a powerful application in personal identification, biometric technology, and the legal system, where they play a crucial role in criminal investigations, evidence collection, and verifying identities in court proceedings.

Recent studies have explored the potential relationship between fingerprints and other physiological characteristics, such as blood group and gender. Gowda and Rao (1996), Kshirsagar et al. (2001), Bhavana D et al. (2013), Joshi S et al. (2016), and Kc S et al. (2018) have shown whorls to be the second commonest pattern after loops, across ABO groupings.[2,3,4,5,6] The least common of the types of fingerprints that were observed belonged to arches. Across multiple studies that were conducted, the overall distribution of these patterns in ABO blood groups remained more or less consistent. However, several other studies, such as those conducted by Saranya Manikandan et al. (2019), Singh B et al. (2016), Raloti SK et al. (2013), Rastogi and Pillai (2010), and Bharadwaja et al. (2004), have identified the correlation between various fingerprint patterns and blood types.[7,8,9,10,11]

Similarly, researchers have investigated whether there are any notable differences in fingerprint patterns between males and females, with some studies suggesting that certain fingerprint types may be more common in one gender than the other. Studies done by Bhavana D et al. (2013), Joshi S et al. (2016), Rastogi and Pillai (2010), and Kukadiya U et al. (2013) have shown that there was an increased proportion of loops among females and whorls among males.[2,5,10,12]

While these findings are intriguing, it is essential to note that the relationship between fingerprints, blood groups, and gender in different populations is not fully understood. Additional research is needed to explore these potential connections further and their implications for forensics and biometrics. Thus, the present study aims to analyze this association, as understanding the relationship between these parameters, which will help increase the accuracy of personal identification. It can also help develop profiles of potential suspects, narrow down suspect pools, link and prioritize evidence, and drive technological innovations. Comprehensive profiling and objective methodologies for personal identification of a person can reduce biases in forensic analysis and strengthen the legal evidence. Additionally, only limited studies in this specific population, with these objectives, were conducted, hence prompting this study.

SUBJECTS AND METHODS

The study was performed in accordance with the ethical standards as laid down in the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. After obtaining the Scientific Review Board clearance, the study using a cross-sectional design was carried out in Kannur district of Kerala, India. Fifty individuals (25 males and 25 females), aged between 3 and 63, were enrolled on the study. Written informed consent was obtained from each participant, and for minors, consent was provided by the parents, along with the child’s assent. Fingerprint patterns (rolled and plain impressions) were recorded using an ink pad on the fingerprint recording slip. Rolled impressions of each finger from both hands were taken in separate columns, with the thumb rolled toward the body and all other fingers rolled away from the body. Hence, 500 fingerprint samples were collected in total. Additional care was employed to ensure that there were no artefacts. i.e. smudging. During the sample collection phase, individuals with amputated fingers, deep burns over the fingers or skin diseases which make it challenging to record the fingerprints, were excluded from this study. The patterns were identified as loops, whorls, arches, and composites. The blood group information including ABO and Rh groups (Rh +ve or Rh -ve) of the participants was documented, and those who were unaware of their blood group were excluded from the study. The Chi-square statistical test was used to analyze the relationship between fingerprints, blood group, and sex.

RESULTS AND OBSERVATIONS

Several studies have attempted to determine the association of fingerprints with blood group and gender. Most of these studies have focused on identifying the prevalence of specific fingerprint patterns, like loops and whorls, within males and females. Drawing definitive conclusions is challenging, as the methodologies and sample sizes of these studies varied significantly. Also, the underlying mechanism that can explain the association between fingerprints, gender, and blood group remains largely unknown.

No relationship between sex and fingerprint pattern of any statistical significance could be determined based on the findings of the current study (P = 0.661). In both males and females, the most commonly encountered patterns in order were loops, whorls, composites, and arches. Despite the varying sample sizes, our findings aligned with various authors, all of whom, suggested that loops are the most common pattern encountered in the general population.[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22] However, this finding contrasted with the findings of Thakur et al. (2019),[23] which found whorl to be the most prevalent pattern. The discrepancy in our findings can be attributed to changes in demographic characteristics.

George SM et al.,[24] in their study, identified a gender-based relationship with fingerprints and concluded that the most commonly encountered pattern in males were loops, arches, and whorls and in females whorls, loops, and arch patterns in decreasing order of prevalence. In the present study, whorls were more prevalent among females, accounting for 35.6% of their total fingerprint patterns, compared to 31.2% in males [Table 1]. This observation contradicts the findings of other authors, who found that females had a greater frequency of loops while males showed an increased frequency of whorls.[5,8,9,12,21,25] In similar research, Rastogi and Pillai (2010) found that females had a greater frequency of loops and arches, while males had a greater frequency of whorls.[10] In this study, we observed that the occurrence of composite fingerprint patterns was highest on the thumb among females (22%) and on the little finger among males (14%), among all the fingerprint analyzed. Similarly, arches were mainly found on the index finger in both males (10%) and females (12%), which was aligning with the results of Arun Kumar KR et al. (2016) and Mehta and Mehta (2011).[18,26]

Table 1.

Distribution of fingerprint patterns among males and females

Digits	Sex	Distribution of fingerprint patterns among males and females								Total
		Arches	%	Whorls	%	Loops	%	Composites	%
Thumb	Male	0	0	13	26	31	62	6	12	50
	Female	1	2	11	22	27	54	11	22	50
Index	Male	5	10	19	38	21	42	5	10	50
	Female	6	12	19	38	22	44	3	6	50
Middle	Male	2	4	12	24	35	70	1	2	50
	Female	2	4	12	24	35	70	1	2	50
Ring	Male	2	4	27	54	20	40	1	2	50
	Female	0	0	29	58	16	32	5	10	50
Little	Male	0	0	7	14	36	72	7	14	50
	Female	1	2	18	36	29	58	2	4	50
Total	Male	9	3.6	78	31.2	143	57.2	20	8	250
	Female	10	0.04	89	35.6	129	51.6	22	8.8	250

χ²=1.59, df=3, P=0.661

Whorls were the most frequently found pattern on the ring fingers (56%) in the current study, which coincides with the findings of several authors.[5,13,14,18,19,26] Loops were more frequently seen on the middle and little fingers, followed by the thumb. According to Varma RK et al. (2023),[14] loops were commonly seen on the little and middle fingers, followed by the thumb, while arches were most frequently observed in the little fingers. In the current study, no variation was observed in the pattern analysis between the left and right hand, with incidences of the loops, whorls, composites, and arches remaining consistent across both hands in that order [Table 2]. This observation is consistent with the results of Varma RK et al. (2023).[14] However, in the study by George SM et al. (2018),[24] loops were the most commonly encountered pattern across both hands, followed by arches and whorls. Comparison of the distribution of fingerprint patterns across different fingers gave statistically significant results (P < 0.001). However, further studies with larger samples are required to generalize the results.

Table 2.

Distribution of fingerprint patterns and digits of Right and Left Hands

Digits		Distribution of fingerprint patterns among Right and Left Hands								Total
		Arches	%	Whorls	%	Loops	%	Composites	%
Thumb	Left	0	0	11	22	29	58	10	20	50
	Right	1	2	13	26	29	58	7	14	50
	L+R	1	1	24	24	58	58	17	17	100
Index	Left	7	14	20	40	20	40	3	6	50
	Right	4	8	18	36	23	46	5	10	50
	L+R	11	11	38	38	43	43	8	8	100
Middle	Left	3	6	14	28	33	66	0	0	50
	Right	1	2	10	20	37	74	2	4	50
	L+R	4	4	24	24	70	70	2	2	100
Ring	Left	1	2	27	54	18	36	4	8	50
	Right	1	2	29	58	18	36	2	4	50
	L+R	2	2	56	56	36	36	6	6	100
Little	Left	0	0	12	24	35	70	3	6	50
	Right	1	2	13	26	30	60	6	12	50
	L+R	1	1	25	25	65	65	9	9	100
Total	Left	11	4.4	84	33.6	135	54	20	8	250
	Right	8	3.2	83	33.2	137	54.8	22	8.8	250
	L+R	19	3.8	167	33.4	272	54.4	42	8.4	500

χ²=81.1, df=27, P<0.001

The present study showed a statistically significant association between fingerprints and blood group (P < 0.001) [Table 3]. The distribution of basic fingerprint pattern was consistent across all ABO blood groups as shown by the studies done by several authors with loops being the most frequent, followed by whorls and arches.[1,3,4,11,26,27] Thakur et al.[23] noted that the though loop was the commonest pattern encountered; the frequency of the whorl pattern was higher, followed by loops and arches in all the ABO blood group system, except for the O blood group, where the loop was more common. In the present study, on analysis of the relationship between ABO blood grouping and fingerprint pattern, the predominant pattern observed among all blood groups was the loop pattern, except in the AB blood group which showed an increased prevalence of whorls (31.1%) contrary to the observations seen in other blood groups. This finding was consistent with the study by Tariq Al Habsi et al. (2023)[21] in the Omani population, where the predominant fingerprint pattern was loop, followed by whorls and then arches. The whorl pattern was associated with AB positive (60%) and O negative (45%). In the present study, arches (42.1%), whorls (31.1%), and composites (33.3%) were highest in blood groups A, AB, and B, respectively. The highest incidence of loops was observed in the B blood group (33.8%), agreeing with Singh B et al. and Raloti SK et al.[8,9] Meanwhile, Bharadwaja et al.[11] and Shrivastava M et al.[22] showed the A blood group to have the highest incidence of loops.

Table 3.

Distribution of fingerprint pattern within the ABO blood group in the population

Blood group	Fingerprint pattern				Total
	Arches (Count and % within blood group)	Whorls (Count and % within blood group)	Loops (Count and % within blood group)	Composites (Count and % within blood group)
A	8 42.1%	44 26.3%	83 30.5%	5 11.9%	140
B	7 36.8%	27 16.1%	92 33.8%	14 33.3%	140
AB	1 5.2%	52 31.1%	46 16.9%	11 2.2%	110
O	3 15.7%	44 26.3%	51 18.7	12 26.1%	110
Total	19	167	272	42	500

χ²=34.8, df=9, P<0.001

The present study found that loops (54.4%) were the most prevalent fingerprint pattern in both Rh +ve and Rh –ve groups, followed by whorls (33.4%), composites (8.4%), and arches (3.8%) [Table 4]. Notably, the Rh –ve group showed no arch pattern across all 10 fingers. These findings are consistent with those reported by other authors.[4,6,11,22,27]

Table 4.

Distribution of fingerprint pattern within the Rh blood group in the population

Rhesus factor	Fingerprint pattern				Total
	Arches	Whorls	Loops	Composites
Rh +ve	19 3.8%	156 31.2%	250 50%	35 7%	460 92%
Rh -ve	0 0%	11 2.2%	22 4.4%	7 1.4%	40 8%
Total	19 3.8%	167 33.4%	272 54.4%	42 8.4%	500 100%

χ²=6.39, df=3, P=0.094

The major limitation of this study has to do with the homogeneity of the sample population of Kerala, which limits the generalizability of the findings to a broader and diverse population of India, where there is a mixture of population of different ethnic backgrounds. Also, expanding the sample size could uncover further associations that were not evident in the current study due to the homogenous population, and also enhance their use in practical application on forensic identification.

Key messages

1. The study revealed a significant association between fingerprint patterns and ABO blood groups, with loops common across all, while whorls were predominant in the AB group.

2. The highest number of loops was seen in males, whereas for females, it was whorls.

3. No significant association was found between fingerprint patterns and sex.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.