Annals of Human Biology
ISSN: 0301-4460 (Print) 1464-5033 (Online) Journal homepage: http://www.tandfonline.com/loi/iahb20
The analysis of whorls on specific fingertips with respect to sex, bilateral asymmetry, and genetic relationship A. Bener & F.C. Erk To cite this article: A. Bener & F.C. Erk (1979) The analysis of whorls on specific fingertips with respect to sex, bilateral asymmetry, and genetic relationship, Annals of Human Biology, 6:4, 349-356, DOI: 10.1080/03014467900003721 To link to this article: http://dx.doi.org/10.1080/03014467900003721
Published online: 09 Jul 2009.
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Date: 15 March 2016, At: 06:34
ANNALS OF HUMAN BIOLOGY, 1979, VOL. 6, NO. 4, 349 356
The analysis of whorls on specific fingertips with respect to sex, bilateral asymmetry, and genetic relationship A. BENER and F. C. ERK The Galton Laboratory, Department of Genetics and Biometry, University College London
Downloaded by [McMaster University] at 06:34 15 March 2016
Received 19 December 1978; revised 15 February 1979 Summary. In a sample of 539 Polish families, 1000 individuals (515 males and 485 females) were analysed to determine the distribution of whorl patterns on specific fingertips, to compare their frequencies in males and females, and to determine whether asymmetry of these dermatoglyphic pattern elements is genetically controlled. Whorls occur most commonly on digit IV on both hands and in both sexes. The difference between males and females for mean values of occurrence is not significant. Using the bimanual difference between hands (right minus left), the digital asymmetry was determined, and correlations with asymmetrical occurrence of whorls was made between parents and children, and between sibs, in all combinations. In each case, there was a positive correlation between pairs of relatives, demonstrating a genetic component in whorl determination and their asymmetrical occurrence.
1. Introduction Bilateral asymmetry in human morphology is demonstrable in various structures, including dermatoglyphic patterns on fingertips. The latter was first established quantitatively by Holt (1949, 1954), when she showed that mean ridge-counts are higher on right hands than on left hands. Mavalwala (1963) also recorded higher ridgecount values on the right hand than the left hand among members of the Parsi community in India. In 1970 Rashad and Mi reported no significant differences between males and females in bimanual differences in total ridge-counts. Finally, Bener (1979 a) analysed ulnar and radial loops for each digit on both hands and by sex. The means and variances for males were not significantly different from those for females. He showed that the determination of dermatoglyphic pattern elements of ulnar and radial loops on the two sides of the body had a genetic basis. In the present study an investigation was made to determine whether the pattern elements of whorls on fingertips likewise are genetically conditioned. The existence of bilateral asymmetry in this character is explored, and correlations between various degrees of genetic relationship and bimanual differences in the occurrence of whorls are calculated.
2. Materials and methods The present study is based on a collection of fingerprints from 1000 individuals (5 l 5 males and 485 females), drawn from a sample of 539 Polish families. These prints were originally collected by Loesch, who extended the topological formulation of dermatoglyphic description to include fingertip patterns (1975). In general, her description of fingertip patterns is based on the presence of single loops as pattern elements, which are in turn specified as radial or ulnar. The traditional 'whorl' or 'double loop' is thus a combination of two opposite loops, one radial and the other ulnar. 'Twin loops' whose cores point in the same direction are counted as two radial loops or two ulnar loops. Each pattern element is represented directly by the number two in order to avoid fractional values in describing unusual patterns. 0301 4460/79/06040349 $02.00 :~.I979 Taylor & Francis
I II III IV V
Left-hand fingertips
I II III IV V
Right-handfinoertips
Digit
Table 1.
513 512 514 514 515
513 512 514 514 515
No. of individuals
2.337 2,023 2.103 2.426 2.128
2"534 2"031 2"101 2.575 2"227
Me a n
0,026 0.038 0.028 0.025 0.020
0"023 0.041 0"028 0"023 0"022
Standard error of mean
0-368 0.762 0.412 0.334 0.217
0.284 0-887 0.430 0-287 0.257
Variance
0.607 0.873 0.642 0.578 0-465
0.533 0.942 0"655 0"536 0"507
Standard deviation
- 0.960 -0,417 - 1-116 - 0-527 -0.617
- 0.717 -0.344 - 1-106 - 0"876 - 0"318
Skewness
Analysis of dermatoglyphic pattern elements in whorls for each digit of males.
Downloaded by [McMaster University] at 06:34 15 March 2016
2.853 -0.382 3,266 2-160 6.729
0"782 -0'630 3"000 0'584 3'506
Kurtosis
o
I II IlI IV V
Digit
Table 3.
484 484 483 484 484
484 484 483 484 484
No. of individuals
2.254 1'971 2.037 2'367 2"134
2.407 2.047 2.037 2.497 2.136
Mean
0"032 0-041 0"030 0'027 0"020
0"028 0-039 0.029 0.026 0-021
Standard error of mean
0"508 0"852 0-459 0"369 0'207
0'395 0-774 0.430 0.329 0.233
Variance
0"718 0"923 0-677 0"607 0.455
0"628 0-879 0.655 0.573 0.483
Standard deviation
- 1-273 -0"481 - 1'290 - 0"953 - 0.408
- 1.177 -0-715 - 1.367 - 0.949 - 0.651
Skewness
Analysis of dermatoglyphic pattern elements in whorls for each digit of females.
2"696 -0.718 3"167 2"532 6'318
2"905 -0'141 3.724 1-710 6.041
Kurtosis
513 512 514 514 515
No.
2-534 2.031 2"101 2-575 2-227
R
R
L
2"337 0 " 1 9 7 2"023 0 " 0 0 8 2'103 -0"002 2 - 4 2 6 0.149 2"i28 0'099
L
Mean
0.040 0"043 0"036 0.036 0"033
SEM (R-L)
Males
0.284 0-887 0.430 0-287 0-257
R 0-368 0"762 0-412 0-334 0"217
L
0.832 0.964 0.682 0.676 0.565
R-L
Variance
484 484 483 484 484
No.
2"407 2.047 2'037 2.497 2"136
R
2'254 1"971 2"037 2"367 2-134
L
Mean
0"040 0'042 0"035 0'040 0'031
SEM L (R-L) 0-153 0"076 0"000 0-013 0-002
R
Females
0'395 0'774 0'430 0"329 0"233
R
0'508 0'852 0"459 0-369 0"207
L
Variance
0-813 0-875 0"619 0"802 0'467
R-L
Comparison of males and females with respect to mean fingertip counts of whorl pattern elements for each digit on each hand, together with bimanual (right minus left) differences.
I II IlI IV V
Left-hand fingertips
I II III IV V
Right-hand fingertips
Digit
Table 2.
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t~
352
A. Bener and F. C. Erk
This descriptive method was applied to whorls in the broad sense, and includes traditional whorls, double loops, and composite patterns on each digit on both the right and left hands. Mean values, mean differences between the two hands, and the variances of these, were calculated for each digit; similar comparisons were made for corresponding digits in males and females. The calculations were made on the IBM 360/65 computer at the University College London Computer Centre.
Downloaded by [McMaster University] at 06:34 15 March 2016
3.
Results The principal results are summarized in tables 1 to 6. The mean, standard error of mean, variance, standard deviation, skewness, and kurtosis are calculated for the whorl components of fingertip patterns for each digit of both hands in both sexes. These values are presented in table 1 for males and in table 2 for females. As a measure of the bimanual differences for this character, in table 3 the means and variances of individual digits for each hand and for each sex are given, together with the mean differences between the two hands and the variances of those differences. In table 4 each digit is compared with the same digit in the opposite sex, and the differences between like hands in the two sexes are calculated. The correlations between relatives for the occurrence of whorl patterns are shown in table 5 for each digit. The bimanual difference is determined separately for the members of each pair of a relationship and correlations between the two are then calculated; these correlations are given in table 6. Table 4. Comparisonof like hands in males and femaleswith respect to mean fingertip counts of whorl pattern elements on each digit. Right hands Digit I II III IV v 4.
No. of No. of m a l e s females 513 512 514 514 515
484 484 483 484 484
d'
~?
d- ~
LeR hands d
~
~-
2.534 2.407 0.127 2.337 2.254 0.083 2-031 2.047 -0.016 2.023 1.971 0-052 2.101 2.037 0.064 2-103 2.037 0.066 2.575 2.497 0.078 2.426 2.367 0-059 2.227 2-136 0.091 2.128 2.134 -0.006
Discussion The problem of the nature of genetic control of pattern development in dermatoglyphics can be best approached at present by exploring various aspects of pattern occurrence, including frequency on specific digits, relation to sex of individual, and correlation with degree of genetic relationship. In this report the most complex of patterns, the whorl, which is made up of two contributing pattern elements ('loops' in Loesch's (1975) descriptive terminology), is analysed both as it occurs on specific digits in individuals of both sexes, and as the pattern correlates with its occurrence on the same digit in relatives. F r o m the analyses in tables 1 and 2, it can be seen that the whorl pattern is distributed rather evenly on.ihe ten digits, with the highest value consistently on digit IV on both hands and in both sexes. The lowest value likewise is for digit II on both hands in both sexes, with the other digits showing intermediate values. These conclusions are consistent with earlier calculations of ridge-count correlation coefficients a m o n g all possible fingers by Holt (1951, 1958), who found the highest values of all between right IV and left IV in both males and females.
Downloaded by [McMaster University] at 06:34 15 March 2016
Genetics and asymmetry of whorls' on fingertips
353
To examine bimanual-differences as a measure of developmental, and perhaps genetic, asymmetry, mean values and variances of pattern element counts were compared both within (table 3) and between the sexes (table 4). Using ridge-counts as a quantitative measure of asymmetry, Holt (1949, 1954, 1958) and Mavalwala (1963) found that mean counts are usually greater on right hands than on left hands for both males and females. Bener (1979 a) has shown for ulnar and radial loops that the means are usually higher on individual right digits than on corresponding left digits in both males and females. As can be seen from table 3, this generalization also holds for whorls, with the single exception of digit III in males; in females there are no exceptions to the dominance of the right digits, but again digit III shows equal means, so that the bimanual differences for whorls are least in the central digit of the hand. The variances for right-hand fingers are greater in males on digits II, III, and V, but in females only digit V has a greater variance on the right hand than the left. When the differences between the means for each finger in males and females are compared (table 4), the means for males are generally greater than for females. The exceptions are seen in digit ii on right hands, and in digit V on left hands. This would indicate a somewhat larger number of pattern elements in males than in females, which would harmonize with the earlier data on ridge-count comparisons between the sexes (Holt 1949). It is of historical interest that Galton (1892) had already pointed out that the frequency with which any pattern occurs on digits I and IV differs greatly on the two hands. In the present study the difference between the two hands is indeed greatest for digit I in both males and females; the difference for digit IV is second greatest in males, and third greatest in females (that of digit II being larger). The theoretical correlation between relatives for autosomal and sex-linked loci have been found and utilized by Fisher (1918) and the midparent-child correlation has been calculated by Bener (1979 b). The actual correlations, using present methods of analysis, are presented in table 5. It is seen that the father son correlation is usually less than the father daughter correlation, although the mother-son correlation is often greater than the mother-daughter one. Further, b r o t h e ~ b r o t h e r correlations are much higher than sister-sister correlations, and parent-child correlations are usually greater than sil~sib correlations. Since the proportion of genes shared (I) is the same, it might be inferred that non-genetic factors, perhaps maternal or paternal effects, play a role in the expression of pattern. A further analysis was made of correlations between relatives for bimanual differences (right minus left) in whorl pattern elements. Table 6 shows that these correlations are small but usually positive, suggesting that there is some genetic contribution to bilateral asymmetry, thus agreeing with earlier work by Holt (1954) and by Bener (1979 a). The very low correlations between mother and daughter are striking; they are about the same as parent-parent (i.e., unrelated persons) correlations, thus demonstrating a remarkable absence of maternal influence through either egg organization or maternal-fetal hormonal effects. If X-linked genes are involved in these demonstrated differences, the father-son correlation would be expected to be lower than fathe~daughter, mother-son, or mother-daughter correlations (Li 1976), in all of which there is X chromosome contribution. There is little evidence of this except where bimanual differences are concerned, so X-linkage does not seem to be involved. Likewise genetic dominance, which would increase sib-sib correlations above parent-child and midparent-child correlations, does not seem to be operating. It thus appears that polygenic autosomal
I II III IV V
L@-hand digit
I II IlI IV V
0.19 0.25 0-11 0-28 0.20
0.20 0.33 0.24 0.28 0.21
249
No. of pairs
Right-hand diyit
r=}
Father son
Relationship: Theoretical correlations for additive genetic characters
0.22 0-17 0-19 0.25 0.45
0.25 0.24 0.25 0.34 0.34
218
r=½
0.16 0.26 0.35 0-28 0.32
0.19 0.37 0.16 0.27 0-20
285
r=½
0-19 0.18 0.19 0.21 0.16
0-14 0-18 0.15 0.13 0-19
219
Motherdaughter
0.19 0.22 0-22 0.26 0.28
0.19 0.29 0.20 0.26 0.23
971
Parentchild
0.19 0.26 0.21 0.29 0.30
0.19 (~35 0.24 0.28 0.22
534
=4½
Midparentson
0.20 0.20 0-20 0-26 0.33
0.21 0.24 0.25 0-26 0.30
437
Midparentdaughter
0-27 0-31 0.30 0.36 0.40
0.27 0-41 0.28 0.36 0-33
971
Midparent child
0.05 0-43 0.25 0.25 0.30
0.28 0-28 0.15 0.20 0.19
211
0-14 0.22 0.19 0.30 0.22
0.14 0-22 0.11 0.15 0-26
286
Brother-Brotherbrother sister
0-04 0.08 -0.14 - 0.00 0.05
0.01 0.09 0.08 0.13 0.06
97
Sistersister
Correlations between relatives with respect to fingertip counts for whorl pattern elements on each digit.
Father- Mother daughter son
Table 5.
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0.11 0-25 0.17 0-25 0-22
0.16 0-22 0.12 0.16 0.22
594
Sibsib
-0.02 -0.12 0.04 - 0-04 -0.01
0.00 0.12 0.09 0.01 -0.02
178
r=0
Parentparent
a~
ta~ tm 4~
f,3
249
0.09 0-11 0.12 0-17 0.07
No. of pairs
Digit I II III IV V
"
Father= son r=½
0.15 0-08 0-16 0-16 0.03
218
0.13 0.26 0.11 0-13 0.05
285
Father Mother daughter son r= ½ r=½
0-00 0.07 0.04 0.03 0.07
219
Mother daughter r=½
0.10 0.14 0.11 0.12 0-06
971
Parent child r=½
0.12 0.18 0.14 0.16 0-06
534
Midparent son r =,]'½
0.09 0.10 0-13 0-10 0-06
437
Midparent daughter r=x/½
0.14 0.20 0.15 0.18 0.08
971
Midparent child r=~/½
0.17 0-06 0;02 005 0.06
211
Brother brother r=½
0.03 0.09 0-01 0-04 0-11
286
Brother sister r=½
-0-05 -0.00 0.10 0-06 0.14
97
Sister sister r=½
0.06 0.07 0-02 0.01 0-10
594
Sib sib r=½
Correlations between relatives with respect to bimanual (right minus left) differences for whorl pattern elements on each digit.
Relationship: Theoretical correlations for additive genetic characters:
Table 6.
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0.01 0-08 0.12 0.01 0-01
178
Parent parent r=0
t.a3
%
a:
ISSN: 0301-4460 (Print) 1464-5033 (Online) Journal homepage: http://www.tandfonline.com/loi/iahb20
The analysis of whorls on specific fingertips with respect to sex, bilateral asymmetry, and genetic relationship A. Bener & F.C. Erk To cite this article: A. Bener & F.C. Erk (1979) The analysis of whorls on specific fingertips with respect to sex, bilateral asymmetry, and genetic relationship, Annals of Human Biology, 6:4, 349-356, DOI: 10.1080/03014467900003721 To link to this article: http://dx.doi.org/10.1080/03014467900003721
Published online: 09 Jul 2009.
Submit your article to this journal
Article views: 4
View related articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=iahb20 Download by: [McMaster University]
Date: 15 March 2016, At: 06:34
ANNALS OF HUMAN BIOLOGY, 1979, VOL. 6, NO. 4, 349 356
The analysis of whorls on specific fingertips with respect to sex, bilateral asymmetry, and genetic relationship A. BENER and F. C. ERK The Galton Laboratory, Department of Genetics and Biometry, University College London
Downloaded by [McMaster University] at 06:34 15 March 2016
Received 19 December 1978; revised 15 February 1979 Summary. In a sample of 539 Polish families, 1000 individuals (515 males and 485 females) were analysed to determine the distribution of whorl patterns on specific fingertips, to compare their frequencies in males and females, and to determine whether asymmetry of these dermatoglyphic pattern elements is genetically controlled. Whorls occur most commonly on digit IV on both hands and in both sexes. The difference between males and females for mean values of occurrence is not significant. Using the bimanual difference between hands (right minus left), the digital asymmetry was determined, and correlations with asymmetrical occurrence of whorls was made between parents and children, and between sibs, in all combinations. In each case, there was a positive correlation between pairs of relatives, demonstrating a genetic component in whorl determination and their asymmetrical occurrence.
1. Introduction Bilateral asymmetry in human morphology is demonstrable in various structures, including dermatoglyphic patterns on fingertips. The latter was first established quantitatively by Holt (1949, 1954), when she showed that mean ridge-counts are higher on right hands than on left hands. Mavalwala (1963) also recorded higher ridgecount values on the right hand than the left hand among members of the Parsi community in India. In 1970 Rashad and Mi reported no significant differences between males and females in bimanual differences in total ridge-counts. Finally, Bener (1979 a) analysed ulnar and radial loops for each digit on both hands and by sex. The means and variances for males were not significantly different from those for females. He showed that the determination of dermatoglyphic pattern elements of ulnar and radial loops on the two sides of the body had a genetic basis. In the present study an investigation was made to determine whether the pattern elements of whorls on fingertips likewise are genetically conditioned. The existence of bilateral asymmetry in this character is explored, and correlations between various degrees of genetic relationship and bimanual differences in the occurrence of whorls are calculated.
2. Materials and methods The present study is based on a collection of fingerprints from 1000 individuals (5 l 5 males and 485 females), drawn from a sample of 539 Polish families. These prints were originally collected by Loesch, who extended the topological formulation of dermatoglyphic description to include fingertip patterns (1975). In general, her description of fingertip patterns is based on the presence of single loops as pattern elements, which are in turn specified as radial or ulnar. The traditional 'whorl' or 'double loop' is thus a combination of two opposite loops, one radial and the other ulnar. 'Twin loops' whose cores point in the same direction are counted as two radial loops or two ulnar loops. Each pattern element is represented directly by the number two in order to avoid fractional values in describing unusual patterns. 0301 4460/79/06040349 $02.00 :~.I979 Taylor & Francis
I II III IV V
Left-hand fingertips
I II III IV V
Right-handfinoertips
Digit
Table 1.
513 512 514 514 515
513 512 514 514 515
No. of individuals
2.337 2,023 2.103 2.426 2.128
2"534 2"031 2"101 2.575 2"227
Me a n
0,026 0.038 0.028 0.025 0.020
0"023 0.041 0"028 0"023 0"022
Standard error of mean
0-368 0.762 0.412 0.334 0.217
0.284 0-887 0.430 0-287 0.257
Variance
0.607 0.873 0.642 0.578 0-465
0.533 0.942 0"655 0"536 0"507
Standard deviation
- 0.960 -0,417 - 1-116 - 0-527 -0.617
- 0.717 -0.344 - 1-106 - 0"876 - 0"318
Skewness
Analysis of dermatoglyphic pattern elements in whorls for each digit of males.
Downloaded by [McMaster University] at 06:34 15 March 2016
2.853 -0.382 3,266 2-160 6.729
0"782 -0'630 3"000 0'584 3'506
Kurtosis
o
I II IlI IV V
Digit
Table 3.
484 484 483 484 484
484 484 483 484 484
No. of individuals
2.254 1'971 2.037 2'367 2"134
2.407 2.047 2.037 2.497 2.136
Mean
0"032 0-041 0"030 0'027 0"020
0"028 0-039 0.029 0.026 0-021
Standard error of mean
0"508 0"852 0-459 0"369 0'207
0'395 0-774 0.430 0.329 0.233
Variance
0"718 0"923 0-677 0"607 0.455
0"628 0-879 0.655 0.573 0.483
Standard deviation
- 1-273 -0"481 - 1'290 - 0"953 - 0.408
- 1.177 -0-715 - 1.367 - 0.949 - 0.651
Skewness
Analysis of dermatoglyphic pattern elements in whorls for each digit of females.
2"696 -0.718 3"167 2"532 6'318
2"905 -0'141 3.724 1-710 6.041
Kurtosis
513 512 514 514 515
No.
2-534 2.031 2"101 2-575 2-227
R
R
L
2"337 0 " 1 9 7 2"023 0 " 0 0 8 2'103 -0"002 2 - 4 2 6 0.149 2"i28 0'099
L
Mean
0.040 0"043 0"036 0.036 0"033
SEM (R-L)
Males
0.284 0-887 0.430 0-287 0-257
R 0-368 0"762 0-412 0-334 0"217
L
0.832 0.964 0.682 0.676 0.565
R-L
Variance
484 484 483 484 484
No.
2"407 2.047 2'037 2.497 2"136
R
2'254 1"971 2"037 2"367 2-134
L
Mean
0"040 0'042 0"035 0'040 0'031
SEM L (R-L) 0-153 0"076 0"000 0-013 0-002
R
Females
0'395 0'774 0'430 0"329 0"233
R
0'508 0'852 0"459 0-369 0"207
L
Variance
0-813 0-875 0"619 0"802 0'467
R-L
Comparison of males and females with respect to mean fingertip counts of whorl pattern elements for each digit on each hand, together with bimanual (right minus left) differences.
I II IlI IV V
Left-hand fingertips
I II III IV V
Right-hand fingertips
Digit
Table 2.
Downloaded by [McMaster University] at 06:34 15 March 2016
t~
352
A. Bener and F. C. Erk
This descriptive method was applied to whorls in the broad sense, and includes traditional whorls, double loops, and composite patterns on each digit on both the right and left hands. Mean values, mean differences between the two hands, and the variances of these, were calculated for each digit; similar comparisons were made for corresponding digits in males and females. The calculations were made on the IBM 360/65 computer at the University College London Computer Centre.
Downloaded by [McMaster University] at 06:34 15 March 2016
3.
Results The principal results are summarized in tables 1 to 6. The mean, standard error of mean, variance, standard deviation, skewness, and kurtosis are calculated for the whorl components of fingertip patterns for each digit of both hands in both sexes. These values are presented in table 1 for males and in table 2 for females. As a measure of the bimanual differences for this character, in table 3 the means and variances of individual digits for each hand and for each sex are given, together with the mean differences between the two hands and the variances of those differences. In table 4 each digit is compared with the same digit in the opposite sex, and the differences between like hands in the two sexes are calculated. The correlations between relatives for the occurrence of whorl patterns are shown in table 5 for each digit. The bimanual difference is determined separately for the members of each pair of a relationship and correlations between the two are then calculated; these correlations are given in table 6. Table 4. Comparisonof like hands in males and femaleswith respect to mean fingertip counts of whorl pattern elements on each digit. Right hands Digit I II III IV v 4.
No. of No. of m a l e s females 513 512 514 514 515
484 484 483 484 484
d'
~?
d- ~
LeR hands d
~
~-
2.534 2.407 0.127 2.337 2.254 0.083 2-031 2.047 -0.016 2.023 1.971 0-052 2.101 2.037 0.064 2-103 2.037 0.066 2.575 2.497 0.078 2.426 2.367 0-059 2.227 2-136 0.091 2.128 2.134 -0.006
Discussion The problem of the nature of genetic control of pattern development in dermatoglyphics can be best approached at present by exploring various aspects of pattern occurrence, including frequency on specific digits, relation to sex of individual, and correlation with degree of genetic relationship. In this report the most complex of patterns, the whorl, which is made up of two contributing pattern elements ('loops' in Loesch's (1975) descriptive terminology), is analysed both as it occurs on specific digits in individuals of both sexes, and as the pattern correlates with its occurrence on the same digit in relatives. F r o m the analyses in tables 1 and 2, it can be seen that the whorl pattern is distributed rather evenly on.ihe ten digits, with the highest value consistently on digit IV on both hands and in both sexes. The lowest value likewise is for digit II on both hands in both sexes, with the other digits showing intermediate values. These conclusions are consistent with earlier calculations of ridge-count correlation coefficients a m o n g all possible fingers by Holt (1951, 1958), who found the highest values of all between right IV and left IV in both males and females.
Downloaded by [McMaster University] at 06:34 15 March 2016
Genetics and asymmetry of whorls' on fingertips
353
To examine bimanual-differences as a measure of developmental, and perhaps genetic, asymmetry, mean values and variances of pattern element counts were compared both within (table 3) and between the sexes (table 4). Using ridge-counts as a quantitative measure of asymmetry, Holt (1949, 1954, 1958) and Mavalwala (1963) found that mean counts are usually greater on right hands than on left hands for both males and females. Bener (1979 a) has shown for ulnar and radial loops that the means are usually higher on individual right digits than on corresponding left digits in both males and females. As can be seen from table 3, this generalization also holds for whorls, with the single exception of digit III in males; in females there are no exceptions to the dominance of the right digits, but again digit III shows equal means, so that the bimanual differences for whorls are least in the central digit of the hand. The variances for right-hand fingers are greater in males on digits II, III, and V, but in females only digit V has a greater variance on the right hand than the left. When the differences between the means for each finger in males and females are compared (table 4), the means for males are generally greater than for females. The exceptions are seen in digit ii on right hands, and in digit V on left hands. This would indicate a somewhat larger number of pattern elements in males than in females, which would harmonize with the earlier data on ridge-count comparisons between the sexes (Holt 1949). It is of historical interest that Galton (1892) had already pointed out that the frequency with which any pattern occurs on digits I and IV differs greatly on the two hands. In the present study the difference between the two hands is indeed greatest for digit I in both males and females; the difference for digit IV is second greatest in males, and third greatest in females (that of digit II being larger). The theoretical correlation between relatives for autosomal and sex-linked loci have been found and utilized by Fisher (1918) and the midparent-child correlation has been calculated by Bener (1979 b). The actual correlations, using present methods of analysis, are presented in table 5. It is seen that the father son correlation is usually less than the father daughter correlation, although the mother-son correlation is often greater than the mother-daughter one. Further, b r o t h e ~ b r o t h e r correlations are much higher than sister-sister correlations, and parent-child correlations are usually greater than sil~sib correlations. Since the proportion of genes shared (I) is the same, it might be inferred that non-genetic factors, perhaps maternal or paternal effects, play a role in the expression of pattern. A further analysis was made of correlations between relatives for bimanual differences (right minus left) in whorl pattern elements. Table 6 shows that these correlations are small but usually positive, suggesting that there is some genetic contribution to bilateral asymmetry, thus agreeing with earlier work by Holt (1954) and by Bener (1979 a). The very low correlations between mother and daughter are striking; they are about the same as parent-parent (i.e., unrelated persons) correlations, thus demonstrating a remarkable absence of maternal influence through either egg organization or maternal-fetal hormonal effects. If X-linked genes are involved in these demonstrated differences, the father-son correlation would be expected to be lower than fathe~daughter, mother-son, or mother-daughter correlations (Li 1976), in all of which there is X chromosome contribution. There is little evidence of this except where bimanual differences are concerned, so X-linkage does not seem to be involved. Likewise genetic dominance, which would increase sib-sib correlations above parent-child and midparent-child correlations, does not seem to be operating. It thus appears that polygenic autosomal
I II III IV V
L@-hand digit
I II IlI IV V
0.19 0.25 0-11 0-28 0.20
0.20 0.33 0.24 0.28 0.21
249
No. of pairs
Right-hand diyit
r=}
Father son
Relationship: Theoretical correlations for additive genetic characters
0.22 0-17 0-19 0.25 0.45
0.25 0.24 0.25 0.34 0.34
218
r=½
0.16 0.26 0.35 0-28 0.32
0.19 0.37 0.16 0.27 0-20
285
r=½
0-19 0.18 0.19 0.21 0.16
0-14 0-18 0.15 0.13 0-19
219
Motherdaughter
0.19 0.22 0-22 0.26 0.28
0.19 0.29 0.20 0.26 0.23
971
Parentchild
0.19 0.26 0.21 0.29 0.30
0.19 (~35 0.24 0.28 0.22
534
=4½
Midparentson
0.20 0.20 0-20 0-26 0.33
0.21 0.24 0.25 0-26 0.30
437
Midparentdaughter
0-27 0-31 0.30 0.36 0.40
0.27 0-41 0.28 0.36 0-33
971
Midparent child
0.05 0-43 0.25 0.25 0.30
0.28 0-28 0.15 0.20 0.19
211
0-14 0.22 0.19 0.30 0.22
0.14 0-22 0.11 0.15 0-26
286
Brother-Brotherbrother sister
0-04 0.08 -0.14 - 0.00 0.05
0.01 0.09 0.08 0.13 0.06
97
Sistersister
Correlations between relatives with respect to fingertip counts for whorl pattern elements on each digit.
Father- Mother daughter son
Table 5.
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0.11 0-25 0.17 0-25 0-22
0.16 0-22 0.12 0.16 0.22
594
Sibsib
-0.02 -0.12 0.04 - 0-04 -0.01
0.00 0.12 0.09 0.01 -0.02
178
r=0
Parentparent
a~
ta~ tm 4~
f,3
249
0.09 0-11 0.12 0-17 0.07
No. of pairs
Digit I II III IV V
"
Father= son r=½
0.15 0-08 0-16 0-16 0.03
218
0.13 0.26 0.11 0-13 0.05
285
Father Mother daughter son r= ½ r=½
0-00 0.07 0.04 0.03 0.07
219
Mother daughter r=½
0.10 0.14 0.11 0.12 0-06
971
Parent child r=½
0.12 0.18 0.14 0.16 0-06
534
Midparent son r =,]'½
0.09 0.10 0-13 0-10 0-06
437
Midparent daughter r=x/½
0.14 0.20 0.15 0.18 0.08
971
Midparent child r=~/½
0.17 0-06 0;02 005 0.06
211
Brother brother r=½
0.03 0.09 0-01 0-04 0-11
286
Brother sister r=½
-0-05 -0.00 0.10 0-06 0.14
97
Sister sister r=½
0.06 0.07 0-02 0.01 0-10
594
Sib sib r=½
Correlations between relatives with respect to bimanual (right minus left) differences for whorl pattern elements on each digit.
Relationship: Theoretical correlations for additive genetic characters:
Table 6.
Downloaded by [McMaster University] at 06:34 15 March 2016
0.01 0-08 0.12 0.01 0-01
178
Parent parent r=0
t.a3
%
a:
