B. Martinez

Fluctuating dermatoglyphic asymmetry: genetic and prenatal influences

Genetic and environmental prenatal factors influencing the fluctuating asymmetry of the a-b interdigital ridge count are examined. From the results obtained we can conclude that fluctuating asymmetry of the a-b interdigital ridge count is poorly influenced by genetic factors. We suggest that fluctuating asymmetry of dermatoglyphics provides a good measure of developmental stability in humans, especially for males. The results also indicate that random environmental factors, acting before the 19th week of embryonic development, could be related to the differential timing of maturation of the sexes.

Dermatoglyphic variation in Spanish Basque populations

The present study involves the evaluation of digital dermatoglyphic traits of 2185 unrelated individuals (1152 females and 1033 males) from 17 natural valleys of the four Basque provinces (Vizcaya, Guipúzcoa, Navarra, and Alava) in the Spanish Basque Country. Univariate intervalley and between-sex comparisons were carried out by means of chi-square contingency analysis for pattern types and by means of one-way analysis of variance for ridge counts. Multivariate intervalley comparison was carried out by means of correspondence analysis for pattern types and by principal component analysis for ridge counts. The results of this study are notable for the following findings: (1) in general, all variables are significantly heterogeneous among valley populations; (2) there was a greater differentiation among the valley populations than between sexes in one valley population; (3) affinities among the intervalley populations depend on the variables considered; (4) the valley populations from Vizcaya resemble those from the Pyrenees; (5) based on interprovince comparisons, the Vizcaya and Navarra samples are the closest; (6) in general, the valley samples from Alava are the worst clustered; (7) the universality of dermatoglyphic component structure fits better in males.

Chromosomal Fragility in a Behavioral Disorder

Numerous studies have shown there is consistent evidence implicating genetic factors in the etiology of autism. In some cases chromosomal abnormalities have been identified. One type of these abnormalities is gaps and breaks nonrandomly located in chromosomes, denominated fragile sites (FS). We cytogenetically analyzed a group of autistic individuals and a normal population, and we examined the FS found in both samples with the aim of (1) comparing their FS expression, (2) ascertaining whether any FS could be associated with our autistic sample, and (3) examining if there are differences between individual and pooled-data analyses. Different statistical methods were used to analyse the FS of pooled and individual data. Our results show that there are statistically significant differences in the spontaneous expression of breakages between patients and controls, with a minimal sex difference. Using the method for pooled data, eight autosomal FS have preferential expression in patients and five patients were found to be positive at FS Xq27.3. With the method per-individual analysis, four FS emerged as specific in our autistic sample. Inferences of FS from pooled data were different from those of individual data. The findings suggest that although analysis of pooled data is necessitated by the problem of sparse data, analysis of single individuals is essential to know the significance of FS in autism.

Characterization of digital dermatoglyphic features in Salazar Valley: comparison with other Basque valleys

Digital dermatoglyphics of a sample from the Basque Valley of Salazar, situated in the West of the Pyrenees, were analysed. The results showed bimanual differences in both sexes, and also sexual differences for both hands. The comparative study with other Basque valleys showed that, in spite of their supposed common origin, the geographic barriers and the isolation have generated a genetic/dermatoglyphic and linguistic differentiation.

Twin study of digital dermatoglyphic traits: Investigation of heritability

Digital patterns of a sample of monozygotic and dizygotic twins were analyzed to obtain heritability values for the four basic types of patterns: arch, tented arch, loops, and whorls. Loops have been separated according to their orientation radial or ulnar. To carry out this study, we used the Holzinger and Clark indices. The results show highest concordances for monozygotic twins except for ulnar loops of the left hand and radial ones of the right hand. Different values of heritability were found for the right and left hands, with finger I having the highest values.

Ridge hypoplasia and ridge dissociation: minor physical anomalies in autistic children.

Clin Genet 1993: 44: 107–108.

Cytogenetics of autosomal fragile sites: A Basque population study

Population cytogenetic data on autosomal fragile sites show differences among different ethnic groups. The Basques are an ancient population; their origin is not exactly known and many studies using several traits have shown peculiarities in the Basques. This is the first study about the incidence of autosomal fragile sites in a healthy Basque sample. The results show interindividual variability, no sex differences at a global level, but differences for some fragile sites. Compared with other populations, a higher incidence of rare autosomal fragile sites has been demonstrated (8%).