Fragile X syndrome is the most common form of inherited mental retardation. The molecular basis is usually the unstable expansion of a CGG repeat in the FMR1 gene. We previously analyzed a sample of two Basque valleys. In the present work we extend the study to another five isolated valleys. The results show that differences in factors implicated in CGG repeat instability—CGG repeat size, XS548/FRAXAC1 haplotypes, and AGG interspersion pattern—are present in the Basque populations analyzed.

Historically, a number of local Hindu caste groups have converted to Islam and formed religious endogamous groups. Therefore the local caste groups and religious communities in a region are expected to show genetic relatedness. In this study we investigate the genetic relationship between Tamil-speaking (Dravidian language) Muslims (Sunni), six endogamous Hindu castes, and a tribal ethnic group (Irulars) using 13 CODIS (Combined DNA Index System) autosomal microsatellite markers. Muslims show the highest average heterozygosity (0.405) compared to the other groups. The neighbor-joining tree and the multidimensional-scaling plot show clustering of Tamil-speaking Muslims with three caste groups (Gounder, Paraiyar, and Vanniyar), whereas the Irular tribe is separated out of the cluster.

A retrospective study was carried out to investigate the twinning rate and its correlates from January 1991 to December 2005 in 10 villages of the Rural Health Centre, Pohir, a field practice area of the Department of Community Medicine, Dayanand Medical College and Hospital, Ludhiana, Punjab, India. During this study period, 5,070 deliveries took place. A total of 5,017 singleton births and 53 sets of twins were recorded, giving a twinning rate of 10.45 per 1,000 total deliveries. Monozygotic and dizygotic twinning rates were estimated as 2.96 and 7.49 per 1,000 deliveries, respectively. The twinning rate was strongly associated with maternal age; the twinning rate for mothers between 30 and 34 years of age was about 10 times higher than the rate for mothers younger than 20 years. This variation was due to variation in dizygotic twinning; the rate of monozygotic twinning was almost constant for all ages. The twinning rate was highest at gestational order 4 or higher. The perinatal mortality rate among the twins was 173.1 per 1,000 total twin births and was significantly higher among the group in which diagnosis of twins was not done during the prenatal period. We should expect 1 twin birth per 100 births, and because perinatal mortality is alarmingly high in undiagnosed twin pregnancies, early recognition of twin pregnancy during prenatal visits and delivering in a health facility with adequately trained personnel should be encouraged.

Growth is a complex process composed of distinct phases over the course of childhood. Although the pubertal growth spurt has received the most attention from auxologists and pediatricians, the midchildhood growth spurt has been less well studied. The midchildhood growth spurt refers to a relatively small increase in growth velocity observed in some, but not necessarily all, children in early to middle childhood. If present, the midchildhood growth spurt typically occurs sometime between the ages of 4 and 8 years, well before the onset of the far more pronounced pubertal growth spurt. In this study we used a triple logistic curve-fitting method to fit individual growth curves to serial stature data from 579 healthy participants in the Fels Longitudinal Study, 479 of whom have been genotyped for about 400 short tandem repeat (STR) markers spanning the genome. We categorized individuals according to the presence or absence of a midchildhood growth spurt and then conducted heritability and genome-wide linkage analyses on the dichotomous trait. In the total sample of 579 individuals, 336 (58%) were found to have evidence of having had a midchildhood growth spurt. There was a marked sex difference in presence of the midchildhood growth spurt, however, with 232 of the 293 males (79%) having had a midchildhood growth spurt but just 104 of the 286 females (36%) having had one. Presence of a midchildhood growth spurt was found to have a significant heritability of 0.37 ± 0.14 (p = 0.003). Two quantitative trait loci with suggestive LOD scores were found: one at 12 cM on chromosome 17p13.2 (LOD = 2.13) between markers D17S831 and D17S938 and one at 85 cM on chromosome 12q14 (LOD = 2.06) between markers D12S83 and D12S326.

In this study we estimate relative genetic and environmental influences on head-related anthropometric phenotypes. The subject group consisted of 119 nuclear families living in Brussels, Belgium, and included 238 males and 236 females, ages 17 to 72 years. Two factor analyses with vari-max rotation (the first one related to facial measurements and the second one to overall head morphology) were used to analyze 14 craniofacial size traits. The resulting four synthetic traits [HFCF, VFCF, HDF1, and HDF2—horizontal (breadth) and vertical (height) facial factors and two head horizontal (breadth) factors, respectively] were used as summary variables. Maximum heritabilities (H²) were estimated for all studied traits, and variance components analysis was applied to determine the contribution of genetics and environment on the four craniofacial factors. In addition, we examined the covariations between the face (HFCF and VFCF) and head-related factors (HDF1 and HDF2), separately. Quantitative genetic analysis showed that HFCF, VFCF, HDF1, and HDF2 variation was appreciably attributable to additive genetic effects, with heritability (h²) estimates of 67.62%, 54.97%, 70.76%, and 65.05%, respectively. The three variance components reflecting a shared familial environment were nonsignificant for these four phenotypes. Bivariate analysis revealed significant additive and residual correlations for both pair of traits. The results confirm the existence of a significant genetic component determining the four craniofacial synthetic traits, and common genetic and environmental effects shared by the two face-related phenotypes and by the head-related ones.

We carried out an examination relying on six dimensions of 1,573 crania coming from the Great Hungarian Plain. The crania represent seven archeological periods: Sarmatian age (1–4th century), the period of transition (about 400–420), Hun and Gepidic epochs (about 420–455 and 455–567, respectively), early Avar age (about 568–670), late Avar period (about 670–895), the epoch of the Hungarian conquest and settlement (about 895–1000), and the Arpadian age (about 1000–1301). We were curious about the anatomical background behind cultural changes of the various populations that inhabited this area. After having noticed some discontinuities between the populations, as revealed by univariate analysis of single dimensions, we performed a principal-components analysis to see whether or not the diverse components showed eventual breaks in the sequence of the populations. Knowing that all the dominant populations had Asian roots, except for the Gepids of Germanic origin, we expected a considerable difference between the Gepidic population and all the other inhabitants. We also assumed that a conquest itself with a large-scale assimilation was unlikely to leave breaklike traits in anatomical patterns, except for aggressive conquests. We found that the second principal component (which correlated with cranial breadth and partly with height) showed a remarkable hiatus in both sexes between Gepids and early Avars. Having done a statistical proof (simultaneous tests for general linear hypotheses) of the observed phenomenon, we found that the gap referring to subsequent populations was significant only in males. A possible reason for this result is that the Avar conquest was much more radical than has been thought. In addition, considering that men were more likely to die in wars, women survived and were assimilated into the conquerors' populations with higher probability, so it is not surprising that the results of multicomparison tests are significant only in men.

The analysis of mtDNA haplogroup frequency in various populations is a tool for studying human history and population dynamics. The aim of this study is to map the frequency of major mtDNA haplogroups in 300 maternally unrelated individuals representing the Czech population of the central part of the Czech Republic. Eighteen polymorphic sites in the coding region of mtDNA were screened by PCR-RFLP to determine 11 mtDNA haplogroups and 5 subhaplogroups. The most frequent haplogroups were H (41%) and U (21%). Less frequent haplogroups were J and T, each with a frequency of 8%. Frequencies of other haplogroups (V, K, HV, W, preV, X, and I) did not exceed 5%. The results of our study reveal that the frequency of mtDNA haplogroups in the Czech population is similar to the frequencies obtained in other European countries, especially Poland, Germany, and Russia. On the contrary, significant differences in haplogroup frequency were found between the Czech and Finnish populations (haplogroups U, T, W) and populations from Bulgaria and Turkey (haplogroups H).