Variations of the sex ratio at birth (SRB) were investigated using maternity history data collected in demographic surveys conducted in sub-Saharan Africa. Thirty-three countries were covered, totaling about 2.0 million births. The average SRB was 1.034 and varied by ethnicity, birth order, and maternal age. The effect of maternal age was significant for younger mothers (12–19 years old) and older mothers (40–49 years old), with a decline in sex ratios with increasing maternal age in both cases. The effect of birth order was significant only for the 20–39-year-old women, with a decline in sex ratio with increasing birth order. These two effects were similar for the three main population groups identified: populations from southern, eastern, and central Africa (SRB = 1.015), populations from West Africa and Sahelian countries (SRB = 1.040), and populations from Nigeria and Ethiopia (SRB = 1.087). In contrast, no effect of marital duration was found.

The Indian subcontinent is characterized by the ancestral and cultural diversity of its people. Genetic input from several unique source populations and from the unique social architecture provided by the caste system has shaped the current genetic landscape of India. In the present study 200 individuals each from three upper-caste and four middle-caste Hindu groups and from two Muslim populations in North India were examined for 10 polymorphic Alu insertions (PAIs). The investigated PAIs exhibit high levels of polymorphism and average heterozygosity. Limited interpopulation variance and genetic flow in the present study suggest admixture. The results of this study demonstrate that, contrary to common belief, the caste system has not provided an impermeable barrier to genetic exchange among Indian groups.

The Muslim population of India is known for its historical and socioreligious significance. Literature on the genetic structure of this segment of India's population is scanty. Therefore we have investigated the allele frequency distribution of haptoglobin (HP) and transferrin (TF) phenotypes among the Muslims to explore the genetic diversity of the Muslim immigrant populations of Aligarh. Aligarh is a city in Uttar Pradesh, India (latitude 27°54′N, longitude 78°5′E), situated 130 km southeast of Delhi. The population is mainly represented by Muslim immigrants from the eastern, northern, southern, and western regions of India and from abroad. Differences in allele frequencies of both HP and TF were statistically significant for the population of immigrants from western India and insignificant for others. The alleles HP*2 and TF*C2 show maximum frequencies in the southern population (0.882 and 0.822, respectively) followed by the eastern population (0.862 and 0.807) and the northern population (0.806 and 0.650). In the northern population a third allele, TF*C3, is also detected, with a mean frequency of 0.044. The average heterozygosity (H_L) values for HP and TF are 0.273 and 0.361, respectively, and the pooled values for gene diversity parameters for both loci are H_T = 0.4294 ± 0.0351, H_S = 0.4225 ± 0.0271, and D_ST = 0.0069 ± 0.0051. The pooled G_ST value is 0.0153 ± 0.0108. The magnitude of these values indicates genetic similarity among the investigated populations. Our AMOVA results also demonstrate similarity among populations of the same geographic region. However, we note substantial differentiation among different regions (Φ_CT = 0.221). The UPGMA dendrogram shows a cluster between the eastern and southern populations, to which the northern population joins. Our results reveal genetic similarity among different immigrant populations, with the western population being the most distant. Therefore the present study on culturally, geographically, and linguistically different endogamous groups of Muslims may have significance in understanding their genetic relationship.

Isolation is a known force in evolutionary biology and one of the main factors in speciation. One of the main consequences of severe isolation is reduced mate choice, which results in the occurrence of inbreeding as a result of isolation. We investigated the effects of individual genome-wide heterozygosity measured as the multilocus heterozygosity (MLH) on biochemical markers of hemostasis and inflammation in 1,041 individuals from the island of Vis, Croatia, where inbreeding is prevalent and a wide range of variation in the genome-wide heterozygosity is expected. Assessment of individual genome-wide heterozygosity was based on genome-wide scans using 800 microsatellite (STR) and 317,503 single nucleotide (SNP) polymorphic markers in each examinee. In addition, for each examinee we defined a personal genetic history (PGH) based on genealogical records. The association between PGH and MLH and fibrinogen, D-dimer (Dd), von Willebrand factor (vWF), tissue plasminogen activator (tPA), and C-reactive protein (CRP) was performed with a mixed model, controlling for possible confounding effects. PGH was a significant predictor only for tPA (P < 0.001), whereas neither of the two MLH measures exhibited significant association with any of the investigated traits. The effects of individual genome-wide heterozygosity are most likely expressed in highly polygenically determined traits or in traits that are mediated by rare and recessive genetic variants. Weak associations between PGH and MLH and markers of hemostasis and inflammation suggest that their genetic control may not be highly polygenic and that they could be promising targets for genetic association studies.

Since the beginning of the Holocene, the Anatolian region has been a crossroads for populations and civilizations from Europe, Asia, and the Near to Middle East, with increasing interactions since the Bronze Age. In this context, we examine cranial discrete traits from a Byzantine population from southwest Turkey, excavated at the archeological site of Sagalassos; the site displays human occupation since the 12th millennium B.P. To investigate the biological history of this population, we analyzed the frequency distribution of 17 cranial discrete traits from Sagalassos and 27 Eurasian and African populations. Ward's clustering procedure and multidimensional scaling analyses of the standardized mean measure of divergence (MMD_st), based on trait frequencies, were used to represent the biological affinity between populations. Our results, considered within a large interpretive framework that takes into account the idea that populations are dynamic entities affected by various influences through time and space, revealed different strata of the Sagalassos biological history. Indeed, beyond an expected biological affinity of the Sagalassos population with eastern Mediterranean populations, we also detected affinities with sub-Saharan and northern and central European populations. We hypothesize that these affinity patterns in the Sagalassos biological package are the traces of the major migratory events that affected southwest Anatolia over the last millennia, as suggested from biological, archeological, and historical data.

The sequencing of the entire mitochondrial DNA belonging to haplogroup U2d reveals that this clade is defined by four coding-region mutations at positions 1700, 4025, 11893, and 14926. Phylogenetic analysis suggests that western Eurasian haplogroup U2d appears to be a sister clade with the Indo-Pakistani haplogroup U2c. Results of a phylogeographic analysis of published population data on the distribution of haplogroup U2d indicate that the presence of such mtDNA lineages in Europe may be mostly a consequence of medieval migrations of nomadic tribes from the Caucasus and eastern Europe to central Europe.

Hemoglobin profile studies have been carried out in four samples from different districts of Porto Velho (Rondônia State) in the western Amazonian region of Brazil: Candelária, Bate Estaca, Hemeron (at the State Blood Bank), and São Carlos. Samples from 337 unrelated individuals were collected during medical and paramedical team visits by professionals from the Instituto de Pesquisa em Patologia Tropical and the Centro de Pesquisa em Patologias Tropicais (both research institutes in tropical diseases). The aim of this study is to assess the frequency of alleles in the hemoglobin system, mainly alleles HB*A, *S, and *E. The overall phenotype frequencies were HB A,S = 0.025, HB A,E = 0.006, and HB A,A = 0.969. Samples from the blood bank subjects and samples from the homogeneous areas of São Carlos and Candelária plus Bate Estaca have a chi-square of heterogeneity of 6.383 (p = 0.041) and 8.406 (p = 0.015), respectively. The allele frequencies (HB*A = 0.984, HB*S = 0.012, and HB*E = 0.003) do not significantly differ from frequencies found in other Brazilian regions.

Several studies have suggested that fragile X syndrome (FRAXA), the most common inherited form of mental retardation, originated from a limited number of founder chromosomes. The aim of this study is to assess the genetic origin of fragile X syndrome in a Croatian population. We performed a haplotype analysis of the polymorphic loci DXS548 and FRAXAC1 in 18 unrelated fragile X and 56 control chromosomes. The AGG interspersion pattern of the FMR1 CGG repeat region was analyzed by sequencing. This is the first report on haplotype and AGG interspersion analysis of the fragile X syndrome gene in a Croatian population—the only eastern European population of Slavic origin analyzed so far. Our findings are intriguing, because they show a distinct distribution of the DXS548 and FRAXAC1 alleles in our fragile X population compared to other European fragile X populations. The DXS548/FRAXAC1 haplotype 194/154 (7–3), which is common among normal populations, was found to be the most frequent haplotype in our fragile X population as well. The AGG interspersion analysis indicated that AGG loss rather than haplotype may determine FMR1 allele instability. Our results suggest that no common ancestral X chromosome is associated with fragile X syndrome in the Croatian population studied. Further analysis of the origin of fragile X syndrome among other Slavic populations will be necessary to better define its eastern European distribution.