Type 2 diabetes mellitus (T2DM) is a common complex phenotype that by the year 2010 is predicted to affect 221 million people globally. In the present study we performed a genome-wide linkage scan using the allele-sharing statistic S_all implemented in Allegro and a novel two-dimensional genome-wide strategy implemented in Merloc that searches for pairwise interaction between genetic markers located on different chromosomes linked to T2DM. In addition, we used a robust score statistic from the newly developed QTL-ALL software to search for linkage to variation in adult height. The strategies were applied to a study sample consisting of 238 sib-pairs affected with T2DM from American Samoa. We did not detect any genome-wide significant susceptibility loci for T2DM. However, our two-dimensional linkage investigation detected several loci pairs of interest, including 11q22 and 21q21, 9q21 and 11q22, 1p22–p21 and 4p15, and 4p15 and 15q11–q14, with a two-loci maximum LOD score (MLS) greater than 2.00. Most detected individual loci have previously been identified as susceptibility loci for diabetes-related traits. Our two-dimensional linkage results may facilitate the selection of potential candidate genes and molecular pathways for further diabetes studies because these results, besides providing candidate loci, also demonstrate that polygenic effects may play an important role in T2DM. Linkage was detected (p value of 0.005) for variation in adult height on chromosome 9q31, which was reported previously in other populations. Our finding suggests that the 9q31 region may be a strong quantitative trait locus for adult height, which is likely to be of importance across populations.

A good knowledge of the seasonal variation during normal years is of fundamental importance for analyses of the effects of wars, famines, epidemics, or similar privations on births and deaths. In this study we consider data from the Åland Islands (Finland) for 1650–1950. During the period 1650–1793 there are subperiods with missing data for all parishes, and consequently the total data for the Åland Islands for this period have to be estimated using available data. For the period 1794–1950 the registered data seem to be complete and reliable, but the war year 1809 shows a marked deficit of births. During the last decades of the 19th century the number of births increases markedly and after that shows a strong decrease. After the 1930s births increase again. To allow seasonality comparisons between the Åland Islands as a whole and its subregions, we base our studies on seasonal indexes. There is a markedly decreasing temporal trend in the seasonal variation of births for the Åland Islands as a whole, but the general pattern remains mainly the same, having two peaks, one in March-April and one in September-October. For the period 1901–1950 the seasonal variation almost disappeared. The strength of the seasonal variation in births shows regional differences, but the general pattern is mainly the same. The outermost parish, Kökar, an isolate of its own, shows the strongest seasonal variation in births. The annual number of deaths shows some marked peaks, especially in the war year 1809. For both sexes there are marked peaks in 1809, indicating that the deaths were mainly caused by epidemic diseases rather than by killing in battles. For mortality a decreasing trend in the seasonal variation is observed during 1650–1750, but after 1751–1800 the strength of seasonality shows an increasing trend and a sinusoidal pattern.

We carried out an exploratory historical biology study using temporally distinguished groups of predynastic–Early Dynastic male crania from the region of Upper Egypt. The objectives were, first, to determine the overall pattern of phenetic affinity between temporally sequential series and in relation to the earliest series and, second, to explore the possible meanings of the pattern of relationship to sociohistorical change. The cranial series were designated early predynastic, late predynastic, terminal predynastic, and Dynasty I. Craniometric phenetic affinity was ascertained using Mahalanobis distances; a 5% level of probability was chosen for significance. The distance matrix values were ordered into hierarchies of dissimilarity from each series (distance hierarchies) and tabulated for time-successive groups, including the temporally earliest series (i.e., serialized by time). The principal observations were as follows. The overall pattern was not one in which the values between all series were statistically insignificant; nor was it one of consistent sequential increase of biological distance from the earliest series. There was a notable and statistically significant distance between the early and late predynastic groups, with the late and terminal predynastic groups mutually having the lowest and statistically insignificant distances with each other. The value between the terminal predynastic and Dynasty I series was generally larger than the values between other groups and was statistically significant. The overall pattern is possibly consistent with archeological interpretations that postulate increasing intraregional interactions during the late and terminal predynastic periods and the rise of an Egyptian state that eventually included northern Egypt.

The case-control association study design has been extensively used for elucidating the genetic basis of complex traits. Considerable variation in frequencies of various gene polymorphisms has been reported across different populations and ethnic groups. Thus before beginning such studies, one must know the gene variants that exist in the population. Such information is not available for the ethnically distinct Indian population, which, on the basis of the languages spoken, can be further subdivided into Indo-Europeans (North Indians) and Dravidians (South Indians). In this study we provide information on allele and genotype frequencies, pairwise linkage disequilibrium, and predominant haplotypes in two populations (North India, n = 96 South India, n = 96) for several of the commonly investigated polymorphisms in the oxidative stress pathway genes. Of the 33 polymorphisms in 19 genes tested, significant differences in allele and genotype frequencies between the two populations were observed for SOD3 Ala58Thr, UCP1 − 3826 C/T, NOS3 − 786 T/C, and TNFA − 308 G/A polymorphisms.

Methionine homozygosity at codon 129 of the prion protein gene is a risk factor for Creutzfeldt-Jakob disease. Knowledge of M129V polymorphism in normal populations may contribute to a better understanding of prion diseases. M129V polymorphism was studied in 2,201 normal subjects, originating from 15 populations from Europe and the Middle East. Mean heterozygosity in these populations is 38.9%, and there is some significant geographic heterogeneity between them. A comparison of M129 allele frequencies in these 15 populations to those already published for 8 European countries plus Turkey shows significant correlations with both latitude (r = − 0.77) and longitude (r = 0.69). The geographic map of methionine allele frequencies indicates an east-west gradient of decreasing methionine allele values from the Middle East to Western Europe.

Polymorphism frequencies of the dopamine transporter gene (DAT1) hypervariable region have been analyzed in a sample of Italian and Ivory Coast individuals. The 3′untranslated region (UTR) of DAT1 includes a variable number of tandem repeats (VNTR) of a 40-bp monomer, ranging from 3 to 13 repeats in Caucasian and African populations. In our sample we found alleles with 3 to 16 repeats, and the most common alleles were the 10-repeat (DAT1*10) and the 9-repeat (DAT1*9) alleles. We also found two rare alleles in the Italian population and four in the Ivory Coast population. For the first time the new allele DAT1*16 is described in the Ivorians. The Ivory Coast population was not in Hardy-Weinberg equilibrium for the DAT1 locus because of a deficit of heterozygote genotypes. The observed heterozygosity of the Ivorian population was half that of the Italians. The lower observed heterozygosity and deviation from Hardy-Weinberg equilibrium could be the result of microevolutionary trends, such as genetic drift and/or inbreeding, acting on the relatively small and isolated population sampled for this study, although some sort of selective pressures acting against the shorter alleles cannot be excluded. This evidence, in association with the reduced polymorphism shown by the DAT1 VNTR compared to other VNTRs, seems to indicate that the DAT1 locus may be under some selective pressure.