A genomic Neolithic time transect of hunter-farmer admixture in central Poland.

Ancient DNA genome-wide analyses of Neolithic individuals from central and southern Europe indicate an overall population turnover pattern in which migrating farmers from Anatolia and the Near East largely replaced autochthonous Mesolithic hunter-gatherers. However, the genetic history of the Neolithic transition in areas lying north of the European Neolithic core region involved different levels of admixture with hunter-gatherers. Here we analyse genome-wide data of 17 individuals spanning from the Middle Neolithic to the Early Bronze Age (4300-1900 BCE) in order to assess the Neolithic transition in north-central Poland, and the local impacts of hunter-farmer contacts and Late Neolithic steppe migrations. We evaluate the influence of these on local populations and assess if and how they change through time, reporting evidence of recurrent hunter-farmer admixture over three millennia, and the co-existence of unadmixed hunter-gatherers as late as 4300 BCE. During the Late Neolithic we report the appearance of steppe ancestry, but on a lesser scale than previously described for other central European regions, with evidence of stronger affinities to hunter-gatherers than to steppe pastoralists. These results help understand the Neolithic palaeogenomics of another central European area, Kuyavia, and highlight the complexity of population interactions during those times.

Association of five SNPs with human hair colour in the Polish population.

Twenty-two variants (single nucleotide polymorphisms - SNPs) of the genes involved in hair pigmentation (OCA2, HERC2, MC1R, SLC24A5, SLC45A2, TPCN2, TYR, TYRP1) were genotyped in a group of 186 Polish participants, representing a range of hair colours (45 red, 64 blond, 77 dark). A genotype-phenotype association analysis was performed. Using z-statistics we identified three variants highly associated with different hair colour categories (rs12913832:A>G in HERC2, rs1805007:T>C and rs1805008:C>T in MC1R). Two variants: rs1800401:C>T in OCA2 and rs16891982:C>G in SLC45A2 showed a high probability of a relation with hair colour, although that probability did not exceed the threshold of statistical significance after applying the Bonferroni correction. We created and validated mathematical logistic regression models in order to test the usefulness of the sets of polymorphisms for hair colour prediction in the Polish population. We subjected four models to stratified cross-validation. The first model consisted of three polymorphisms that proved to be important in the associative analysis. The second model included, apart from the mentioned polymorphisms, additionally rs16891982:C>G in SLC45A. The third model included, apart from the variants relevant in the associating analysis, rs1800401:C>T in OCA. The fourth model consisted of the set of polymorphisms from the first model supplemented with rs16891982:C>G in SLC45A and rs1800401:C>T in OCA. The validation of our models has shown that the inclusion of rs16891982:C>G in SLC45A and rs1800401:C>T in OCA increases the prediction of red hair in comparison with the algorithm including only rs12913832:A>G in HERC2, rs1805007:T>C and rs1805008:C>T in MC1R. The model consisting of all the five above-mentioned genetic variants has shown good prediction accuracies, expressed by the area under the curve (AUC) of the receiver operating characteristics: 0.84 for the red-haired, 0.82 for the dark-haired and 0.71 for the blond-haired. A genotype-phenotype association analysis brought results similar to those in other studies and confirmed the role of rs16891982:C>G, rs12913832:A>G, rs1805007:T>C and rs1805008:C>T in hair colour determination in the Polish population. Our study demonstrated for the first time the possibility of a share of the rs1800401:C>T SNP in the OCA2 gene in hair colour determination. Including this single nucleotide polymorphism in the actual hair colour predicting models would improve their predictive accuracy.

Parental smoking during pregnancy shortens offspring's legs.

One of the most severe detrimental environmental factors acting during pregnancy is foetal smoke exposure. The aim of this study was to assess the effect of maternal, paternal and parental smoking during pregnancy on relative leg length in 7- to 10-year-old children. The research conducted in the years 2001-2002 included 978 term-born children, 348 boys and 630 girls, at the age of 7-10 years. Information concerning the birth weight of a child was obtained from the health records of the women. Information about the mother's and the father's smoking habits during pregnancy and about the mothers' education level was obtained from a questionnaire. The influence of parental smoking on relative leg length, controlled for age, sex, birth weight and the mother's education, as a proxy measure of socioeconomic status, and controlled for an interaction between sex and birth weight, was assessed by an analysis of covariance, where relative leg length was the dependent variable, smoking and sex were the independent variables, and birth weight as well as the mother's education were the covariates. Three separate analyses were run for the three models of smoking habits during pregnancy: the mother's smoking, the father's smoking and both parents' smoking. Only both parents' smoking showed a significant effect on relative leg length of offspring. It is probable that foetal hypoxia caused by carbon monoxide contained in smoke decelerated the growth of the long bones of foetuses.

Prenatal factors associated with the neonatal line thickness in human deciduous incisors.

The neonatal line (NNL) is used to distinguish developmental events observed in enamel which occurred before and after birth. However, there are few studies reporting relationship between the characteristics of the NNL and factors affecting prenatal conditions. The aim of the study was to determine prenatal factors that may influence the NNL thickness in human deciduous teeth. The material consisted of longitudinal ground sections of 60 modern human deciduous incisors obtained from full-term healthy children with reported birth histories and prenatal factors. All teeth were sectioned in the labio-lingual plane using diamond blade (Buechler IsoMet 1000). Final specimens were observed using scanning electron microscopy at magnifications 320×. For each tooth, linear measurements of the NNL thickness were taken on its labial surface at the three levels from the cemento-enamel junction. The difference in the neonatal line thickness between tooth types and between males and females was statistically significant. A multiple regression analyses confirmed influence of two variables on the NNL thickness standardised on tooth type and the children's sex (z-score values). These variables are the taking of an antispasmodic medicine by the mother during pregnancy and the season of the child's birth. These two variables together explain nearly 17% of the variability of the NNL. Children of mothers taking a spasmolytic medicine during pregnancy were characterised by a thinner NNL compared with children whose mothers did not take such medication. Children born in summer and spring had a thinner NNL than children born in winter. These results indicate that the prenatal environment significantly contributes to the thickness of the NNL influencing the pace of reaching the post-delivery homeostasis by the newborn's organism.

Adolescent growth: genes, hormones and the peer group. Proceedings of the 20th Aschauer Soiree, held at Glücksburg castle, Germany, 15th to 17th November 2013.

The association between poverty, malnutrition, illness and poor socioeconomic conditions on the one side, and poor growth and short adult stature on the other side, is well recognized. Yet, the simple assumption by implication that poor growth and short stature result from poor living conditions, should be questioned. Recent evidence on the impact of the social network on adolescent growth and adult height further challenges the traditional concept of growth being a mirror of health. Twenty-nine scientists met at Glücksburg castle, Northern Germany, November 15th - 17th 2013, to discuss genetic, endocrine, mathematical and psychological aspects and related issues, of child and adolescent growth and final height.

The effect of the season of birth and of selected maternal factors on linear enamel thickness in modern human deciduous incisors.

OBJECTIVE: Development of human tooth enamel is a part of a foetus's development; its correctness is the outcome of genetic and maternal factors shaping its prenatal environment. Many authors reported that individuals born in different seasons experience different early developmental conditions during pregnancy. In this study, we investigated the effects of season of birth and selected maternal factors on enamel thickness of deciduous incisors. DESIGN: Dental sample comprises 60 deciduous incisors. The parents who handed over their children's teeth for research fill in questionnaires containing questions about the course of pregnancy. All teeth were sectioned in the labio-linqual plane using diamond blade (Buechler IsoMet 1000). The final specimens were observed by way of scanning electron microscopy at magnifications 80× and 320×. The thickness of total enamel (TE), prenatally (PE) and postnatally (PSE) formed enamel was measured. RESULTS: Children born in summer and in spring (whose first and second foetal life fall on autumn and winter) have the thinnest enamel. Season of birth, number of children in family, diseases and spasmolytic medicines using by mother during pregnancy explained almost 13% of the variability of TE. Regression analysis proved a significant influence of the season of birth and selected maternal factors on the PE thickness - these factors explained over 17% of its variability. Neither of analysed variables had influenced PSE. CONCLUSIONS: Our findings suggests that the thickness of enamel of deciduous incisors depends on the season of birth and some maternal factors. The differences were observed only in the prenatally formed enamel.

Is increased constitutive skin and hair pigmentation an early sign of puberty?

The paper analyzes data concerning the constitutive skin and hair pigmentation of 7-10-year-old Polish children to examine whether the hormonal activity of the gonads, which increases in this period, causes changes in pigmentation levels that may be considered an early sign of puberty. The study involved 289 children (151 girls and 138 boys). Skin pigmentation was examined on the medial side of the arm, while hair pigmentation on strands of hair close to the scalp in the occipital area. Additionally, body height (B-v) was measured and compared with population norms. On this basis, it was ascertained that the studied sample was representative of the population from which it was taken and that it represented the prepubertal and early pubertal stages of ontogeny (prior to the pubertal growth spurt or the first menstruation in the studied girls). It was found that in 7-10-year-old Polish children there is a statistically significant (p=0.001) increase in skin and hair pigmentation levels, while the degree of pigmentation of both structures at this stage of ontogeny is sexually dimorphic: girls are characterized by stronger pigmentation than boys. At the age of 10 years, the dimorphic differences in skin pigmentation intensify due to a rapid rise in pigmentation in girls. This change may be deemed an early morphological sign of puberty, as it precedes the pubertal growth spurt and menarche. This fast increase in skin pigmentation is not paralleled by an analogous change in hair pigmentation.

Frequency of under- and overweight among children and adolescents during the economic transition in Poland.

The aim of this study is to examine the prevalence of underweight, overweight and obesity, using International Obesity Task Force (IOTF) criteria, in four cohorts of children and adolescents living in Poland in different economic eras: communist economy (1977/1978), crisis of the 1980s (1987/1988), political and economic transformation (1992/1994) and the free market economy (2002/2004). Analysis was conducted on a database including 10,934 records for children of the age 7-18 years. In Poland, in the last 26 years of economic and political transformations, the epidemic of obesity was not noticed but the growing incidence of children and adolescents with body mass deficit was observed (p<0.0001) (20.2% of girls in 2002/2004 vs. 11.0% in 1977/1978 and 12.1% of boys in 2002/2004 vs. 7.2% in 1977/1978). Lower parental education and a higher number of children in a family resulted in a higher prevalence of underweight (odds ratio [OR] fluctuated from 1.26 to 1.63). The social effects of the political transformation in Poland significantly affected families with low socio-economic status (SES), and especially more eco-sensitive boys. This result is opposite to the trends observed in Western countries and makes an important contribution to the current knowledge of the course of further changes in weight-to-height ratio at a global scale.

Impact of economic conditions on the secondary sex ratio in a post-communist economy.

According to the Trivers-Willard hypothesis the secondary sex ratio (SSR, the ratio of male to female newborns [M/F]) should be positively related to the parents' living conditions. This also means that if in some population parents experience environmental (e.g. economic) stress, the SSR should be relatively low. If this holds true, the fluctuations in the SSR of offspring could be one of the ways the human population reacts to environmental (and also socio-economic) changes. Although confirmed for many human populations, such a relationship was not observed in the populations living in the communist-era planned-economy countries until recently. We test the hypothesis that economic stress in Poland after the communist era is also related to the SSR decrease. Using quarterly data from the years 1995-2007 about the total number of live male (M) and female (F) newborns born in central Poland (sample size=310,532), we calculated the time series of the SSR. The quarterly economic conditions of the studied population within the period under consideration constituted the time series of the percentage change in private consumption at constant prices of the year 2000. The relationship between the SSR and the economic conditions in the analyzed 47 quarters of the year was tested with the use of the ARMA models. We have found that four quarters (one year) after the occurrence of economic stress there was a decline in the SSR. This result is consistent with the Trivers-Willard hypothesis at the population level in a modern free-trade economy of a post-communist country.

Sex diagnosis of subadult specimens from Medieval Polish archaeological sites: metric analysis of deciduous dentition.

The subject of this work is the characterisation of the metric features of deciduous dentition in a Medieval population of central Poland with the use of the jackknife technique leave one out (LOO)-supporting multivariate methods, which are important for deriving discrimination equations that would result in sex determination of children's skeletal remains. The sex of the individuals was assessed through analysis of sex-specific DNA sequences (AMELY/AMELX, SRY and alpha satellite sequences). Discriminant analysis concerned only teeth of those individuals whose sex was confirmed by the primary structure of three DNA sequences. The deciduous tooth diameters of males were found to be significantly larger than those of females in four respects: MD diameter of the maxillary second molar, MD and BL diameters of the mandibular first molar and BL diameter of the mandibular second molar. A two-group discriminant analysis considered all those measurements as independent variables. A multiple regression procedure produced a linear equation predicting the sex of children's skeletons with a significant probability amounting to approximately 78%. The accuracy of the sex assessment of an individual, using dental measurements, was established at 69% in deciduous male and 88% in deciduous female teeth.