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- Darki, Fahimeh, et al.
(author)
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Human ROBO1 regulates white matter structure in corpus callosum.
- 2017
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In: Brain Structure and Function. - : Springer Science and Business Media LLC. - 1863-2653 .- 1863-2661. ; 222:2, s. 707-716
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Journal article (peer-reviewed)abstract
- The axon guidance receptor, Robo1, controls the pathfinding of callosal axons in mice. To determine whether the orthologous ROBO1 gene is involved in callosal development also in humans, we studied polymorphisms in the ROBO1 gene and variation in the white matter structure in the corpus callosum using both structural magnetic resonance imaging and diffusion tensor magnetic resonance imaging. We found that five polymorphisms in the regulatory region of ROBO1 were associated with white matter density in the posterior part of the corpus callosum pathways. One of the polymorphisms, rs7631357, was also significantly associated with the probability of connections to the parietal cortical regions. Our results demonstrate that human ROBO1 may be involved in the regulation of the structure and connectivity of posterior part of corpus callosum.
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2. |
- Lappalainen, Tuuli, et al.
(author)
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Genomic landscape of positive natural selection in Northern European populations.
- 2010
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In: European Journal of Human Genetics. - : Nature Publishing Group. - 1018-4813 .- 1476-5438. ; 18:4, s. 471-478
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Journal article (peer-reviewed)abstract
- Analyzing genetic variation of human populations for detecting loci that have been affected by positive natural selection is important for understanding adaptive history and phenotypic variation in humans. In this study, we analyzed recent positive selection in Northern Europe from genome-wide data sets of 250 000 and 500 000 single-nucleotide polymorphisms (SNPs) in a total of 999 individuals from Great Britain, Northern Germany, Eastern and Western Finland, and Sweden. Coalescent simulations were used for demonstrating that the integrated haplotype score (iHS) and long-range haplotype (LRH) statistics have sufficient power in genome-wide data sets of different sample sizes and SNP densities. Furthermore, the behavior of the F(ST) statistic in closely related populations was characterized by allele frequency simulations. In the analysis of the North European data set, 60 regions in the genome showed strong signs of recent positive selection. Out of these, 21 regions have not been discovered in previous scans, and many contain genes with interesting functions (eg, RAB38, INFG, NOS1AP, and APOE). In the putatively selected regions, we observed a statistically significant overrepresentation of genetic association with complex disease, which emphasizes the importance of the analysis of positive selection in understanding the evolution of human disease. Altogether, this study demonstrates the potential of genome-wide data sets to discover loci that lie behind evolutionary adaptation in different human populations.
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3. |
- Salmela, Elina, et al.
(author)
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Genome-wide analysis of single nucleotide polymorphisms uncovers population structure in Northern Europe
- 2008
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In: PLOS ONE. - San Fransisco : Public library of science. - 1932-6203. ; 3:10
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Journal article (peer-reviewed)abstract
- Background: Genome-wide data provide a powerful tool for inferring patterns of genetic variation and structure of human populations.Principal Findings: In this study, we analysed almost 250,000 SNPs from a total of 945 samples from Eastern and Western Finland, Sweden, Northern Germany and Great Britain complemented with HapMap data. Small but statistically significant differences were observed between the European populations (F(ST) = 0.0040, p < 10(-4)), also between Eastern and Western Finland (F(ST) = 0.0032, p < 10(-3)). The latter indicated the existence of a relatively strong autosomal substructure within the country, similar to that observed earlier with smaller numbers of markers. The Germans and British were less differentiated than the Swedes, Western Finns and especially the Eastern Finns who also showed other signs of genetic drift. This is likely caused by the later founding of the northern populations, together with subsequent founder and bottleneck effects, and a smaller population size. Furthermore, our data suggest a small eastern contribution among the Finns, consistent with the historical and linguistic background of the population.Significance: Our results warn against a priori assumptions of homogeneity among Finns and other seemingly isolated populations. Thus, in association studies in such populations, additional caution for population structure may be necessary. Our results illustrate that population history is often important for patterns of genetic variation, and that the analysis of hundreds of thousands of SNPs provides high resolution also for population genetics.
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4. |
- Salmela, Elina, et al.
(author)
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Swedish population substructure revealed by genome-wide single nucleotide polymorphism data
- 2011
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 6:2, s. e16747-
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Journal article (peer-reviewed)abstract
- The use of genome-wide single nucleotide polymorphism (SNP) data has recently proven useful in the study of human population structure. We have studied the internal genetic structure of the Swedish population using more than 350,000 SNPs from 1525 Swedes from all over the country genotyped on the Illumina HumanHap550 array. We have also compared them to 3212 worldwide reference samples, including Finns, northern Germans, British and Russians, based on the more than 29,000 SNPs that overlap between the Illumina and Affymetrix 250K Sty arrays. The Swedes--especially southern Swedes--were genetically close to the Germans and British, while their genetic distance to Finns was substantially longer. The overall structure within Sweden appeared clinal, and the substructure in the southern and middle parts was subtle. In contrast, the northern part of Sweden, Norrland, exhibited pronounced genetic differences both within the area and relative to the rest of the country. These distinctive genetic features of Norrland probably result mainly from isolation by distance and genetic drift caused by low population density. The internal structure within Sweden (F(ST) = 0.0005 between provinces) was stronger than that in many Central European populations, although smaller than what has been observed for instance in Finland; importantly, it is of the magnitude that may hamper association studies with a moderate number of markers if cases and controls are not properly matched geographically. Overall, our results underline the potential of genome-wide data in analyzing substructure in populations that might otherwise appear relatively homogeneous, such as the Swedes.
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5. |
- Salmela, Jatta, et al.
(author)
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Associations of childhood and adult socioeconomic circumstances with recommended food habits among young and midlife Finnish employees
- 2022
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In: BMC Nutrition. - : Springer Nature. - 2055-0928. ; 8
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Journal article (peer-reviewed)abstract
- Background: Disadvantaged socioeconomic circumstances are associated with certain unhealthy food habits such as inadequate consumption of fruit and vegetables. This study examined whether multiple socioeconomic measures are consistently associated with a variety of food habits.Methods: We examined associations of 2 childhood and 6 adult socioeconomic measures with 8 recommended food habits among 19-39-year-old employees of the City of Helsinki, Finland. The data were collected in 2017 via online and mailed surveys. Our sample consisted of 4621 employees (80% women). The analyses included adjusted binary logistic regression models.Results: More advantaged socioeconomic circumstances were positively associated with the recommended consumption of vegetables, fruit or berries, dark bread, skimmed milk products, fish, and cooking oil, but not consistently with red or processed meat and fat spread. All socioeconomic measures were positively associated with having several (6-8) recommended food habits after gender and age adjustments. The strongest associations were found for participant's education, occupational class, and current financial difficulties. These associations remained after adjustments of childhood and adult socioeconomic measures, although especially participant's education attenuated the associations for occupational class.Conclusions: The consistent associations between multiple childhood and adult socioeconomic measures and food habits found among employees highlight the need for improving food habits among people with disadvantaged socioeconomic circumstances in particular. Financial barriers together with social aspects of adhering to healthy diets should be considered in future dietary interventions and policy actions.
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