BACKGROUND: Processes shaping the formation of the present-day population structure in highly urbanized Northern Europe are still poorly understood. Gaps remain in our understanding of when and how currently observable regional differences emerged and what impact city growth, migration, and disease pandemics during and after the Middle Ages had on these processes. RESULTS: We perform low-coverage sequencing of the genomes of 338 individuals spanning the eighth to the eighteenth centuries in the city of Sint-Truiden in Flanders, in the northern part of Belgium. The early/high medieval Sint-Truiden population was more heterogeneous, having received migrants from Scotland or Ireland, and displayed less genetic relatedness than observed today between individuals in present-day Flanders. We find differences in gene variants associated with high vitamin D blood levels between individuals with Gaulish or Germanic ancestry. Although we find evidence of a Yersinia pestis infection in 5 of the 58 late medieval burials, we were unable to detect a major population-scale impact of the second plague pandemic on genetic diversity or on the elevated differentiation of immunity genes. CONCLUSIONS: This study reveals that the genetic homogenization process in a medieval city population in the Low Countries was protracted for centuries. Over time, the Sint-Truiden population became more similar to the current population of the surrounding Limburg province, likely as a result of reduced long-distance migration after the high medieval period, and the continuous process of local admixture of Germanic and Gaulish ancestries which formed the genetic cline observable today in the Low Countries.

• Klíčová slova
• Flanders, Low countries, Medieval, Migration, Palaeo-genomics, Plague, Urbanization,
• MeSH
• dějiny středověku MeSH
• genetická variace MeSH
• genom lidský MeSH
• genomika MeSH
• lidé MeSH
• mor epidemiologie   dějiny   genetika   MeSH
• populační genetika MeSH
• urbanizace * dějiny   MeSH
• Check Tag
• dějiny středověku MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• historické články MeSH
• Geografické názvy
• Belgie MeSH

The confirmed number of SARS-CoV-2 infections up to 18 October 2022 is 626 million worldwide, but information about factors affecting the probability of infection or a severe course of COVID-19 remains insufficient and often speculative. Only a small number of factors have been rigorously examined, mostly by retrospective or cross-sectional studies. We ran a preregistered study on 5164 Internet users who shared information with us about their exposure to 105 risk factors and reported being COVID-19 negative before the beginning of the fourth wave of COVID-19 in the Czech Republic. After the fourth wave, in which 709 (13.7%) of participants were infected, we used a partial Kendall test controlled for sex, age, and urbanization to compare the risk of infection and a severe course of the disease in subjects who initially did and did not report exposure to particular risk factors. After the correction for multiple tests, we identified 13 factors - including male sex, lower age, blood group B, and larger household size - that increased the risk of infection and 16 factors - including mask-wearing, borreliosis in the past, use of vitamin D supplements, or rooibos drinking - that decreased it. We also identified 23 factors that increased the risk of a severe course of COVID-19 and 12 factors that decreased the risk. This preregistered longitudinal study is of explorative nature. Therefore, although the observed effects were strong and remained highly significant even after correction for multiple tests, it will be necessary to confirm their existence in future independent studies.

• Klíčová slova
• Borelia, COPD, Rh factor, SARS-CoV-2, autoimmunity, blood goups, cats, course, dogs, epidemiology, immunodeficiency, masks, risk factors, rooibos, tobacco smoking, use of sauna, vitamin D,
• Publikační typ
• časopisecké články MeSH

Women with red hair color, i.e., 1-9% of female Europeans, tend to be the subject of various stereotypes about their sexually liberated behavior. The aim of the present case-control study was to explore whether a connection between red hair color and sexual behavior really exists using data from 110 women (34% redheaded) and 93 men (22% redheaded). Redheadedness in women, correlated with various traits related to sexual life, namely with higher sexual desire as measured by Revised Sociosexual Orientation Inventory, with higher sexual activity and more sexual partners of the preferred gender over the past year, earlier initiation of sexual life, and higher sexual submissiveness. Structural equation modelling, however, showed that sexual desire of redheaded women mediated neither their higher sexual activity nor their higher number of sexual partners. These results indirectly indicate that the apparently more liberated sexual behavior in redheaded women could be the consequence of potential mates' frequent attempts to have sex with them. Our results contradicted the three other tested models, specifically the models based on the assumption of different physiology, faster life history strategy, and altered self-perception of redheaded women induced by stereotypes about them. Naturally, the present study cannot say anything about the validity of other potential models that were not subjects of testing.

• Klíčová slova
• mate selection, redheadedness, sexual activity, sexual behavior, sexual desire, sexual submissiveness, stereotypes,
• Publikační typ
• časopisecké články MeSH