We examined how BMI, BMI trajectories, and BMI fluctuation around these trajectories in adolescence were correlated with BMI trajectories and BMI fluctuation in early adulthood, as well as the genetic basis of these associations. BMI data from Finnish twins (N = 1379, 48% males) were collected at ages 11.5, 14, 17.5, 24, and 37 years. BMI trajectories in adolescence (11.5–17.5 years) and early adulthood (17.5–37 years) were estimated using linear mixed-effect models. BMI fluctuation was calculated as the average squared differences between observed and expected BMI around these trajectories. Genetic twin models and a polygenic risk score for BMI (PRSBMI) were used to assess genetic contributions to BMI fluctuation and its associations with BMI and BMI trajectories. Adolescent BMI fluctuation was positively correlated with early adulthood BMI trajectories in females, while in males, adolescent BMI trajectories were positively associated with BMI fluctuation in early adulthood. Genetic factors affected BMI fluctuation in both adolescence and early adulthood when estimated using twin modelling and PRSBMI. Adolescent BMI was positively associated with early adulthood fluctuation in both sexes, with genetic factors playing a role (genetic correlations .08–.29). It was concluded that genetic factors play a significant role in BMI fluctuations in adolescence and early adulthood, with some overlap with the genetics of BMI.

Cladonia norvegica was originally described from Norway based on different morphological and chemical characters distinguishing the species from C. coniocraea. Shortly after its description, material containing red spots on the thallus was reported from different parts of the world, but the taxonomic status of this form remained unclear. In this study, we investigated the morphological, chemical and genetic differences between the spotless form of C. norvegica and the red-spotted material. Phylogenetic analyses of mycobiont DNA (ITS rDNA, mtSSU, EF-1α) revealed that red-spotted specimens form a well-supported monophyletic clade, distinct from the spotless form of C. norvegica. We therefore describe red-spotted material as a new species, C. rubrotincta, with the type from Norway and we genetically and morphologically confirm occurrences from Austria, Czechia, Estonia, Great Britain and western Canada. The identity of the red pigment was confirmed to be a rhodocladonic acid by HPLC and LC-HRMS. Specimens with red spots exhibit consistently smaller and more irregularly shaped podetia. Additionally, our analysis of photobionts indicated that both species share a similar pool of Asterochloris symbionts. This study underscores the importance of integrating molecular, chemical, and morphological data in lichen taxonomy and provides insights into the distribution and ecological preferences of C. rubrotincta and C. norvegica.