Biology subjects

Vrtilek, M.

Publications and source records attributed to Vrtilek, M..

6 recordsLinked to original sources

bioRxiv2026

DNA methylation profile is not inherited in offspring of a short-lived annual fish

Parental ageing can influence offspring through non-genetic mechanisms. The contribution of epigenetic inheritance parental effects still remains poorly understood. DNA methylation is a widespread regulator of gene expression that changes during development and ageing and can also act as a mediator of intergenerational effects. We tested whether age-related changes in parental DNA methylation are transmitted to offspring in the short-lived turquoise killifish (Nothobranchius furzeri, Cyprinodontiformes). Using reduced-representation sequencing, we quantified genome-wide DNA methylation and examined methylation dynamics at individual loci. The overall proportion of methylated CpG sites increased during early ageing but declined at later ages, revealing a non-linear trajectory with substantial among-individual variation. Despite these age-related changes, we found no evidence that parental methylation patterns were transmitted to offspring, either at the genome-wide level or at individual loci. Our findings indicate that although DNA methylation undergoes pronounced age-dependent remodelling in adult killifish, these changes are not detectably inherited by the next generation. We discuss these results in the context of epigenetic inheritance and ageing in vertebrate model systems.

evolutionary biology↗

bioRxiv2025

Fins as a reliable surrogate tissue for age-related changes of telomeres and DNA methylation in gonads of a short-lived fish

Senescence is a multifactorial and individualised process of age-related physiological decline. Cellular markers, such as telomere length and DNA methylation, can reveal subtle changes associated with chronological age or expected lifespan. In this study, we evaluated the utility of fin tissue as a surrogate for assessing telomere length and proportion of DNA methylation in the gonads of a small, short-lived laboratory fish, the turquoise killifish (Nothobranchius furzeri). We collected fin and gonadal tissues from both females and males at three different ages, and extracted DNA to measure telomere length via terminal restriction fragment (TRF) analysis and global DNA methylation levels using double-digest restriction-associated DNA sequencing (ddRADseq). Our results show a notable correspondence between telomere length and DNA methylation patterns in fin and gonadal tissues. These findings support the use of fin biopsies as a non-lethal method for assessing ageing biomarkers in the gonads of small freshwater fish.

molecular biology↗

bioRxiv2024

Macroevolutionary changes in gene expression response to an immune stimulus across the diversity of fishes

Our understanding of the vertebrate immune system is dominated by a few model organisms such as mice. This use of a few model systems is reasonable if major features of the immune systems evolve slowly and are conserved across most vertebrates, but may be problematic if there is substantial macroevolutionary change in immune responses. Here, we present a test of the macroevolutionary stability, across 15 species of jawed fishes, of the transcriptomic response to a standardized immune challenge. Intraperitoneal injection of an immune adjuvant (alum) induces a fibrosis response in nearly all jawed fishes, which in some species contributes to anti-helminth resistance. Despite this conserved phenotypic response, the underlying transcriptomic response is highly inconsistent across species. Although many gene orthogroups exhibit differential expression between saline versus alum-injected fish in at least one species, few orthogroups exhibit consistent differential expression across species. This result suggests that although the phenotypic response to alum (fibrosis) is highly conserved, the underlying gene regulatory architecture is very flexible and cannot readily be extrapolated from any one species to fishes (or vertebrates) more broadly. The vertebrate immune response is remarkably changeable over macroevolutionary time, requiring a diversity of model organisms to describe effectively.

evolutionary biology↗

bioRxiv2020

Environment and sex control lifespan and telomere length in wild-derived African killifish

Telomere length is correlated positively with longevity at the individual level, but negatively when compared across species. Here, we tested the association between lifespan and telomere length in African annual killifish. We analyzed telomere length in 18 Nothobranchius strains derived from diverse habitats and measured the laboratory lifespan of 14 strains of N. furzeri and N. kadleci. We found that males had shorter telomeres than females. The longest telomeres were recorded in strains derived from dry region where male lifespans were shortest. At the individual level, we detected a weak negative association between rapid juvenile growth and shorter telomeres in early adulthood. Overall, average telomere length was a good descriptor of telomere length distribution. However, within-individual telomere length spread was not related to any pattern. This substantial variation in telomere length between strains from different environments provides killifish as powerful tool to understand the evolutionarily adaptive value of telomere length.

evolutionary biology↗

bioRxiv2020

Egg size does not universally predict embryonic resources and hatchling size across annual killifish species

Egg size has a crucial impact on the reproductive success of a mother and the performance of her offspring. It is therefore reasonable to employ egg size as a proxy for egg content when studying variation in offspring performance. Here, we tested species differences in allometries of several egg content parameters with egg area. We measured individual eggs in five species of annual killifish (Cyprinodontiformes), a group of fish where egg banks permit population survival over dry season. Apart from comparing allometric scaling exponents, amounts and compositions of egg components across the different species, we assessed the explanatory power of egg area for egg wet and dry weight and for hatchling size. We found notable species-specific allometries between egg area and the other egg parameters (egg dry weight and water content, elemental composition and triglyceride content). Across species, egg area predicted egg wet weight with highest power. Within species, coefficients of determination were largest in Austrolebias elongatus, a large piscivorous species with large eggs. Our study shows that systematically using egg area as a proxy of egg content between different species can ignore relevant species-specific differences and mask within-species variability in egg content.

zoology↗

bioRxiv2020

The role of maternal effects on offspring performance in familiar and novel environments

Maternal effects are an important evolutionary force that may either facilitate adaptation to a new environment or buffer against unfavourable conditions. The degree of variation in traits expressed by siblings from different mothers is frequently sensitive to environmental conditions. This could generate a Maternal-by-Environment interaction (MxE) that could inflate estimates of Genotype-by-Environment effects (GxE). We aimed to test for environment-specific maternal effects (MxE) using a paternal full-sib/half-sib breeding design in the seed beetle Callosobruchus maculatus, where we split and reared offspring from the same mother on two different bean host types - original and novel. Our quantitative genetic analysis indicated that maternal effects were very small on both host types for all the measured life-history traits. There was also little evidence that maternal oviposition preference for a particular host type predicted her offsprings performance on that host. Further, additive genetic variance for most traits was relatively high on both hosts. While there was higher heritability for offspring reared in the novel host, there was no evidence for GxEs, and most cross-host genetic correlations were positive. This suggests that offspring from the same family ranked similarly for performance on both host types. Our results point to a genetic basis of host adaptation in the seed beetle, rather than maternal effects. Even so, we encourage researchers to test for potential MxEs because, due to a lack of testing, it remains unclear how often they arise.

evolutionary biology↗