Jukka Jokela


Last Name

Jokela

First Name

Jukka

ORCID

0000-0002-1731-727X

Organisational unit

03705 - Jokela, Jukka / Jokela, Jukka

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Publications 1 - 10 of 116
  • Among- and within-population variation in outcrossing rate of a mixed-mating freshwater snail
    Item type: Journal Article
    Jokela, Jukka; Wiehn, J.; Kopp, Kirstin (2006)
    Heredity
  • On biological evolution and environmental solutions
    Item type: Journal Article
    Matthews, Blake; Jokela, Jukka; Narwani, Anita; et al. (2020)
    Science of The Total Environment
    Drawing insights from multiple disciplines is essential for finding integrative solutions that are required to tackle complex environmental problems. Human activities are causing unprecedented influence on global ecosystems, culminating in the loss of species and fundamental changes in the selective environments of organisms across the tree of life. Our collective understanding about biological evolution can help identify and mitigate many of the environmental problems in the Anthropocene. To this end, we propose a stronger integration of environmental sciences with evolutionary biology. © 2020 Elsevier B.V.
  • Phylogeography and cryptic species structure of a locally adapted parasite in New Zealand
    Item type: Journal Article
    Feijen, Frida; Zajac, Natalia; Vorburger, Christoph; et al. (2022)
    Molecular Ecology
    The phylogeographic patterns of many taxa on New Zealand's South Island are characterized by disjunct distributions that have been attributed to Pleistocene climatic cycles and the formation of the Southern Alps. Pleistocene glaciation has been implicated in shaping the contemporary genetic differentiation between populations of the aquatic snail Potamopyrgus antipodarum. We investigated whether similar phylogeographic patterns exist for the snail's locally adapted trematode parasite, Atriophallophorus winterbourni. We found evidence for a barrier to gene-flow in sympatry between cryptic, but ecologically divergent species. When focusing on the most common of these species, disjunct geographic distributions are found for mitochondrial lineages that diverged during the Pleistocene. The boundary between these distributions is found in the central part of the South Island and is reinforced by low cross-alpine migration. Further support for a vicariant origin of the phylogeographic pattern was found when assessing nuclear multilocus SNP data. Nuclear and mitochondrial population differentiation was concordant in pattern, except for populations in a potential secondary contact zone. Additionally, we found larger than expected differentiation between nuclear- and mitochondrial-based empirical Bayes FST estimates (global FST: 0.02 vs. 0.39 for nuclear and mitochondrial data, respectively). Population subdivision is theoretically expected to be stronger for mitochondrial genomes due to a smaller effective population size, but the strong difference here, together with mitonuclear discordance in a putative contact zone, is potentially indicative of divergent gene flow of nuclear and mitochondrial genomes.
  • Totivirus-satellite coinfection prevalence and host genotype associations in wild Saccharomyces cerevisiae
    Item type: Journal Article
    Travers-Cook, Tommy J.; Knight, Sarah J.; Lee, Soon; et al. (2025)
    FEMS Microbiology Ecology
    Saccharomyces cerevisiae is occasionally infected by dsRNA totiviruses and their toxin-encoding dsRNA satellite nucleic acids. The autonomous totivirus and its satellite can coexist but with an asymmetric dependence of the satellite on the totivirus for replication and maintenance inside the host cell. Satellites provide their yeast hosts with inhibitory toxins and the necessary self-immunity; loss of the satellite equates to loss of toxin immunity. Because these viral elements lack known extracellular stages, and sex is suspected to be rare, they are assumed to be transmitted vertically, implying that infection states should correlate with host genotypes. However, totivirus-satellite coinfections are rarely examined in natural populations, leaving their associations with host genotypes poorly understood. We screened a multiyear, vineyard-associated population of S. cerevisiae isolates from New Zealand to examine the stability of host-virus associations over time, both within and across genotypes. Over half of the wild isolates harbored infections (55%), but less than half of these (37% of infected) had toxin-encoding satellites. Genotypes that persisted across years typically maintained consistent infection states. However, we also observed stepwise transitions from coinfection through infection to an infection-free state, as well as acquisition of totiviruses and satellites. Genotypes clustered strongly by infection state, and population heterozygosity was significantly lower than expected, supporting vertical transmission while suggesting that outcrossing is not responsible for the acquisition of higher infection states. Despite occasional intragenotypic transitions, genotype clustering by infection state remained intact, suggesting that such transitions are transient and that host genotypes may have optimal infection states with regard to totiviruses and their satellites.
  • Comparing direct and indirect selfing rate estimates: when are population-structure estimates reliable?
    Item type: Journal Article
    Bürkli, Anja; Sieber, N.; Seppälä, Katri; et al. (2017)
    Heredity
  • Host and parasite intervality in differentially human-modified habitats
    Item type: Journal Article
    Llopis-Belenguer, Cristina; Feijen, Frida; Morand, Serge; et al. (2024)
    Oikos
    Host-parasite interactions are influenced by present and past eco-evolutionary interactions and the local environment. An ecological community defines the potential host range of each parasite and the potential parasite diversity of each host species. Past and present processes translate potential to realised interaction niches of parasite and host species. Host-parasite interactions are antagonistic, which may slow the saturation of their interaction niches. Intervality, a property of bipartite networks, measures saturation of interaction niches. Intervality of a community increases as the interaction niches of species of one guild (e.g. hosts) become saturated for their interactions with another guild (e.g. parasites). Characteristics driving intervality in host and parasite communities are largely unknown, as well as the effect of environmental change on intervality of these communities. In our study, we assess if the characteristics 'phylogenetic relatedness' and 'overlap in ecological interactions' explain intervality of rodent host-helminth parasite communities. In addition, we contrast intervality of these communities from habitats that differ in their history of human-driven modification. We performed the analyses for the interaction niches of both parasites and hosts, independently. Our results indicated that host and parasite communities were non-interval or significantly less interval than expected by chance. Phylogenetic relatedness and overlap in ecological interactions did not explain the maximum values of intervality. We speculate that antagonistic coevolution in host-parasite communities may hinder communities to reach saturation, which would explain why it is difficult to find the characteristics that explain intervality of a community. Interestingly, intervality of the interaction niche of parasites (host range) increased with habitat modification (i.e. saturation increased), whereas intervality of the interaction niche of hosts (parasite diversity) decreased as habitat modification increased. These opposite trends suggest that interaction niches of parasites and hosts respond differently to habitat modification.
  • Estimating species distribution and abundance in river networks using environmental DNA
    Item type: Journal Article
    Carraro, Luca; Hartikainen, Hanna; Jokela, Jukka; et al. (2018)
    Proceedings of the National Academy of Sciences of the United States of America
    All organisms leave traces of DNA in their environment. This environmental DNA (eDNA) is often used to track occurrence patterns of target species. Applications are especially promising in rivers, where eDNA can integrate information about populations upstream. The dispersion of eDNA in rivers is modulated by complex processes of transport and decay through the dendritic river network, and we currently lack a method to extract quantitative information about the location and density of populations contributing to the eDNA signal. Here, we present a general framework to reconstruct the upstream distribution and abundance of a target species across a river network, based on observed eDNA concentrations and hydro-geomorphological features of the network. The model captures well the catchment-wide spatial biomass distribution of two target species: a sessile invertebrate (the bryozoan Fredericella sultana) and its parasite (the myxozoan Tetracapsuloides bryosalmonae). Our method is designed to easily integrate general biological and hydrological data and to enable spatially explicit estimates of the distribution of sessile and mobile species in fluvial ecosystems based on eDNA sampling.
  • Interactions among bacterial strains and fluke genotypes shape virulence of co-infection
    Item type: Journal Article
    Louhi, Katja-Riikka; Sundberg, Lotta-Riina; Jokela, Jukka; et al. (2015)
    Proceedings of the Royal Society B: Biological Sciences
  • Effects of growth factors and water source on laboratory cultures of a northern Asellus aquaticus (Isopoda) population
    Item type: Journal Article
    Hasu, Tiina; Jokela, Jukka; Valtonen, E. Tellervo (2008)
    Aquatic Ecology
Publications 1 - 10 of 116