Sophie von der Heyden
Stellenbosch University, Botany and Zoology, Faculty Member
ABSTRACT: To enhance our current understanding of the evolution of intertidal marine species, we investigated the phylogeographic population structure of the Cape sea urchin Parechinus angulosus using cytochrome c oxidase subunit I (COI)... more
ABSTRACT: To enhance our current understanding of the evolution of intertidal marine species, we investigated the phylogeographic population structure of the Cape sea urchin Parechinus angulosus using cytochrome c oxidase subunit I (COI) mitochondrial and receptor for egg jelly protein 9 (SpREJ9) nuclear DNA (nDNA) sequence data.
A single or double amino acid insertion at the monomer–monomer junction of the universal eukaryotic protein polyubiquitin is unique to Cercozoa and Foraminifera, closely related 'core'phyla in the protozoan infrakingdom Rhizaria. We... more
A single or double amino acid insertion at the monomer–monomer junction of the universal eukaryotic protein polyubiquitin is unique to Cercozoa and Foraminifera, closely related 'core'phyla in the protozoan infrakingdom Rhizaria. We screened 11 other candidate rhizarians for this insertion: Radiozoa (polycystine and acantharean radiolaria), a 'microheliozoan', and Apusozoa; all lack it, supporting suggestions that Foraminifera are more closely related to Cercozoa than either is to other eukaryotes.
Abstract von der Heyden, S., Barendse, J., Seebregts, AJ, and Matthee, CA 2010. Misleading the masses: detection of mislabelled and substituted frozen fish products in South Africa.–ICES Journal of Marine Science, 67: 176–185.... more
Abstract von der Heyden, S., Barendse, J., Seebregts, AJ, and Matthee, CA 2010. Misleading the masses: detection of mislabelled and substituted frozen fish products in South Africa.–ICES Journal of Marine Science, 67: 176–185. Mislabelling poses a threat to the sustainability of seafood supply chains and, when frequent, can significantly affect conservation efforts.
Background Oceanography and life-history characteristics are known to influence the genetic structure of marine species, however the relative role that these factors play in shaping phylogeographic patterns remains unresolved.
Abstract Biogeographic boundaries are the meeting zone of broadly distributed faunas, or the actual cause of a faunal break. In the latter case, closely related sister species should be found across such a boundary. To achieve such a... more
Abstract Biogeographic boundaries are the meeting zone of broadly distributed faunas, or the actual cause of a faunal break. In the latter case, closely related sister species should be found across such a boundary. To achieve such a situation, preliminary stages are expected, where phylogeographic breaks followed by genetic cryptic speciation would be observed. Biogeographic boundaries, in the Cape Point/Cape Agulhas region of southern Africa, offer an ideal system to test such predictions.
The southern African marine realm is located at the transition zone between the Atlantic and Indo-Pacific biomes. Its biodiversity is particularly rich and comprises faunal and floral elements from the two major oceanic regions, as well... more
The southern African marine realm is located at the transition zone between the Atlantic and Indo-Pacific biomes. Its biodiversity is particularly rich and comprises faunal and floral elements from the two major oceanic regions, as well as a large number of endemics.
Abstract Resolution of the phylogenetic relationships among the major eukaryotic groups is one of the most important problems in evolutionary biology that is still only partially solved. This task was initially addressed using a single... more
Abstract Resolution of the phylogenetic relationships among the major eukaryotic groups is one of the most important problems in evolutionary biology that is still only partially solved. This task was initially addressed using a single marker, the small-subunit ribosomal DNA (SSU rDNA), although in recent years it has been shown that it does not contain enough phylogenetic information to robustly resolve global eukaryotic phylogeny.
Sand-smelts are small fishes inhabiting inshore, brackish and freshwater environments and with a distribution in the eastern Atlantic and Mediterranean Sea, extending south into the Indian Ocean. Here, we present a broad phylogenetic... more
Sand-smelts are small fishes inhabiting inshore, brackish and freshwater environments and with a distribution in the eastern Atlantic and Mediterranean Sea, extending south into the Indian Ocean. Here, we present a broad phylogenetic analysis of the genus Atherina using three mitochondrial (control region, 12S and 16S) and two nuclear markers (rhodopsin and 2nd intron of S7). Phylogenetic analyses fully support the monophyly of the genus.
Abstract Environmental molecular surveys of microbial diversity have uncovered a vast number of novel taxonomic units in the eukaryotic tree of life that are exclusively known by their small-subunit (SSU) rRNA gene signatures. In this... more
Abstract Environmental molecular surveys of microbial diversity have uncovered a vast number of novel taxonomic units in the eukaryotic tree of life that are exclusively known by their small-subunit (SSU) rRNA gene signatures. In this study, we reveal the cellular and taxonomic identity of a novel eukaryote SSU rRNA gene sequence clade within the Kinetoplastea. Kinetoplastea are ubiquitously distributed flagellated protists of high ecological and medical importance.
Abstract Bodonid flagellates (class Kinetoplastea) are abundant, free-living protozoa in freshwater, soil and marine habitats, with undersampled global biodiversity.
ABSTRACT Euglenozoa is a major phylum of excavate protozoa (comprising euglenoids, kinetoplastids, and diplonemids) with highly unusual nuclear, mitochondrial, and chloroplast genomes. To improve understanding of euglenozoan evolution, we... more
ABSTRACT Euglenozoa is a major phylum of excavate protozoa (comprising euglenoids, kinetoplastids, and diplonemids) with highly unusual nuclear, mitochondrial, and chloroplast genomes. To improve understanding of euglenozoan evolution, we sequenced nuclear small-subunit rRNA genes from 34 bodonids (Bodo, Neobodo, Parabodo, Dimastigella-like, Rhynchobodo, Rhynchomonas, and unidentified strains), nine diplonemids (Diplonema, Rhynchopus), and a euglenoid (Entosiphon).
Abstract 'No-take'marine protected areas (MPAs) are successful in protecting populations of many exploited fish species, but it is often unclear whether networks of MPAs are adequately spaced to ensure connectivity among reserves, and... more
Abstract 'No-take'marine protected areas (MPAs) are successful in protecting populations of many exploited fish species, but it is often unclear whether networks of MPAs are adequately spaced to ensure connectivity among reserves, and whether there is spillover into adjacent exploited areas. Such issues are particularly important in species with low dispersal potential, many of which exist as genetically distinct regional stocks.
Intraspecific genetic structure in widely distributed marine species often mirrors the boundaries between temperature-defined bioregions. This suggests that the same thermal gradients that maintain distinct species assemblages also drive... more
Intraspecific genetic structure in widely distributed marine species often mirrors
the boundaries between temperature-defined bioregions. This suggests
that the same thermal gradients that maintain distinct species assemblages
also drive the evolution of new biodiversity. Ecological speciation scenarios
are often invoked to explain such patterns, but the fact that adaptation is
usually only identified when phylogenetic splits are already evident makes
it impossible to rule out the alternative scenario of allopatric speciation with
subsequent adaptation.We integrated large-scale genomic and environmental
datasets along one of the world’s best-defined marine thermal gradients
(the South African coastline) to test the hypothesis that incipient ecological
speciation is a result of divergence linked to the thermal environment. We
identified temperature-associated gene regions in a coastal fish species that
is spatially homogeneous throughout several temperature-defined biogeographic
regions based on selectively neutral markers. Based on these gene
regions, the species is divided into geographically distinct regional populations.
Importantly, the ranges of these populations are delimited by the
same ecological boundaries that define distinct infraspecific genetic lineages
in co-distributed marine species, and biogeographic disjunctions in species
assemblages. Our results indicate that temperature-mediated selection represents
an early stage of marine ecological speciation in coastal regions that
lack physical dispersal barriers.
the boundaries between temperature-defined bioregions. This suggests
that the same thermal gradients that maintain distinct species assemblages
also drive the evolution of new biodiversity. Ecological speciation scenarios
are often invoked to explain such patterns, but the fact that adaptation is
usually only identified when phylogenetic splits are already evident makes
it impossible to rule out the alternative scenario of allopatric speciation with
subsequent adaptation.We integrated large-scale genomic and environmental
datasets along one of the world’s best-defined marine thermal gradients
(the South African coastline) to test the hypothesis that incipient ecological
speciation is a result of divergence linked to the thermal environment. We
identified temperature-associated gene regions in a coastal fish species that
is spatially homogeneous throughout several temperature-defined biogeographic
regions based on selectively neutral markers. Based on these gene
regions, the species is divided into geographically distinct regional populations.
Importantly, the ranges of these populations are delimited by the
same ecological boundaries that define distinct infraspecific genetic lineages
in co-distributed marine species, and biogeographic disjunctions in species
assemblages. Our results indicate that temperature-mediated selection represents
an early stage of marine ecological speciation in coastal regions that
lack physical dispersal barriers.