W. Jason Kennington

University of Western Australia

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Joseph L. Tomkins

University of Western Australia

Jonathan P. Evans

University of Western Australia

Linda Partridge

MRC Unit for Lifelong Health and Ageing

Luke Thomas

University of Western Australia

Leigh W. Simmons

University of Western Australia

Oliver Berry

University of Western Australia

Robert J. Dugand

University of Western Australia

Rowan A. Lymbery

University of Western Australia

Kym Ottewell

University of Western Australia

Zoe T. Richards

Western Australian Museum

Cooperative Institutions

University of Western Australia

116

Australian Institute of Marine Science

Government of Western Australia

Curtin University

University College London

University of Sheffield

University of Oxford

Australian National University

Centre National de la Recherche Scientifique

Université de Montpellier

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Volatile leaf oil diversity in the narrow range endemic Eucalyptus argutifolia (Myrtaceae) and its widespread congener Eucalyptus obtusiflora

Biological Journal of the Linnean Society (2009)

W. Jason Kennington

Variation in the qualitative composition of volatile leaf oil was examined in the rare Eucalyptus argutifolia and its widespread congener Eucalyptus obtusiflora. The results revealed that, consistent with the pattern seen with allozymes, E. argutifolia had less variation within populations than E. obtusiflora. Total leaf oil diversity was also significantly lower in the rare species. As found with allozymes, most leaf oil diversity was within populations, but there was also a significant proportion of the variation between populations (25.2% and 27.3% for E. argutifolia and E. obtusiflora, respectively). There were significant associations between phenotypic distance based on leaf oils and geographical distance and between phenotypic and genetic distance across all populations, but these associations were not evident within species. Factors leading to reduced variation in E. argutifolia appear to affect all types of variation, but the relationships between different types of variation within the species are less apparent.

Myrtaceae

Congener

10.1111/j.1095-8312.2008.01175.x

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Citations (2)

MORE THAN BINDIN DIVERGENCE: REPRODUCTIVE ISOLATION BETWEEN SYMPATRIC SUBSPECIES OF A SEA URCHIN BY ASYNCHRONOUS SPAWNING

Evolution (2012)

Rachel M. Binks Jane Prince Jonathan P. Evans W. Jason Kennington

The evolution of reproductive barriers is crucial to the process of speciation. In the Echinoidea, studies have focused on divergence in the gamete recognition protein, bindin, as the primary isolating mechanism among species. As such, the capacity of alternate mechanisms to be effective reproductive barriers and the phylogenetic context in which they arise is unclear. Here, we examine the evolutionary histories and factors limiting gene exchange between two subspecies of Heliocidaris erythrogramma that occur sympatrically in Western Australia. We found low, but significant differentiation between the subspecies in two mitochondrial genes. Further, coalescent analyses suggest that they diverged in isolation on the east and west coasts of Australia, with a subsequent range expansion of H. e. erythrogramma into Western Australia. Differentiation in bindin was minimal, indicating gamete incompatibility is an unlikely reproductive barrier. We did, however, detect strong asynchrony in spawning seasons; H. e. erythrogramma spawned over summer whereas H. e. armigera spawned in autumn. Taken together, we provide compelling evidence for a recent divergence of these subspecies and their reproductive isolation without gamete incompatibility. Western Australian H. erythrogramma may therefore present an intriguing case of incipient speciation, which depends on long-term persistence of the factors underlying this spawning asynchrony.

Reproductive isolation

Subspecies

Gamete

Coalescent theory

Incipient speciation

Genetic algorithm

10.1111/j.1558-5646.2012.01700.x

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Citations (45)

RAPID LABORATORY EVOLUTION OF ADULT WING AREA IN DROSOPHILA MELANOGASTER IN RESPONSE TO HUMIDITY

Evolution (2003)

W. Jason Kennington James R. Killeen David B. Goldstein Linda Partridge

Abstract We examined the evolutionary response of wing area (a trait highly correlated with other measures of body size) to relative humidity (RH), temperature, and their interaction in Drosophila melanogaster, using replicated lines that had been allowed to evolve at low or high humidity at 18°C or at 25°C. We found that after 20 weeks of selection (5–10 generations), low RH lines had significantly greater wing areas than high RH lines in both sexes. This evolutionary response may have resulted from selection of larger flies with a smaller surface area for water loss relative to their weight, or as a correlated response to selection on some other unidentified trait. There were no evolutionary effects of temperature on wing area or cell density. This may have been due to the short duration of the selection experiment, and/or counteracting selection pressures on body size at warm temperature.

10.1111/j.0014-3820.2003.tb00304.x

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Citations (36)

Ocean acidification during prefertilization chemical communication affects sperm success

Ecology and Evolution (2019)

Rowan A. Lymbery W. Jason Kennington Christopher E. Cornwall Jonathan P. Evans

Ocean acidification (OA) poses a major threat to marine organisms, particularly during reproduction when externally shed gametes are vulnerable to changes in seawater pH. Accordingly, several studies on OA have focused on how changes in seawater pH influence sperm behavior and/or rates of in vitro fertilization. By contrast, few studies have examined how pH influences prefertilization gamete interactions, which are crucial during natural spawning events in most externally fertilizing taxa. One mechanism of gamete interaction that forms an important component of fertilization in most taxa is communication between sperm and egg-derived chemicals. These chemical signals, along with the physiological responses in sperm they elicit, are likely to be highly sensitive to changes in seawater chemistry. In this study, we experimentally tested this possibility using the blue mussel, Mytilus galloprovincialis, a species in which females have been shown to use egg-derived chemicals to promote the success of sperm from genetically compatible males. We conducted trials in which sperm were allowed to swim in gradients of egg-derived chemicals under different seawater CO2 (and therefore pH) treatments. We found that sperm had elevated fertilization rates after swimming in the presence of egg-derived chemicals in low pH (pH 7.6) compared with ambient (pH 8.0) seawater. This observed effect could have important implications for the reproductive fitness of external fertilizers, where gamete compatibility plays a critical role in modulating reproduction in many species. For example, elevated sperm fertilization rates might disrupt the eggs' capacity to avoid fertilizations by genetically incompatible sperm. Our findings highlight the need to understand how OA affects the multiple stages of sperm-egg interactions and to develop approaches that disentangle the implications of OA for female, male, and population fitness.

Gamete

Ocean Acidification

10.1002/ece3.5720

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Citations (12)

Heat stress mediates toxicity of rutile titanium dioxide nanoparticles on fertilisation capacity in the broadcast spawning mussel Mytilus galloprovincialis

The Science of The Total Environment (2024)

Annika Dose W. Jason Kennington Jonathan P. Evans

Titanium dioxide nanoparticle (nTiO

Rutile

Titanium Dioxide

10.1016/j.scitotenv.2024.175567

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Citations (1)

Patterns of genetic variation across inversions: geographic variation in the In(2L)t inversion in populations of Drosophila melanogaster from eastern Australia

BMC Evolutionary Biology (2013)

W. Jason Kennington Ary A. Hoffmann

Chromosomal inversions are increasingly being recognized as important in adaptive shifts and are expected to influence patterns of genetic variation, but few studies have examined genetic patterns in inversion polymorphisms across and within populations. Here, we examine genetic variation at 20 microsatellite loci and the alcohol dehydrogenase gene (Adh) located within and near the In(2L)t inversion of Drosophila melanogaster at three different sites along a latitudinal cline on the east coast of Australia. We found significant genetic differentiation between the standard and inverted chromosomal arrangements at each site as well as significant, but smaller differences among sites in the same arrangement. Genetic differentiation between pairs of sites was higher for inverted chromosomes than standard chromosomes, while inverted chromosomes had lower levels of genetic variation even well away from inversion breakpoints. Bayesian clustering analysis provided evidence of genetic exchange between chromosomal arrangements at each site. The strong differentiation between arrangements and reduced variation in the inverted chromosomes are likely to reflect ongoing selection at multiple loci within the inverted region. They may also reflect lower effective population sizes of In(2L)t chromosomes and colonization of Australia, although there was no consistent evidence of a recent bottleneck and simulations suggest that differences between arrangements would not persist unless rates of gene exchange between them were low. Genetic patterns therefore support the notion of selection and linkage disequilibrium contributing to inversion polymorphisms, although more work is needed to determine whether there are spatially varying targets of selection within this inversion. They also support the idea that the allelic content within an inversion can vary between geographic locations.

Chromosomal inversion

Cline (biology)

Linkage Disequilibrium

10.1186/1471-2148-13-100

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Citations (29)

Heritable variation in heat shock gene expression: a potential mechanism for adaptation to thermal stress in embryos of sea turtles

Proceedings of the Royal Society B Biological Sciences (2016)

Jamie N. Tedeschi W. Jason Kennington Joseph L. Tomkins Oliver Berry Scott D. Whiting

The capacity of species to respond adaptively to warming temperatures will be key to their survival in the Anthropocene. The embryos of egg-laying species such as sea turtles have limited behavioural means for avoiding high nest temperatures, and responses at the physiological level may be critical to coping with predicted global temperature increases. Using the loggerhead sea turtle ( Caretta caretta ) as a model, we used quantitative PCR to characterise variation in the expression response of heat-shock genes ( hsp60, hsp70 and hsp90; molecular chaperones involved in cellular stress response) to an acute non-lethal heat shock. We show significant variation in gene expression at the clutch and population levels for some, but not all hsp genes. Using pedigree information, we estimated heritabilities of the expression response of hsp genes to heat shock and demonstrated both maternal and additive genetic effects. This is the first evidence that the heat-shock response is heritable in sea turtles and operates at the embryonic stage in any reptile. The presence of heritable variation in the expression of key thermotolerance genes is necessary for sea turtles to adapt at a molecular level to warming incubation environments.

Ectotherm

10.1098/rspb.2015.2320

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Citations (60)

Evolutionary divergence via sexual selection acting on females in a species with sex role reversal

Functional Ecology (2022)

Robin M. Hare W. Jason Kennington Leigh W. Simmons

Abstract There is much evidence that sexual selection drives the evolutionary divergence of male sexual traits, but little is known of females. Comparisons between neutral genetic divergence ( F ST ) and phenotypic divergence ( P ST ) among populations can reveal evolutionary responses to selection. In the bushcricket Kawanaphila nartee , changes in floral food availability cause sex roles to shift from competitive females and choosy males to choosy females and competitive males midway through the breeding season. Males call to attract females, and female auditory spiracle size is under sexual selection. We ask whether selection on females can drive an evolutionary divergence in auditory spiracle size among populations. We sampled 188 individuals from nine geographic locations and analysed 9478 neutral SNP loci and two phenotypic characters to estimate F ST and P ST respectively. We found that P ST for female auditory spiracle size far exceeded the global F ST , suggesting that female auditory spiracle size is subject to strong directional selection. We relate differences in phenotypic traits to differences in geological and floristic characteristics among the sites. Our data suggest that variation in sexual selection driven by variation in the floristic community on which this species feeds may contribute to the strength of directional selection acting on female K. nartee among populations. Together, these findings indicate that divergence among populations can be driven by sexual selection acting on females, even when that selection is temporary and circumscribed. Read the free Plain Language Summary for this article on the Journal blog.

Divergence (linguistics)

Directional selection

Ecological selection

Stabilizing selection

Sexual dimorphism

10.1111/1365-2435.14174

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Citations (4)

Population Genomics of Bettongia lesueur: Admixing Increases Genetic Diversity with no Evidence of Outbreeding Depression

Genes (2019)

Kate Rick Kym Ottewell Cheryl Lohr Rujiporn Thavornkanlapachai Margaret Byrne

Small and isolated populations are subject to the loss of genetic variation as a consequence of inbreeding and genetic drift, which in turn, can affect the fitness and long-term viability of populations. Translocations can be used as an effective conservation tool to combat this loss of genetic diversity through establishing new populations of threatened species, and to increase total population size. Releasing animals from multiple genetically diverged sources is one method to optimize genetic diversity in translocated populations. However, admixture as a conservation tool is rarely utilized due to the risks of outbreeding depression. Using high-resolution genomic markers through double-digest restriction site-associated sequencing (ddRAD-seq) and life history data collected over nine years of monitoring, this study investigates the genetic and fitness consequences of admixing two genetically-distinct subspecies of Bettongia lesueur in a conservation translocation. Using single nucleotide polymorphisms (SNPs) identified from 215 individuals from multiple generations, we found an almost 2-fold increase in genetic diversity in the admixed translocation population compared to the founder populations, and this was maintained over time. Furthermore, hybrid class did not significantly impact on survivorship or the recruitment rate and therefore we found no indication of outbreeding depression. This study demonstrates the beneficial application of mixing multiple source populations in the conservation of threatened species for minimizing inbreeding and enhancing adaptive potential and overall fitness.

Outbreeding depression

Genetic drift

Conservation Genetics

Population fragmentation

Effective population size

Captive breeding

Population viability analysis

10.3390/genes10110851

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Citations (22)

An Endangered Arboreal Specialist, the Western Ringtail Possum (Pseudocheirus occidentalis), Shows a Greater Genetic Divergence across a Narrow Artificial Waterway than a Major Road

PLoS ONE (2016)

Kaori Yokochi W. Jason Kennington Roberta Bencini

The fragmentation of habitats by roads and other artificial linear structures can have a profound effect on the movement of arboreal species due to their strong fidelity to canopies. Here, we used 12 microsatellite DNA loci to investigate the fine-scale spatial genetic structure and the effects of a major road and a narrow artificial waterway on a population of the endangered western ringtail possum (Pseudocheirus occidentalis) in Busselton, Western Australia. Using spatial autocorrelation analysis, we found positive genetic structure in continuous habitat over distances up to 600 m. These patterns are consistent with the sedentary nature of P. occidentalis and highlight their vulnerability to the effects of habitat fragmentation. Pairwise relatedness values and Bayesian cluster analysis also revealed significant genetic divergences across an artificial waterway, suggesting that it was a barrier to gene flow. By contrast, no genetic divergences were detected across the major road. While studies often focus on roads when assessing the effects of artificial linear structures on wildlife, this study provides an example of an often overlooked artificial linear structure other than a road that has a significant impact on wildlife dispersal leading to genetic subdivision.

Habitat Fragmentation

Genetic divergence

Arboreal locomotion

Fragmentation

10.1371/journal.pone.0146167

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Citations (17)