ORCID Profile
0000-0001-5094-5510
Current Organisations
Macquarie University
,
CSIRO
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Publisher: Proceedings of the National Academy of Sciences
Date: 08-11-2022
Abstract: Invasive rodents are a major cause of environmental damage and bio ersity loss, particularly on islands. Unlike insects, genetic biocontrol strategies including population-suppressing gene drives with biased inheritance have not been developed in mice. Here, we demonstrate a gene drive strategy ( t CRISPR ) that leverages super-Mendelian transmission of the t haplotype to spread inactivating mutations in a haplosufficient female fertility gene ( Prl ). Using spatially explicit in idual-based in silico modeling, we show that t CRISPR can eradicate island populations under a range of realistic field-based parameter values. We also engineer transgenic t CRISPR mice that, crucially, exhibit biased transmission of the modified t haplotype and Prl mutations at levels our modeling predicts would be sufficient for eradication. This is an ex le of a feasible gene drive system for invasive alien rodent population control.
Publisher: Wiley
Date: 08-2008
DOI: 10.1111/J.1558-5646.2008.00428.X
Abstract: Divergent selection on traits involved in both local adaptation and the production of mating signals can strongly facilitate population differentiation. Because of its links to foraging morphologies and cultural inheritance song of birds can contribute particularly strongly to maintenance of local adaptations. In two adjacent habitats--native Sonoran desert and urban areas--house finches (Carpodacus mexicanus) forage on seeds that are highly distinct in size and shell hardness and require different bite forces and bill morphologies. Here, we first document strong and habitat-specific natural selection on bill traits linked to bite force and find adaptive modifications of bite force and bill morphology and associated ergence in courtship song between the two habitats. Second, we investigate the developmental basis of this ergence and find that early ontogenetic tissue transformation in bill, but not skeletal traits, is accelerated in the urban population and that the mandibular primordia of the large-beaked urban finches express bone morphogenetic proteins (BMP) earlier and at higher level than those of the desert finches. Further, we show that despite being geographically adjacent, urban and desert populations are nevertheless genetically distinct corroborating findings of early developmental ergence between them. Taken together, these results suggest that ergent selection on function and development of traits involved in production of mating signals, in combination with localized learning of such signals, can be very effective at maintaining local adaptations, even at small spatial scales and in highly mobile animals.
Publisher: University of Chicago Press
Date: 09-2010
DOI: 10.1086/655216
Abstract: The social environment is a critical determinant of fitness and, in many taxa, is shaped by an in idual's behavioral discrimination among social contexts, suggesting that animals can actively influence the selection they experience. In competition to attract females, males may modify sexual selection by choosing social environments in which they are more attractive relative to rivals. Across the population, such behaviors should influence sexual selection patterns by altering the relationship between male mating success and sexual ornament elaboration. Here we use network analysis to examine patterns of male social behavior in relation to plumage ornamentation and mating success in a free-living population of house finches. During the nonbreeding season, less elaborate males changed associations with distinct social groups more frequently, compared to more elaborate males that showed greater fidelity to a single social group. By the onset of pair formation, socially labile males effectively increased their attractiveness relative to other males in the same flocks. Consequently, males that frequently moved between social groups had greater pairing success than less social in iduals with equivalent sexual ornamentation. We discuss these results in relation to conditional mating tactics and the role of social behavior in evolutionary change by sexual selection.
Publisher: Frontiers Media SA
Date: 25-05-2020
Publisher: The Royal Society
Date: 06-11-2019
Abstract: Invasive rodents impact bio ersity, human health and food security worldwide. The bio ersity impacts are particularly significant on islands, which are the primary sites of vertebrate extinctions and where we are reaching the limits of current control technologies. Gene drives may represent an effective approach to this challenge, but knowledge gaps remain in a number of areas. This paper is focused on what is currently known about natural and developing synthetic gene drive systems in mice, some key areas where key knowledge gaps exist, findings in a variety of disciplines relevant to those gaps and a brief consideration of how engagement at the regulatory, stakeholder and community levels can accompany and contribute to this effort. Our primary species focus is the house mouse, Mus musculus , as a genetic model system that is also an important invasive pest. Our primary application focus is the development of gene drive systems intended to reduce reproduction and potentially eliminate invasive rodents from islands. Gene drive technologies in rodents have the potential to produce significant benefits for bio ersity conservation, human health and food security. A broad-based, multidisciplinary approach is necessary to assess this potential in a transparent, effective and responsible manner.
Publisher: Springer Science and Business Media LLC
Date: 2008
Publisher: Proceedings of the National Academy of Sciences
Date: 26-09-2017
Abstract: Duration of developmental stages in animals evolves under contrasting selection pressures of age-specific mortality and growth requirements. When relative importance of these effects varies across environments, evolution of developmental periods is expected to be slow. In birds, maternal effects on egg-laying order and offspring growth, two proximate determinants of nestling period, should enable rapid adjustment of developmental periods to even widely fluctuating mortality rates. We test this hypothesis in a population of house finches ( Carpodacus mexicanus ) breeding under two contrasting mortality risks: ( i ) a nest mite-free condition when selection on offspring survival favors a longer time in the nest and ( ii ) a mite infestation when selection favors a shorter nest tenure. Mites affected survival of sons more than daughters, and females breeding under mite infestation laid male eggs last and female eggs first in the clutch, thereby reducing sons' exposure to mites and associated mortality. Strong sex bias in laying order and growth patterns enabled mite-infested offspring to achieve similar fledging size, despite a shorter nest tenure, compared with mite-free conditions. In mite-infested nests, male nestlings hatched at larger sizes, completed growth earlier, and had faster initial growth compared with mite-free nests, whereas mite-infested females grew more slowly but for a longer period of time. A combination of heavily sex-biased laying order and sex differences in growth patterns lowered mite-induced mortality by % in both sexes. Thus, strong maternal effects can account for frequently observed, but theoretically unexpected, concordance of mortality risks and growth patterns, especially under fluctuating ecological conditions.
Publisher: Wiley
Date: 22-06-2011
DOI: 10.1111/J.1365-294X.2011.05118.X
Abstract: Social monogamy is nearly ubiquitous across avian taxa,but evidence from a proliferation of studies utilizing molecular paternity analysis suggests that sexual monogamy is the rare exception rather than the rule (Griffith et al. 2002). Efforts to explain the prevalence of extra-pair paternity (EPP) have largely focused on the potential fitness benefits for offspring genetic quality, as females are less likely to benefit directly from seeking extra-pair mates. In particular, there has been considerable interest in the degree to which EPP may represent an adaptive female strategy to avoid inbreeding (or outbreeding)depression when paired with a highly related (or unrelated)social mate (Kempenaers 2007). Others have argued that, because relatives share many genes identical by descent,females might increase their own inclusive fitness by providing additional breeding opportunities to genetically related males (Waser et al. 1986 Kokko & Ots 2006). Thus, in the absence of significant inbreeding depression, pursuing EPP with relatives should be favoured by kin selection, although there exist few unambiguous empirical ex les of such preferences in the literature. In this issue of Molecular Ecology, Wang &Lu (2011) present an analysis of mating patterns with respect to genetic relatedness of social and extra-pair partners in the ground tit (Parus humilis), a facultative cooperative breeder in which socially monogamous pairs occasionally form cooperative groups with unpaired helper males (Fig. 1). Consistent with the predictions of the kin-selection hypothesis, females in both bi-parental and cooperative groups preferentially engaged in extra-pair matings with relatives, irrespective of relatedness to their social mates, and while suffering no apparent costs of inbreeding depression in their progeny. These finding shave several exciting implications for our understanding of avian mating system ersity and the evolution of cooperative breeding.
Publisher: Wiley
Date: 29-11-2005
DOI: 10.1111/J.1420-9101.2005.01041.X
Abstract: In species that produce broods of multiple offspring, parents need to partition resources among simultaneously growing neonates that often differ in growth requirements. In birds, multiple ovarian follicles develop inside the female at the same time, resulting in a trade-off of resources among them and potentially limiting maternal ability for sex-specific allocation. We compared resource acquisition among oocytes in relation to their future sex and ovulation order in two populations of house finches with contrasting sex-biased maternal strategies. In a native Arizona population, where mothers do not bias offspring sex in relation to ovulation order, the male and female oocytes did not show sex-specific trade-offs of resources during growth and there was no evidence for spatial or temporal segregation of male and female oocytes in the ovary. In contrast, in a recently established Montana population where mothers strongly bias offspring sex in relation to ovulation order, we found evidence for both intra-sexual trade-offs among male and female oocytes and sex-specific clustering of oocytes in the ovary. We discuss the importance of sex-specific resource competition among offspring for the evolution of sex-ratio adjustment and sex-specific maternal resource allocation.
Publisher: Wiley
Date: 03-2007
Publisher: Wiley
Date: 20-04-2009
DOI: 10.1111/J.1755-0998.2009.02555.X
Abstract: The house finch (Carpodacus mexicanus) has emerged recently as a model species in studies of sexual selection, reproductive physiology, population genetics, and epizootic disease ecology. Here we describe 17 highly polymorphic microsatellite loci for this species. In a s le of 36 in iduals, we observed an average of 16 alleles per locus and heterozygosity ranged from 0.61 to 0.97. One locus showed significant deviation from Hardy-Weinberg proportions, but no significant gametic disequilibrium was observed among any of the loci. Amplification by polymerase chain reaction was optimized under similar parameters across loci, thereby facilitating multiplexing and rapid multilocus genotyping.
Publisher: Springer Science and Business Media LLC
Date: 11-2019
DOI: 10.1038/S41598-019-51994-0
Abstract: Invasive species pose a major threat to bio ersity on islands. While successes have been achieved using traditional removal methods, such as toxicants aimed at rodents, these approaches have limitations and various off-target effects on island ecosystems. Gene drive technologies designed to eliminate a population provide an alternative approach, but the potential for drive-bearing in iduals to escape from the target release area and impact populations elsewhere is a major concern. Here we propose the “Locally Fixed Alleles” approach as a novel means for localizing elimination by a drive to an island population that exhibits significant genetic isolation from neighboring populations. Our approach is based on the assumption that in small island populations of rodents, genetic drift will lead to alleles at multiple genomic loci becoming fixed. In contrast, multiple alleles are likely to be maintained in larger populations on mainlands. Utilizing the high degree of genetic specificity achievable using homing drives, for ex le based on the CRISPR/Cas9 system, our approach aims at employing one or more locally fixed alleles as the target for a gene drive on a particular island. Using mathematical modeling, we explore the feasibility of this approach and the degree of localization that can be achieved. We show that across a wide range of parameter values, escape of the drive to a neighboring population in which the target allele is not fixed will at most lead to modest transient suppression of the non-target population. While the main focus of this paper is on elimination of a rodent pest from an island, we also discuss the utility of the locally fixed allele approach for the goals of population suppression or population replacement. Our analysis also provides a threshold condition for the ability of a gene drive to invade a partially resistant population.
Publisher: Cold Spring Harbor Laboratory
Date: 31-05-2022
DOI: 10.1101/2022.05.31.494104
Abstract: Invasive rodents, including house mice, are a major cause of environmental damage and bio ersity loss, particularly in island ecosystems. Eradication can be achieved through the distribution of rodenticide, but this approach is expensive to apply at scale, can have negative impacts (e.g. on non-target species, or through contamination), has animal ethics concerns, and has restrictions on where it can be used. Gene drives, which exhibit biased inheritance, have been proposed as a next generation strategy to control invasive alien pests and disease vectors. However, synthetic gene drives including CRISPR homing drives have proven to be technically challenging to develop in mice. The t haplotype is a naturally-occurring segregation distortion locus with highly biased transmission from heterozygous males. Here we propose a novel gene drive strategy for population suppression, t CRISPR , that leverages t haplotype bias and an embedded SpCas9/gRNA transgene to spread inactivating mutations in a haplosufficient female fertility gene. Using spatially explicit in idual-based in silico modelling, we show that polyandry, sperm competition, dispersal, and transmission bias are critical factors for t CRISPR -mediated population suppression. Modelling of realistic parameter values indicates that t CRISPR can eradicate an island population of 200,000 mice while the unmodified t haplotype fails under the same conditions. We also demonstrate feasibility of this approach by engineering t CRISPR mice in a safe split drive format. t CRISPR mice exhibit high transmission of the modified t haplotype, and efficient generation and transmission of inactivating mutations in a recessive female fertility gene, crucially, at levels for which the modelling predicts that population eradication can occur. This is the first ex le of a feasible gene drive system for invasive alien rodent population control.
Publisher: The Royal Society
Date: 22-06-2013
Abstract: Estimating the fitness surface of rapidly evolving secondary sexual traits can elucidate the origins of sexual isolation and thus speciation. Evidence suggests that sexual selection is highly complex in nature, often acting on multivariate sexual characters that sometimes include non-heritable components of variation, thus presenting a challenge for predicting patterns of sexual trait evolution. Laupala crickets have undergone an explosive species radiation marked by ergence in male courtship song and associated female preferences, yet patterns of sexual selection that might explain this ersification remain unknown. We used female phonotaxis trials to estimate the fitness surface for acoustic characters within one population of Laupala cerasina , a species with marked geographical variation in male song and female preferences. Results suggested significant directional sexual selection on three major song traits, while canonical rotation of the matrix of nonlinear selection coefficients ( γ ) revealed the presence of significant convex (stabilizing) sexual selection along combinations of characters. Analysis of song variation within and among males indicated significantly higher repeatability along the canonical axis of greatest stabilizing selection than along the axis of greatest linear selection. These results are largely consistent with patterns of song ergence that characterize speciation and suggest that different song characters have the potential to indicate distinct information to females during courtship.
Publisher: The Royal Society
Date: 09-10-2019
Abstract: When the same phenotype evolves repeatedly, we can explore the predictability of genetic changes underlying phenotypic evolution. Theory suggests that genetic parallelism is less likely when phenotypic changes are governed by many small-effect loci compared to few of major effect, because different combinations of genetic changes can result in the same quantitative outcome. However, some genetic trajectories might be favoured over others, making a shared genetic basis to repeated polygenic evolution more likely. To examine this, we studied the genetics of parallel male mating song evolution in the Hawaiian cricket Laupala . We compared quantitative trait loci (QTL) underlying song ergence in three species pairs varying in phenotypic distance. We tested whether replicated song ergence between species involves the same QTL and whether the likelihood of QTL sharing is related to QTL effect size. Contrary to theoretical predictions, we find substantial parallelism in polygenic genetic architectures underlying repeated song ergence. QTL overlapped more frequently than expected based on simulated QTL analyses. Interestingly, QTL effect size did not predict QTL sharing, but did correlate with magnitude of phenotypic ergence. We highlight potential mechanisms driving these constraints on cricket song evolution and discuss a scenario that consolidates empirical quantitative genetic observations with micro-mutational theory.
Publisher: Oxford University Press (OUP)
Date: 04-2013
Abstract: Sexual isolation resulting from differences in mate choice behaviors is a hallmark of rapidly-speciating lineages. When present, asymmetrical sexual isolation may provide insights into the mechanisms responsible for the evolutionary change in mate signaling traits. In particular, Kaneshiro’s hypothesis suggests that ergence in sexual characters between populations may arise in allopatry when ‘derived’ founding populations are subject to severe population bottlenecks, accompanied by a relaxation of sexual selection relative to ‘ancestral’ source populations. In the present study, we tested predictions of asymmetrical sexual isolation between two allopatric species of Hawaiian Laupala crickets, representing ‘ancestral’ (L. makaio) and ‘derived’ (L. nigra) taxa. While crickets in this genus are notable for rapid ergence of male courtship songs, these species share similar song types, thus suggesting that patterns of sexual isolation are likely due to other mating cues. Analysis of behavioral responses in conspecific and heterospecific ‘no-choice’ mating trials revealed pronounced asymmetrical isolation in the direction predicted by Kaneshiro’s hypothesis, wherein we observed a significant reduction in mating success for crosses involving ‘derived’ males paired with ‘ancestral’ females, compared to the reciprocal heterospecific and both conspecific pairings. Further dissection of courtship behaviors suggested this difference did not reflect male mate choice, but rather, marked reduced spermatophore acceptance rates by ‘ancestral’ females paired with ‘derived’ males. The results are discussed with respect to founder effect models of speciation and the potential role of chemosensory signals in mate choice in these species.
Publisher: Springer International Publishing
Date: 2020
Publisher: CSIRO Publishing
Date: 18-07-2022
DOI: 10.1071/WR22009
Abstract: Context Recent studies have shown that the sensitivity of wild house mice to zinc phosphide (ZnP) in Australia is significantly lower than previously assumed, which may account for the reported variability in efficacy of ZnP baits used for broadacre control of house mice in grain-growing regions. Under laboratory conditions ZnP-coated grains with a new higher dose (50 g ZnP/kg grain) were readily consumed but the efficacy of using grains with this higher dose under natural field conditions has not been tested. Aims To test whether the newly derived ZnP50 (50 g ZnP/kg grain) was more effective under field conditions than the currently registered ZnP25 (25 g ZnP/kg grain) in reducing populations of house mice during a mouse population irruption. Methods We used a before–after-control–impact (BACI) design to assess changes in mouse population size under different baiting treatments in a replicated field trial. We assessed changes in mouse abundance in recently sown paddocks with either ZnP50 (n = 3) or ZnP25 (n = 3) compared with unbaited control sites (n = 3). Key results Baiting with ZnP50 led to a median reduction in mouse numbers of %. Our modelling showed that under similar circumstances, using the ZnP50 formulation should deliver % reduction in population size most ( %) of the time. In contrast, the current registered bait (ZnP25) achieved approximately 70% reduction in population size, but with more variable results. We would be confident of getting an 80% reduction in population size only 20% of the time by using the currently registered ZnP25 bait under similar field conditions. Conclusions Consistent with laboratory studies, this study demonstrated the higher probability of achieving a consistently high kill rate under field conditions with the new ZnP50 bait compared with the currently registered formulation (ZnP25). Implications By using the new ZnP50 bait, farmers are far more likely to get good kill rates, thereby reducing the need for repeated baiting (which is costly and generally ineffective at protecting newly sown crops). Using the new bait should result in lower control costs for farmers and fewer toxic grains being spread to control mice.
Publisher: Public Library of Science (PLoS)
Date: 17-08-2023
DOI: 10.1371/JOURNAL.PONE.0288701
Abstract: The management of invasive species has been greatly enhanced by population genetic analyses of multilocus single-nucleotide polymorphism (SNP) datasets that provide critical information regarding pest population structure, invasion pathways, and reproductive biology. For many applications there is a need for protocols that offer rapid, robust and efficient genotyping on the order of hundreds to thousands of SNPs, that can be tailored to specific study populations and that are scalable for long-term monitoring schemes. Despite its status as a model laboratory species, there are few existing resources for studying wild populations of house mice ( Mus musculus spp.) that strike this balance between data density and laboratory efficiency. Here we evaluate the utility of a custom targeted capture genotyping-by-sequencing approach to support research on plaguing house mouse populations in Australia. This approach utilizes 3,651 hybridization capture probes targeting genome-wide SNPs identified from a s le of mice collected in grain-producing regions of southeastern Australia genotyped using a commercially available microarray platform. To assess performance of the custom panel, we genotyped wild caught mice (N = 320) from two adjoining farms and demonstrate the ability to correctly assign in iduals to source populations with high confidence (mean %), as well as robust kinship inference within sites. We discuss these results in the context of proposed applications for future genetic monitoring of house mice in Australia.
Publisher: Oxford University Press (OUP)
Date: 28-05-2019
DOI: 10.1093/GBE/EVZ112
Abstract: Sage-grouse are two closely related iconic species of the North American West, with historically broad distributions across sagebrush-steppe habitat. Both species are dietary specialists on sagebrush during winter, with presumed adaptations to tolerate the high concentrations of toxic secondary metabolites that function as plant chemical defenses. Marked range contraction and declining population sizes since European settlement have motivated efforts to identify distinct population genetic variation, particularly that which might be associated with local genetic adaptation and dietary specialization of sage-grouse. We assembled a reference genome and performed whole-genome sequencing across sage-grouse from six populations, encompassing both species and including several populations on the periphery of the species ranges. Population genomic analyses reaffirmed genome-wide differentiation between greater and Gunnison sage-grouse, revealed pronounced intraspecific population structure, and highlighted important differentiation of a small isolated population of greater sage-grouse in the northwest of the range. Patterns of genome-wide differentiation were largely consistent with a hypothesized role of genetic drift due to limited gene flow among populations. Inferred ancient population demography suggested persistent declines in effective population sizes that have likely contributed to differentiation within and among species. Several genomic regions with single-nucleotide polymorphisms exhibiting extreme population differentiation were associated with candidate genes linked to metabolism of xenobiotic compounds. In vitro activity of enzymes isolated from sage-grouse livers supported a role for these genes in detoxification of sagebrush, suggesting that the observed interpopulation variation may underlie important local dietary adaptations, warranting close consideration for conservation strategies that link sage-grouse to the chemistry of local sagebrush.
Publisher: Springer Science and Business Media LLC
Date: 09-2009
Publisher: Wiley
Date: 09-07-2019
DOI: 10.1111/EVA.12825
Publisher: Springer Science and Business Media LLC
Date: 20-03-2008
Publisher: The Royal Society
Date: 18-04-2006
Abstract: Choice of genetically unrelated mates is widely documented, yet it is not known how self-referential mate choice can co-occur with commonly observed directional selection on sexual displays. Across 10 breeding seasons in a wild bird population, we found strong fitness benefits of matings between genetically unrelated partners and show that self-referential choice of genetically unrelated mates alternates with sexual selection on elaborate plumage. Seasonal cycles of diminishing variation in ornamentation, caused by early pairing of the most elaborated males, and influx of increasingly genetically unrelated available mates caused by female-biased dispersal, lead to temporal fluctuations in the target of mate choice and enabled coexistence of directional selection for ornament elaboration with adaptive pairing of genetically unrelated partners.
Publisher: Oxford University Press (OUP)
Date: 06-06-2018
DOI: 10.1534/GENETICS.118.300894
Abstract: Phenotypic evolution and speciation depend on recombination in many ways. Within populations, recombination can promote adaptation by bringing together favorable mutations and decoupling beneficial and deleterious alleles. As populations erge, crossing over can give rise to maladapted recombinants and impede or reverse ersification. Suppressed recombination due to genomic rearrangements, modifier alleles, and intrinsic chromosomal properties may offer a shield against maladaptive gene flow eroding coadapted gene complexes. Both theoretical and empirical results support this relationship. However, little is known about this relationship in the context of behavioral isolation, where coevolving signals and preferences are the major hybridization barrier. Here we examine the genomic architecture of recently erged, sexually isolated Hawaiian swordtail crickets (Laupala). We assemble a de novo genome and generate three dense linkage maps from interspecies crosses. In line with expectations based on the species’ recent ergence and successful interbreeding in the laboratory, the linkage maps are highly collinear and show no evidence for large-scale chromosomal rearrangements. Next, the maps were used to anchor the assembly to pseudomolecules and estimate recombination rates across the genome to test the hypothesis that loci involved in behavioral isolation (song and preference ergence) are in regions of low interspecific recombination. Contrary to our expectations, the genomic region where a male song and female preference QTL colocalize is not associated with particularly low recombination rates. This study provides important novel genomic resources for an emerging evolutionary genetics model system and suggests that trait–preference coevolution is not necessarily facilitated by locally suppressed recombination.
Publisher: Frontiers Media SA
Date: 31-01-2022
DOI: 10.3389/FAGRO.2021.806569
Abstract: Managing pest vertebrate species in Australia is a significant challenge for government, industry, research sectors and land-managers. Innovative tools such as genetic biocontrol offers decision-makers a potentially effective means of reducing the impact of pest species incursions. To determine the conditions for investment in genetic biocontrol, we applied qualitative engagement methodologies to identify and integrate existing knowledge of pest species research and management in Australia. Two facilitated workshops were held to determine key topics related to genetic biocontrol technologies for selected pest species. The topics explored during workshop discussions included: identifying existing knowledge gaps risk perceptions social and ethical considerations and industry and business considerations. The workshops' aim was to assess the potential, the priorities and the risk parameters among expert stakeholders and decision-makers for using genetic biocontrol approaches to reduce the impacts of key pest species in Australia. This paper reports on the design, process and outcomes of each workshop to inform the creation of a decision framework. Stakeholders were cautiously optimistic of pursuing continued research and development for vertebrate pest management in Australia. However, employing an appropriate, transparent process for incorporating erse stakeholder perspectives on genetic biocontrol technologies is essential to ensure their development and use remains supported. This outcome will require meaningful investment in both social science investigations and well-considered engagement processes concurrent with biotechnology development globally.
Publisher: Wiley
Date: 10-03-2021
DOI: 10.1111/EVA.13210
Abstract: Introduced rodent populations pose significant threats worldwide, with particularly severe impacts on islands. Advancements in genome editing have motivated interest in synthetic gene drives that could potentially provide efficient and localized suppression of invasive rodent populations. Application of such technologies will require rigorous population genomic surveys to evaluate population connectivity, taxonomic identification, and to inform design of gene drive localization mechanisms. One proposed approach leverages the predicted shifts in genetic variation that accompany island colonization, wherein founder effects, genetic drift, and island‐specific selection are expected to result in locally fixed alleles (LFA) that are variable in neighboring nontarget populations. Engineering of guide RNAs that target LFA may thus yield gene drives that spread within invasive island populations, but would have limited impacts on nontarget populations in the event of an escape. Here we used pooled whole‐genome sequencing of invasive mouse ( Mus musculus ) populations on four islands along with paired putative source populations to test genetic predictions of island colonization and characterize locally fixed Cas9 genomic targets. Patterns of variation across the genome reflected marked reductions in allelic ersity in island populations and moderate to high degrees of differentiation from nearby source populations despite relatively recent colonization. Locally fixed Cas9 sites in female fertility genes were observed in all island populations, including a small number with multiplexing potential. In practice, rigorous s ling of presumptive LFA will be essential to fully assess risk of resistance alleles. These results should serve to guide development of improved, spatially limited gene drive design in future applications.
Publisher: Wiley
Date: 16-05-2012
DOI: 10.1111/J.1420-9101.2012.02531.X
Abstract: Understanding the genetic architecture of traits involved in premating isolation between recently erged lineages can provide valuable insight regarding the mode and tempo of speciation. The repeated coevolution of male courtship song and female preference across the species radiation of Laupala crickets presents an unusual opportunity to compare the genetic basis of ergence across independent evolutionary histories. Previous studies of one pair of species revealed a polygenic basis (including a significant X chromosome contribution) to quantitative differences in male song and female acoustic preference. Here, we studied interspecific crosses between two phenotypically less- erged species that represents a phylogenetically independent occurrence of intersexual signalling evolution. We found patterns consistent with an additive polygenic basis to differentiation in both song and preference (n(E) = 5.3 and 5.1 genetic factors, respectively), and estimate a moderate contribution of the X chromosome (7.6%) of similar magnitude to that observed for Laupala species with nearly twice the phenotypic ergence. Together, these findings suggest a similar genetic architecture underlying the repeated evolution of sexual characters in this genus and provide a counterex le to prevailing theory predicting an association between early lineage ergence and sex-linked 'major genes'.
Publisher: Oxford University Press (OUP)
Date: 06-08-2011
Publisher: Springer International Publishing
Date: 2020
Publisher: MDPI AG
Date: 10-07-2018
DOI: 10.3390/GENES9070346
Publisher: Wiley
Date: 28-10-2021
DOI: 10.1111/JEB.13951
Abstract: Sexual signalling traits are often observed to erge rapidly among populations, thereby playing a potentially key early role in the evolution of reproductive isolation. While often assumed to reflect ergent sexual selection among populations, patterns of sexual trait ersification might sometimes be biased along axes of standing additive genetic variation and covariation among trait components. Additionally, theory predicts that environmentally induced phenotypic variation might facilitate rapid trait evolution, suggesting that patterns of ergence between populations should mirror phenotypic plasticity within populations. Here, we evaluate the concordance between observed axes of multivariate sexual trait ergence and predicted ergence based on (1) interpopulation variation in sexual selection, (2) additive genetic variances and (3) temperature‐related phenotypic plasticity in male courtship song among geographically isolated populations of the Hawaiian swordtail cricket, Laupala cerasina , which exhibit sexual isolation due acoustic signalling traits. The major axis of multivariate ergence, d max , accounted for 76% of variation among population male song trait means and was moderately correlated with interpopulation differences in directional sexual selection based on female preferences. However, the majority of additive genetic variance was largely oriented away from the direction of ergence, suggesting that standing genetic variation may not play a dominant role in the patterning of signal ergence. In contrast, the axis of phenotypic plasticity strongly mirrored patterns of interpopulation phenotypic ergence, which is consistent with a role for temperature‐related plasticity in facilitating instead of inhibiting male song evolution and sexual isolation in these incipient species. We propose potential mechanisms by which sexual selection might interact with phenotypic plasticity to facilitate the rapid acoustic ersification observed in this species and clade.
Location: Australia
No related grants have been discovered for Kevin Oh.