ORCID Profile
0000-0001-9217-3627
Current Organisation
University of Adelaide
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Publisher: Oxford University Press (OUP)
Date: 2008
Publisher: Wiley
Date: 31-01-2022
DOI: 10.1111/MEC.16361
Abstract: Invasive alien species continue to threaten global bio ersity. CRISPR-based gene drives, which can theoretically spread through populations despite imparting a fitness cost, could be used to suppress or eradicate pest populations. We develop an in idual-based, spatially explicit, stochastic model to simulate the ability of CRISPR-based homing and X chromosome shredding drives to eradicate populations of invasive house mice (Mus muculus) from islands. Using the model, we explore the interactive effect of the efficiency of the drive constructs and the spatial ecology of the target population on the outcome of a gene-drive release. We also consider the impact of polyandrous mating and sperm competition, which could compromise the efficacy of some gene-drive strategies. Our results show that both drive strategies could be used to eradicate large populations of mice. Whereas parameters related to drive efficiency and demography strongly influence drive performance, we find that sperm competition following polyandrous mating is unlikely to impact the outcome of an eradication effort substantially. Assumptions regarding the spatial ecology of mice influenced the probability of and time required for eradication, with short-range dispersal capacities and limited mate-search areas producing 'chase' dynamics across the island characterized by cycles of local extinction and recolonization by mice. We also show that highly efficient drives are not always optimal, when dispersal and mate-search capabilities are low. Rapid local population suppression around the introduction sites can cause loss of the gene drive before it can spread to the entire island. We conclude that, although the design of efficient gene drives is undoubtedly critical, accurate data on the spatial ecology of target species are critical for predicting the result of a gene-drive release.
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: 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: Zenodo
Date: 2022
Publisher: Wiley
Date: 05-02-2018
DOI: 10.1002/AJPA.23423
Abstract: North Mesopotamia has witnessed dramatic social change during the Holocene, but the impact of these events on its demographic history is poorly understood. Here, we study this question by analysing genetic data from the recently excavated Late Iron Age settlement of Çemialo Sırtı in Batman, southeast Turkey. Archaeological and radiocarbon evidence indicate that the site was inhabited during the second and first millennia BCE. Çemialo Sırtı reveals nomadic items of the Early Iron Age, as well as items associated with the Late Achaemenid and subsequent Hellenistic Periods. We compare Çemialo Sırtı mitochondrial DNA profiles with earlier and later populations from west Eurasia to describe genetic continuity patterns in the region. A total of 16 Çemialo Sırtı in iduals' remains were studied. PCR and Sanger sequencing were used to obtain mitochondrial DNA HVRI-HVRII sequences. We studied haplotype ersity and pairwise genetic distances using F Mitochondrial DNA (mtDNA) haplotypes from 12 Çemialo Sırtı in iduals reveal high haplotype ersity in this population, conspicuously higher than early Holocene west Eurasian populations, which supports the notion of increasing population admixture in west Eurasia through the Holocene. In its mtDNA composition, Çemialo Sırtı shows highest affinity to Neolithic north Syria and Neolithic Anatolia among ancient populations studied, and to modern-day southwest Asian populations. Based on population genetic simulations we cannot reject continuity between Neolithic and Iron Age, or between Iron Age and present-day populations of the region. Despite the region's complex sociopolitical history and indication for increased genetic ersity over time, we find no evidence for sharp shifts in north Mesopotamian maternal genetic composition within the last 10,000 years.
Publisher: University of Chicago Press
Date: 2012
DOI: 10.1086/663202
Abstract: The exact nature of the relationship among species range sizes, speciation, and extinction events is not well understood. The factors that promote larger ranges, such as broad niche widths and high dispersal abilities, could increase the likelihood of encountering new habitats but also prevent local adaptation due to high gene flow. Similarly, low dispersal abilities or narrower niche widths could cause populations to be isolated, but such populations may lack advantageous mutations due to low population sizes. Here we present a large-scale, spatially explicit, in idual-based model addressing the relationships between species ranges, speciation, and extinction. We followed the evolutionary dynamics of hundreds of thousands of diploid in iduals for 200,000 generations. In iduals adapted to multiple resources and formed ecological species in a multidimensional trait space. These species varied in niche widths, and we observed the coexistence of generalists and specialists on a few resources. Our model shows that species ranges correlate with dispersal abilities but do not change with the strength of fitness trade-offs however, high dispersal abilities and low resource utilization costs, which favored broad niche widths, have a strong negative effect on speciation rates. An unexpected result of our model is the strong effect of underlying resource distributions on speciation: in highly fragmented landscapes, speciation rates are reduced.
Publisher: Springer Science and Business Media LLC
Date: 25-05-2014
Publisher: Pensoft Publishers
Date: 07-07-2022
DOI: 10.3897/NEOBIOTA.74.82394
Abstract: CRISPR-based gene drives offer novel solutions for controlling invasive alien species, which could ultimately extend eradication efforts to continental scales. Gene drives for suppressing invasive alien vertebrates are now under development. Using a landscape-scale in idual-based model, we present the first estimates of times to eradication for long-lived alien mammals. We show that demography and life-history traits interact to determine the scalability of gene drives for vertebrate pest eradication. Notably, optimism around eradicating smaller-bodied pests (rodents and rabbits) with gene-drive technologies does not easily translate into eradication of larger-bodied alien species (cats and foxes).
Publisher: Wiley
Date: 17-11-2006
Publisher: Wiley
Date: 28-03-2008
Location: United States of America
No related grants have been discovered for Aysegul Birand.