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Cairns, K.

Publications and source records attributed to Cairns, K..

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Domestic dog introgression in Australian dingoes: environmental drivers and evolutionary consequences

Introgressive hybridization between wild and domestic animals is a widespread phenomenon with important implications for genetic diversity, local adaptation, and conservation management. The causes and consequences of this process are poorly understood. In Australia, hybridization between dingoes and domestic dogs presents a dual conservation challenge, threatening the genetic integrity of dingoes while allowing potential adaptive introgression. To investigate the environmental drivers of this process, we analyzed high-density SNP array data in 390 dingoes and 396 domestic dogs. Dingo populations showed regional genetic structure and were clearly differentiated from domestic dogs. Using local ancestry inference and genome-environment association analyses, we found low levels of dog introgression in dingoes from remote areas in Central and Western Australia, and moderate levels in Eastern and Southern populations. Climatic variables (maximum temperature of the warmest month, mean temperature of the driest quarter) and the Human Footprint Index (reflecting density of human populations and environmental modifications) were significant predictors of introgression. We identified four genomic regions with overrepresented dog ancestry, including a large introgressed block on chromosome 27, which contained an olfactory receptor gene showing signatures of positive selection, suggesting adaptive introgression. In addition, a chromosomal inversion previously described in dogs and absent in dingoes was initially identified as an introgressed block. We also detected eight genomic regions nearly free of dog ancestry, suggesting purifying selection against maladaptive variants. Together, these results highlight the complex interplay between introgression, human influence, and local adaptation in dingoes, offering valuable insights for conserving the evolutionary potential of this apex predator in increasingly modified landscapes.

evolutionary biology↗

Genomic signatures of bottleneck and founder effects in dingoes

Dingoes arrived in Australia during the mid-Holocene and are the native top-order terrestrial predator on the mainland and some offshore islands. Although dingoes subsequently spread across the continent, the initial founding population(s) could have been small. To investigate this hypothesis, we examined the potential signatures of bottlenecks and founder effects in dingoes by sequencing the whole genomes of three dingoes and also obtaining the genome data from nine additional dingoes and 56 canines, including wolves, village dogs and breed dogs, and examined the signatures of bottlenecks and founder effects. We found that the nucleotide diversity of dingoes was low, and 36% less than highly inbred breed dogs and 3.3 times lower than wolves. The number of runs of homozygosity (RoH) segments in dingoes was 1.6 to 4.7 times higher than in other canines. Whilst examining deleterious mutational load, we observed that dingoes carried elevated ratios of nonsynonymous-to-synonymous diversities, significantly higher numbers of homozygous deleterious Single Nucleotide Variants (SNVs), and increased numbers of loss of function SNVs, compared to breed dogs, village dogs, and wolves. These results suggest dingoes experienced a severe bottleneck, potentially caused by the limited number of founding individuals. While many studies observe less diversity and a higher number of deleterious mutations in domesticated populations compared to their wild relatives, we observed the opposite - .i.e. wild dingoes have lower diversity and a greater number of harmful mutations than domesticated dogs. Our findings can be explained by bottlenecks and founder effects during the establishment of dingoes on mainland Australia. These findings highlight the need for conservation-based management of dingoes and need for wildlife managers to be cognisant of these findings when considering the use of lethal control measures across the landscape.

evolutionary biology↗