Biology subjects

Sunnucks, P.

Publications and source records attributed to Sunnucks, P..

3 recordsLinked to original sources

bioRxiv2026

Designing meta-population genetic management for a small, endangered passerine with fragmented range

ContextGenetic diversity is essential for the persistence and future adaptation of species. However, human-driven habitat fragmentation results in population isolation, often leading to rapid loss of genetic diversity and adaptive capacity. Genetic management of focal taxa may be overlooked in many threatened species conservation programs. The Endangered southeastern Australian mallee emu-wren Stipiturus mallee is a species that may benefit from genetic management. Its current range encompasses patchily distributed sub-populations, prone to bottlenecks and genetic drift. Thus, the reintroduction to areas from which the species has been locally extirpated requires careful selection of founders to maximise genetic diversity. AimsWe analyse reduced-representation genomic data from seven sampling areas across the global meta-population to design a translocation strategy that maximises heterozygosity and retention of mallee emu-wren allelic diversity. MethodsWe estimated genetic structure, genetic diversity within, and differentiation between subpopulations, thus testing previous inference based on 12 length-variable loci of low population differentiation with 10,840 genome-wide SNP loci. We also estimated effective population sizes to identify populations in need of genetic augmentation, Finally, we used metapop2 simulations to estimate the relative contributions of each population to global genetic diversity of the species and to estimate the source and number of founders that would maximise heterozygosity and allelic richness in a hypothetical newly established population. Key resultsWe found weak genetic structure across all sampling areas, supporting previous conclusions that the global mallee emu-wren population should be considered a single genetic unit for management purposes. Low but significant Weir and Cockerham pairwise FST among locations indicated differentiation between sampling areas, suggesting that contemporary gene flow is restricted. Effective population sizes for the two regions supporting the largest numbers of mallee emu-wrens were below the threshold associated with reduced adaptive potential. ConclusionsThe genetic health and adaptive potential of sampled mallee emu-wren sub-populations are at risk. Implications The global mallee emu-wren meta-population would likely benefit from genetic augmentation, including reciprocal gene flow between extant sub-populations. To maximise genetic diversity in newly established populations, managers should prioritise gene-pool mixing with founders sourced from all sampled areas.

genetics↗

bioRxiv2025

Genetic load proxies do not predict fitness better than inbreeding does in a wild population

A key goal in conservation is managing endangered populations in order to maximise individual and population fitness. Genetic management that reduces inbreeding and increases genetic diversity has been consistently successful, but recent attention has been drawn to managing genetic load instead. We investigated whether genetic load proxies based on evolutionary conservation predict individual fitness better than inbreeding does. We re-sequenced the genomes of 43 wild helmeted honeyeaters with lifetime fitness data, and 28 individuals of other subspecies. None of the 28 genetic load proxies we tested predicted lifetime reproductive success better than three inbreeding metrics did, and different load proxies were inconsistent regarding the occurrence of purging or accumulation of deleterious alleles. Genetic load proxies need further validation as fitness indicators for conservation management.

genomics↗

bioRxiv2016

Mitochondrial-nuclear interactions maintain a deep mitochondrial split in the face of nuclear gene flow

Metabolic processes in eukaryotic cells depend on interactions between mitochondrial and nuclear gene products (mitonuclear interactions). These interactions could play a direct role in population divergence. We studied the evolution of mitonuclear interactions in a widespread passerine that experienced population divergence followed by bi-directional mitochondrial introgression into different nuclear backgrounds. Using >60,000 SNPs, we quantified patterns of nuclear genetic differentiation between populations that occupy different climates and harbour deeply divergent mitolineages despite ongoing nuclear gene flow. Analyses were performed independently for two sampling transects intersecting mitochondrial divergence in different nuclear backgrounds. In both transects, low genome-wide nuclear differentiation was accompanied by strong differentiation at a ~15.4 Mb region of chromosome 1A. This region is enriched for genes performing mitochondrial functions. Molecular signatures of selective sweeps in this region alongside those in the mitochondrial genome suggest a history of adaptive mitonuclear co-introgression. The chromosome 1A region has elevated linkage disequilibrium, suggesting that selection on genomic architecture may favour low recombination among nuclear-encoded genes with mitochondrial functions. In this system, mitonuclear interactions appear to maintain the geographic separation of two mitolineages in the face of nuclear gene flow, supporting mitonuclear co-evolution as an important vehicle for climatic adaptation and population divergence.

evolutionary biology↗