Pascual, F. | bioRxiv Science

bioRxiv2025

Genomic Analysis Reveals Recent Population Decline and Exceptionally Low Genome-Wide Heterozygosity of the Critically Endangered Philippine Eagle, Pithecophaga jefferyi (Aves: Accipitridae)

The Philippine Eagle (Pithecophaga jefferyi), is one of the rarest eagles in the world and is the national bird of the Philippines. It is listed by the International Union for Conservation of Nature (IUCN) as a critically endangered raptor and has been the subject of an intensive captive breeding program which started more than 30 years ago to ensure the survival and conservation of the species. To infer the genetic diversity and demographic history of the Philippine Eagle, we sequenced and analyzed the genomes of 35 individuals under the captive breeding program of the Philippine Eagle Foundation. Phylogenetic analysis of the draft reference sequence generated in this study placed P. jefferyi within the subfamily Circaetinae of Accipitridae. Demographic history reconstruction from genome-wide variants revealed two historical bottlenecks, as well as an ongoing population decline which was found to predate documented deforestation in the Philippines. This observation suggests that unobserved natural or anthropogenic factors might have severely affected the Philippine Eagle population long before habitat fragmentation. Genome-wide heterozygosity estimates placed the Philippine Eagle as having one of the lowest genome-wide heterozygosity levels measured among raptors. This highlights the precarious genetic state of the Philippine Eagle, as critically low heterozygosity raises risks of inbreeding depression, reduced reproductive success, and increased vulnerability to diseases, climate change, and habitat loss. The genomic resources generated in this study can therefore guide conservation strategies such as breeding program design, genetic monitoring, and other efforts to diversify existing populations to ensure both demographic stability and genetic resilience of the Philippine Eagle. Subject AreasPhilippine Eagle, Genomics, Genome-wide heterozygosity, Demographic History, Conservation, Biodiversity, Bioinformatics

genomics↗

bioRxiv2020

Cardiomyocyte-specific ACSL1 Deficiency Prevents Cardiac Lipotoxicity and Alleviates Heart Dysfunction in the ob/ob Model of Obesity

Cardiac lipotoxicity is associated with structural remodeling and functional changes that are features of obesity-related cardiomyopathy. Both high fat diet and the ob/ob mutation lead to increased fatty acid (FA) uptake, elevated triacylglycerol (TAG) content, hypertrophy, and systolic and diastolic dysfunction in murine hearts. Cardiomyocyte-specific long-chain acyl-CoA synthetase 1 (ACSL1) deficiency (Acsl1H-/-) results in a 90% reduction in FA activation, suggesting that Acsl1 ablation might alleviate obesity-associated myocardial dysfunction. Double knockout ob-Acsl1H-/- and ob-Acsl1flox/flox control mice were treated with tamoxifen at 20 weeks of age; heart function, TAG content, and relevant gene expression were assessed immediately before and 2 and 5 weeks after treatment. Heart weights initially increased in lean and obese Acsl1H-/- mice, but normalized in ob-Acsl1H-/- mice by 5 weeks. Ventricular TAG content was decreased by 51% and 61% in ob-Acsl1H-/- mice 2 and 5 weeks after Acsl1 knockout induction, respectively. Moreover, ACSL1 knockout resulted in increased survival of ob/ob mice, suggesting that lack of ACSL1 protected obese hearts subjected to stress. Our results indicate that partial knockdown of cardiac ACSL1 is sufficient to reverse cardiac TAG accumulation and to ameliorate heart dysfunction even in the context of established obesity-related cardiomyopathy.

physiology↗