Epigenetics and conservation of small populations: microevolution and adaptive divergence in relict bear populations
ProgettoThe project investigated the biological mechanisms that have enabled the relict population of the Apennine brown bear to survive over time, despite its small size, marked isolation, and high level of inbreeding. In particular, it explored the role of genetic variation, epigenetic regulation, and gene expression in processes of survival and adaptation in heavily human-modified environments.
The project integrated genomic, epigenomic, and transcriptomic data to understand the adaptive processes of the Marsican bear. The main objectives were to identify the distinctive genetic features of the population, detect fixed variants (SNPs) and assess their possible functional role, also in relation to DNA methylation, and to analyse blood transcriptomes by RNA-seq in order to investigate links with adaptation, physiology, and susceptibility to disease.
The expected outcome was a clearer picture of the molecular pathways involved in the adaptation of the Apennine bear compared with other European populations. The integration of genetic, epigenetic, and transcriptomic data was intended to provide an initial framework for understanding the mechanisms underlying the long-term persistence of the species.
Genomic analyses on 44 individuals confirmed that Apennine bears show the lowest level of heterozygosity among the populations examined, consistent with strong genetic drift following a demographic bottleneck. More than 21,000 SNPs were identified, many of them located within CpG islands (CpGi) and defined by us as methyl-SNPs, and absent from the other European populations; these were associated with genes involved in neurodevelopment, cognition, morphogenesis, metabolism, epigenetic regulation, and immune response.
These findings are consistent with known traits of the Apennine bear, such as smaller body size and reduced aggressiveness, and indicate convergence between genetic and epigenetic patterns in adaptive processes. Despite the low genetic diversity, the DNA methylation results suggest that this population may still retain substantial adaptive evolutionary potential. At the same time, RNA-seq analysis was successfully initiated on 29 blood samples, and the final results are currently under analysis.
Overall, by combining genomic, epigenetic, and transcriptomic approaches, the study has laid solid foundations for a new and important perspective on the biology of the Apennine bear, showing that even a small and highly inbred population can persist and adapt over the long term, while also responding to possible future environmental and conservation challenges.
The project integrated genomic, epigenomic, and transcriptomic data to understand the adaptive processes of the Marsican bear. The main objectives were to identify the distinctive genetic features of the population, detect fixed variants (SNPs) and assess their possible functional role, also in relation to DNA methylation, and to analyse blood transcriptomes by RNA-seq in order to investigate links with adaptation, physiology, and susceptibility to disease.
The expected outcome was a clearer picture of the molecular pathways involved in the adaptation of the Apennine bear compared with other European populations. The integration of genetic, epigenetic, and transcriptomic data was intended to provide an initial framework for understanding the mechanisms underlying the long-term persistence of the species.
Genomic analyses on 44 individuals confirmed that Apennine bears show the lowest level of heterozygosity among the populations examined, consistent with strong genetic drift following a demographic bottleneck. More than 21,000 SNPs were identified, many of them located within CpG islands (CpGi) and defined by us as methyl-SNPs, and absent from the other European populations; these were associated with genes involved in neurodevelopment, cognition, morphogenesis, metabolism, epigenetic regulation, and immune response.
These findings are consistent with known traits of the Apennine bear, such as smaller body size and reduced aggressiveness, and indicate convergence between genetic and epigenetic patterns in adaptive processes. Despite the low genetic diversity, the DNA methylation results suggest that this population may still retain substantial adaptive evolutionary potential. At the same time, RNA-seq analysis was successfully initiated on 29 blood samples, and the final results are currently under analysis.
Overall, by combining genomic, epigenetic, and transcriptomic approaches, the study has laid solid foundations for a new and important perspective on the biology of the Apennine bear, showing that even a small and highly inbred population can persist and adapt over the long term, while also responding to possible future environmental and conservation challenges.