Transgenerational Epigenetic Inheritance of Pollution Tolerance in Marine Invertebrates Exposed to Chronic Hydrocarbon Contamination in the Niger Delta

Transgenerational epigenetic inheritance represents a theoretically transformative mechanism through which marine invertebrates may acquire heritable pollution tolerance without genetic sequence change, with profound implications for evolutionary ecology in chronically polluted systems. This research investigates the transgenerational transmission of pollution tolerance and associated epigenetic marks in the polychaete Capitella teleta and the oyster Crassostrea gasar collected from Niger Delta contaminated and reference sites, using experimental multigenerational exposure designs. Wild-caught F0 individuals from contaminated and reference sites were bred through three generations (F1, F2, F3) under controlled laboratory conditions. Pollution tolerance was quantified as LC50 values for crude oil WAF. DNA methylation profiling was conducted using whole-genome bisulfite sequencing. Small RNA (piRNA and siRNA) libraries were prepared and sequenced to characterise epigenetic regulatory mechanisms. Chromatin accessibility was assessed using ATAC-seq in F0 through F3 gonads. F1 offspring from contaminated-site F0 parents showed significantly elevated LC50 values compared to reference-site F1 progeny even when reared in clean water, confirming transgenerational tolerance transfer. DNA methylation differences between lineages persisted through F3, predominantly at transposable element regions flanking stress response genes. Differential piRNA abundance in germline tissue corresponded with differential methylation at transposable elements, implicating a piRNA-directed methylation inheritance pathway. Gene expression analysis of F3 individuals revealed sustained upregulation of DNA repair and detoxification pathways. The study provides the first experimental evidence of epigenetically mediated pollution tolerance inheritance in an African marine invertebrate system. Keywords: transgenerational epigenetics, pollution tolerance, Niger Delta, DNA methylation, marine invertebrates.