Abstract
The utilization of complete mitochondrial (mt) genomes as molecular markers for exploring phylogenetic relationships is increasingly prevalent. Here, we conducted sequencing of the complete mt genome of Fasciola gigantica from 16 samples sourced from cattle, sheep, and goats in Sudan, employing the Illumina MiSeq platform. The resultant mt genome of F. gigantica measured 14,483 bp in length, presenting a circular configuration and comprising 36 genes, including 12 protein-coding genes, 2 subunit ribosomal RNA genes (rRNA), and 22 transfer RNA genes (tRNA). Notably, the start and stop codons of the 12 protein-coding genes were consistently ATG and TAG, respectively, matching reference mt genomes, with the exception of the ND5 gene's start codon (GTG) and the ND4 gene's stop codon (TAA). While the lengths of ten protein-coding genes remained identical between the reference and Sudan isolates, variations were observed in ND4L and COX1. Specifically, the ND4L gene in the reference was 12 bp longer, measuring 273 bp compared to the Sudan isolates, which were 261 bp long. Conversely, COX1 in the reference was 9 bp shorter, measuring 1,533 bp, in contrast to the Sudan isolates, which were 1,542 bp long. These discrepancies highlight specific genomic differences between the reference and Sudan isolates of Fasciola gigantica, potentially indicative of evolutionary divergence or genetic adaptation within distinct populations. Evaluation of non-coding region lengths further revealed disparities between Sudan isolates and the reference. Sliding window analysis unveiled notable nucleotide variability within the mt genome of F. gigantica from Sudan compared to the reference. Phylogenetic analysis, based on concatenated amino acid sequences of all 12 protein-coding genes, depicted distinct clustering of F. gigantica from Sudan. Noteworthy insights into the evolutionary process affecting host specificity, particularly in sheep and goats, were gleaned from stem-loop analysis of non-coding regions. In conclusion, the novel complete mt genomes of F. gigantica from diverse host species serve as valuable genetic markers for investigating epidemiology, population genetics, phylogeography, and host-species interactions. .