The genetic basis and potential molecular mechanism of yellow-albino northern snakehead (Channa argus)

Abstract

Body colour is an important economic trait for commercial fishes. Recently, a new colour morph displaying market-favoured yellow skin (termed as yellow-mutant, YM) of northern snakehead ( Channa argus ) was discovered in China. We confirmed that YM snakehead is an albino with complete loss of melanin in the skin and eyes by histological and ultrastructural observations, and inherited as a recessive Mendelian trait. By applying genomic analysis approaches, in combination with gene knockdown and rescue experiments, we suggested a non-sense mutation in slc45a2 (c.383G > A) is the causation for the YM snakehead. Notably, significantly higher levels of key melanogenesis genes ( tyr , tyrp1 , dct and pmel ) and phospho-MITF protein were detected in YM snakehead than those in wild-type individuals, and the underlying mechanism was further investigated by comparative transcriptomic analysis. Results revealed that differential expressed genes involved in pathways like MAPK, WNT and calcium signalling were significantly induced in YM snakehead, which might account for the increased amount of melanogenesis elements, and presumably be stimulated by fibroblast-derived melanogenic factors in a paracrine manner. Our study clarified the genetic basis of colour variation in C. argus and provided the preliminary clue indicating the potential involvement of fibroblasts in pigmentation in fish.

Klumpy: A Tool to Evaluate the Integrity of Long-Read Genome Assemblies and Illusive Sequence Motifs

“…Furthermore, we were unable to replicate the syntenic region presented by Zhou et al (2022) using Klumpy (Figs S6 and S7; Text S2). Regardless of these findings, a complete adcy5 gene was located in the albino northern snakehead genome, supporting the findings by Sun et al (2023). northern snakehead genome assemblies.…”

“…The adcy5 gene has been previously noted as having a functional role in guppy ( Poecilia reticulata ) pigmentation (Kottler et al 2015), and its putative absence in the albino northern snakehead genome may reflect a similar effect on the organism’s phenotype. Interestingly, an alternative investigation by Sun et al (2023) examined the molecular basis of the albino phenotype in the northern snakehead and proposed a non-sense mutation in the slc45a2 gene as causal. We searched the results of Sun et al (2023) and found no mention of adcy5 or its association with the albino phenotype.…”

“…Interestingly, an alternative investigation by Sun et al (2023) examined the molecular basis of the albino phenotype in the northern snakehead and proposed a non-sense mutation in the slc45a2 gene as causal. We searched the results of Sun et al (2023) and found no mention of adcy5 or its association with the albino phenotype. Motivated by this discrepancy, we sought to apply Klumpy to search for the adcy5 gene or any of its remnants in the albino northern snakehead reference genome to validate its association with the albino phenotype.…”

Snakehead Fish Extract in Increasing Skin Collagen & Fibroblasts

“…Peptide content and antioxidant activity also increased with increasing hydrolysis time. Sun et al (2023) Genomic analysis, gene knockdow n experiment s, and transcripto mic analysis…”

Effects of leucism on organ development and molecular mechanisms in Northern snakehead (Channa argus) beyond pigmentation alterations

“…It serves as a significant method for eliminating the serpent-like appearance, wherein the synthesis of pigments within the organism's body is obstructed, consequently leading to the manifestation of a white, golden-white, or light-golden exterior form 8 . The emergence of the yellowalbino variety may be attributed to the potential involvement of genes associated with pathways such as MAPK, WNT, and calcium signaling, which potentially increase melanogenesis elements and are likely stimulated by fibroblast-derived melanogenic factors 9 . On the other hand, the production of white varieties may be due to the fact that melanin synthesis, WNT, and MAPK signaling pathways are associated with skin depigmentation in C. argus, and the low expression of pigment-related genes contributes to the manifestation of whitening characteristics 10 .…”