Temporal variation in DNA methylation during gonadal development in a reptile with temperature-dependent sex determination

Abstract

DNA methylation plays a significant role in transducing external environmental signals to a cellular response in reptiles; however, whether the methylation patterns are conserved across species remains unclear. Here, we examined the genome-wide DNA methylation differentiation between male and female hatchling gonads of the temperature-dependent sex determination (TSD) Mauremys mutica (M. mutica) using methylation-dependent restriction-site associated DNA sequencing (MethylRAD-seq) to test differentially methylated genes underlying sexual development. Several categories, including heat shock genes (HSP90A, HSP30C), histone- (KDM8) and ubiquitin-related genes (TRIM39), kinases (WNK3) and gonad differentiation or gonadal development related genes (HSD17B8, HSD17B12), were identified as candidates for future study. Additionally, we identified several regulatory pathways potentially mediating TSD thermosensitivity such as the GnRH signaling pathway and calcium signaling pathway. These findings provide evidence that sexually dimorphic DNA methylation may be associated with sex determination or sex differentiation in TSD M. mutica.

Screening of temperature-responsive signalling molecules during sex differentiation in Asian yellow pond turtle (Mauremys mutica)

“…3). Moreover, genes involved in steroid hormone biosynthesis have been identi ed as key factors in regulating sex differentiation in turtles and sh [22,31]. Interestingly, we screened Nr4a1, Hsd17b5, Hsd17b6 and Itga6 from the DEGs in the Asian yellow pond turtle.…”

“…Although important progress has been made in the study of temperature-dependent sex determination mechanisms in T. scripta, the control of gonadal sex determination is remarkably diverse [12], so it is of great importance to generalise the research objects by identifying more upstream sex-determining genes, studying their position in the hierarchical network of sex control, and constructing a cascade system to regulate sex development. Recently, we generated a high-quality genome assembly of the Asian yellow pond turtle based on continuous long read (PacBio platform), Illumina and high-throughput chromatin conformation capture (Hi-C) technologies [21], and then screened several sex-speci c markers using multi-omics conjoint analysis [17,22]. However, we know much less about the overall temporal pattern of sex-speci c genes responding to temperature.…”

Screening of temperature-responsive signalling molecules during sex differentiation in Asian yellow pond turtle (Mauremys mutica)

“…A high-quality genome assembly of the Asian yellow pond turtle was recently generated using continuous long read (PacBio platform), Illumina and high-throughput chromatin conformation capture (Hi-C) technologies [ 25 ]. Subsequently, several sex-specific markers were screened using multi-omics conjoint analysis [ 18 , 26 ]. However, the overall temporal pattern of sex-specific genes responding to temperature remains poorly understood.…”