ArticleProceedings of the National Academy of Sciences of the United States of America2025
Sharks and rays have the oldest vertebrate sex chromosome with unique sex determination mechanisms.
Article in Proceedings of the National Academy of Sciences of the United States of America, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
6 citing papers in PubMed.
- Evolution of an amphibian-specific family of epidermal differentiation-associated genes.Molecular biology and evolution · 2026Article
- The Vertebrate Genomes Project Phase I: A global reference genome resource.bioRxiv : the preprint server for biology · 2026Article
- Silver chimaera genome highlights lineage-specific sex chromosome and opsin gene evolution in holocephalans.DNA research : an international journal for rapid publication of reports on genes and genomes · 2026Article
- Improved genome assembly of whale shark, the world's biggest fish: revealing intragenomic heterogeneity in molecular evolution.GigaScience · 2026Article
- HJ Muller and the Relationship Between Sex Chromosome Degeneration and the Evolution of Dosage Compensation.Genome biology and evolution · 2025Review
- Chromosome-Level Assembly and Annotation of the Grey Reef Shark (Carcharhinus amblyrhynchos) Genome.Genome biology and evolution · 2025Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
13 authors.
Funding
Abstract
Sex determination has been investigated across vertebrate lineages to reveal the stepwise evolution of sex chromosomes and the diversity of responsible molecular mechanisms. However, these studies rarely include cartilaginous fishes, which diverged from the other vertebrates 450 Mya, hindering the comprehensive view of vertebrate sex determination. Here, we produced chromosome-scale genome assemblies of egg-laying shark species and comparatively investigated genome sequences and transcriptome profiles across diverse cartilaginous fishes. Sex chromosome identification, supported by cytogenetic experiments, elucidated the homology of X chromosomes between sharks and rays as well as an extensively degenerated Y chromosome harboring no detectable male-specific genes. Orthologs of documented sex-determining genes were identified, but not on these sex chromosomes. Transcriptomic analyses combined with histology of embryonic gonads revealed female-biased expression of X-linked genes-including those implicated in the TGF-β and IGF signaling pathways-attributed to incomplete dosage compensation. Our findings indicate that sharks and rays share the oldest sex chromosomes among vertebrates that originated around 300 Mya and the dosage-dependent sex determination mechanism composed of distinct molecules from other vertebrates. This study highlights the antiquity of sex chromosomes and the uniqueness of sex determination mechanisms in sharks and rays, which advances our understanding of evolutionary plasticity in vertebrate sex determination.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.