We present genome sequences for the caecilians Geotrypetes seraphini (3.8 Gb) and Microcaecilia unicolor (4.7 Gb), representatives of a limbless, mostly soil-dwelling amphibian clade with reduced eyes, and unique putatively chemosensory tentacles. More than 69% of both genomes are composed of repeats, with retrotransposons being the most abundant. We identify 1,150 orthogroups that are unique to caecilians and enriched for functions in olfaction and detection of chemical signals. There are 379 orthogroups with signatures of positive selection on caecilian lineages with roles in organ development and morphogenesis, sensory perception, and immunity amongst others. We discover that caecilian genomes are missing the zone of polarizing activity regulatorysequence (ZRS) enhancer of Sonic Hedgehog which is also mutated in snakes. In vivo deletions have shown ZRS is required for limb development in mice, thus, revealing a shared molecular target implicated in the independent evolution of limblessness in snakes and caecilians.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10195157 | PMC |
| http://dx.doi.org/10.1093/molbev/msad102 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Convergent Degenerated Regulatory Elements Associated with Limb Loss in Limbless Amphibians and Reptiles.
Mol Biol Evol
November 2024
Shaanxi Key Laboratory of Qinling Ecological Intelligent Monitoring and Protection, School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China.
Article Synopsis
- Limbs are a key feature of tetrapods, but some species, especially amphibians and reptiles, have lost them to adapt to different environments, prompting research into the genetic reasons behind this.
- The study focuses on the Banna caecilian, a limbless amphibian, and compares its genome with other species to identify specific genes related to limb development that have been lost or altered.
- Findings show that both caecilians and snakes have a unique set of conserved genetic elements linked to limb loss, which may play an important role in limb development evolution across tetrapods, providing new insights into how species adapt morphologically over time.
The future of amphibian immunology: Opportunities and challenges.
Dev Comp Immunol
November 2024
Departments of Pathology, Microbiology and Immunology and of Pediatrics, Vanderbilt University School of Medicine and Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA. Electronic address:
Historically, amphibians have been essential to our understanding of vertebrate biology and animal development. Because development from egg to tadpole to adult frog can be directly observed, amphibians contributed greatly to our understanding of not only vertebrate animal development but also the development of the immune system. The South African clawed frog (Xenopus laevis) has been key to many of these findings.
View Article and Find Full Text PDFThe genomic evolution of visual opsin genes in amphibians.
Vision Res
September 2024
Biodiversity Research Center, Academia Sinica, Taipei, Taiwan. Electronic address:
Among tetrapod (terrestrial) vertebrates, amphibians remain more closely tied to an amphibious lifestyle than amniotes, and their visual opsin genes may be adapted to this lifestyle. Previous studies have discussed physiological, morphological, and molecular changes in the evolution of amphibian vision. We predicted the locations of the visual opsin genes, their neighboring genes, and the tuning sites of the visual opsins, in 39 amphibian genomes.
View Article and Find Full Text PDFGenomic SNPs resolve the phylogeny of an ancient amphibian island radiation from the Seychelles.
Mol Phylogenet Evol
September 2024
Natural History Museum, Cromwell Road, London SW7 5BD, UK; Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK.
Unusually for oceanic islands, the granitic Seychelles host multiple lineages of endemic amphibians. This includes an ancient (likely ca. 60 million years) radiation of eight caecilian species, most of which occur on multiple islands.
View Article and Find Full Text PDFDiversity and Molecular Evolution of Antimicrobial Peptides in Caecilian Amphibians.
Toxins (Basel)
March 2024
Department of Biodiversity Ecology and Evolution, Faculty of Biological Sciences, Complutense University of Madrid, 28040 Madrid, Spain.
Antimicrobial peptides (AMPs) are key molecules in the innate immune defence of vertebrates with rapid action, broad antimicrobial spectrum, and ability to evade pathogen resistance mechanisms. To date, amphibians are the major group of vertebrates from which most AMPs have been characterised, but most studies have focused on the bioactive skin secretions of anurans (frogs and toads). In this study, we have analysed the complete genomes and/or transcriptomes of eight species of caecilian amphibians (order Gymnophiona) and characterised the diversity, molecular evolution, and antimicrobial potential of the AMP repertoire of this order of amphibians.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!