Biology subjects

Galia-Camps, C.

Publications and source records attributed to Galia-Camps, C..

3 recordsLinked to original sources

bioRxiv2025

Genomic connectivity and adaptation signals of the freshwater sponge Ephydatia muelleri across its distribution

1.Freshwater sponges fulfill critical ecological functions, including maintaining water quality, regulating nutrient dynamics, offering habitats for diverse taxa, and serving as a vital food source for various species. However, their patterns of dispersal and genetic connectivity remain inadequately understood, posing significant challenges to effective conservation assessments. We examined genetic connectivity and genetic adaptation to local environmental conditions in Ephydatia muelleri across its geographic range using ddRADseq-derived SNPs from 106 individuals collected from 11 localities spanning North America, Europe, and Asia. Analysis of 3,182 neutral SNPs revealed low connectivity and strong genetic structure among regions within two main genetic clusters of North America and Eurasia, while 115 SNPs identified to be under selection showed considerable evidence for differentiated, polygenic adaptation to light and temperature conditions across sampled locations, as well as selection on gene regulatory processes. These findings align with the "monopolization hypothesis", suggesting that historical climatic and geological conditions of the Last Glacial Maximum, including habitat expansion, contraction, and natural barriers, have contributed more to the current genetic structure of E. muelleri populations than contemporary gene flow, which is restricted by monopolistic habitat colonization by this species. Our results provide novel support for ecological theory on dispersal in aquatic invertebrates, as well as insights into the plasticity of E. muelleri in the face of varying environmental conditions that are fundamentally important for freshwater ecosystem conservation.

evolutionary biology↗

bioRxiv2025

ERGA-BGE Reference Genome of Phyllidia flava (Nudibranchia: Phyllidiidae), a Relict Species Endemic to the Mediterranean Sea

Phyllidia flava, the only Mediterranean representative of the otherwise Indo-Pacific family Phyllididae, is a radula-less dorid nudibranch that feeds exclusively on toxic sponges, from which it derives defensive and camouflage compounds. Although not currently listed as endangered, this relict species remains vulnerable due to its restricted distribution and the rising temperatures of the Mediterranean Sea. A total of 13 contiguous chromosomal pseudomolecules were assembled, resulting in a chromosome-level genome spanning 1.9 Gb. This assembly comprises 2,032 contigs and 62 scaffolds, with contig and scaffold N50 values of 2.4 Mb and 169.7 Mb, respectively. This reference genome will serve as a valuable resource for conservation efforts, provide a robust calibration point for studying nudibranch phylogenetics based on the Tethys Ocean closure, and lay the groundwork for research into toxic prey diet specialisation.

genomics↗

bioRxiv2024

Chromosome-level genome assembly of the sacoglossan sea slug Elysia timida (Risso, 1818)

BackgroundSequencing and annotating genomes of non-model organisms helps to understand genome architecture, the genetic processes underlying species traits, and how these genes have evolved in closely-related taxa, among many other biological processes. However, many metazoan groups, such as the extremely diverse molluscs, are still underrepresented in the number of sequenced and annotated genomes. Although sequencing techniques have recently improved in quality and quantity, molluscs are still neglected due to difficulties in applying standardized protocols for obtaining genomic data. ResultsIn this study, we present the chromosome-level genome assembly and annotation of the marine sacoglossan species Elysia timida, known for its ability to store the chloroplasts of its food algae. In particular, by optimizing the Long-read and chromosome conformation capture library preparations, the genome assembly was performed using PacBio HiFi and Arima HiC data. The scaffold and contig N50s, at 41.8 Mb and 1.92 Mb, respectively, are 100-fold and 4-fold higher compared to other published sacoglossan genome assemblies. Structural annotation resulted in 19,904 protein-coding genes, which are more contiguous and complete compared to publicly available annotations of Sacoglossa. We detected genes encoding polyketide synthases in E. timida, indicating that polypropionates are produced. HPLC-MS/MS analysis confirmed the presence of a large number of polypropionates, including known and yet uncharacterised compounds. ConclusionsWe can show that our methodological approach helps to obtain a high-quality genome assembly even for a "difficult-to-sequence" organism, which may facilitate genome sequencing in molluscs. This will enable a better understanding of complex biological processes in molluscs, such as functional kleptoplasty in Sacoglossa, by significantly improving the quality of genome assemblies and annotations.

genomics↗