Biology subjects

Munoz-Merida, A.

Publications and source records attributed to Munoz-Merida, A..

3 recordsLinked to original sources

bioRxiv2026

Cartilaginous fish inform the lineage-specific evolution and MHC association of the TLR family

Chondrichthyans (sharks, rays and chimaeras) diverged from other vertebrate lineages over 400 million years ago and possess fully functional innate and adaptive immune systems. They comprise over 1,200 species occupying diverse aquatic habitats, from fresh to marine waters and from shallow to deep seas. Exposure to diverse pathogens through time, together with contemporary ocean warming and habitat degradation driven by climate change, has likely shaped unique immune mechanisms in these species. Toll-like receptors (TLRs) are central components of innate immunity, recognizing conserved pathogen-associated molecular patterns and initiating immune responses, yet their diversity remains poorly characterized in Chondrichthyans. Here, we characterize the TLR gene repertoire in elasmobranchs (sharks and rays) using genomic and transcriptomic data. We identify orthologs spanning all known vertebrate TLR families, including genes shared with agnathans as well as gnathostome-specific genes, and detect lineage-specific patterns of TLR duplication and loss, particularly in squaliform sharks and rays. Molecular evolution analyses indicate that most elasmobranch TLRs are under strong purifying selection, with positively selected sites in all genes, consistent with ongoing adaptation to pathogen-and environment-driven pressures. Several TLRs co-localize with genomic regions enriched in immune genes, including MHC paralogous regions, suggesting an ancestral genomic hotspot for vertebrate immunity.

evolutionary biology↗

bioRxiv2023

MIMt: A curated 16S rRNA reference database with less redundancy and higher accuracy at species-level identification

MotivationAccurate determination and quantification of the taxonomic composition of microbial communities, especially at the species level, is one of the major issues in metagenomics. This is primarily due to the limitations of commonly used 16S rRNA reference databases, which either contain a lot of redundancy, or a high percentage of sequences with missing taxonomic information. The use of these incomplete or biased databases may lead to erroneous identifications and, thus, to erroneous conclusions regarding the ecological role and importance of those microorganisms in the ecosystem. ResultsThe current study presents MIMt, a new 16S rRNA database for archaea and bacterias identification, encompassing 39 940 sequences, all precisely identified at species level. MIMt aims to be updated at least once a year to include all new sequenced species. We evaluated MIMt against Greengenes, RDP, GTDB and SILVA in terms of sequence distribution and accuracy of taxonomic assignments. Our results showed that MIMt contains less redundancy, and despite being five to 85 times smaller in size than existing databases, outperforms them in completeness and taxonomic accuracy, enabling more precise assignments at lower taxonomic ranks and thus, significantly improving species-level identification. Availability and ImplementationMIMt is freely available for non-commercial purposes at https://mimt.bu.biopolis.pt

microbiology↗

bioRxiv2021

Evidence of post-domestication hybridization and adaptive introgression in Western European grapevine varieties

Grapevine (Vitis vinifera L.) is one of the most significant crops in the world. Todays richness in grapevine diversity results from a complex domestication history over multiple historical periods. Here, we employed whole genome resequencing to elucidate different aspects of the recent evolutionary history of this crop. Our results support a model in which a central domestication event in grapevine was followed by post-domestication hybridization with local wild genotypes, leading to the presence of an introgression signature in modern wine varieties across Western Europe. The strongest signal was associated with a subset of Iberian grapevine varieties, which show large introgression tracts. We targeted this study group for further analysis, demonstrating how regions under selection in wild populations from the Iberian Peninsula were preferentially passed on to the cultivated varieties by geneflow. Examination of underlying genes suggests that environmental adaptation played a fundamental role in both the evolution of wild genotypes and the outcome of hybridization with cultivated varieties, supporting a case of adaptive introgression in grapevine.

plant biology↗