miR-430 microRNA Family in Fishes: Molecular Characterization and Evolution Jiménez-Ruiz, Claudio Amador Herrán Moreno, Roberto De La Robles Rodríguez, Francisca Navajas Pérez, Rafael Cross, Ismael Rebordinos, Laureana Ruiz Rejón, Carmelo Noncoding RNA Tandem repeats Genomic organization This research was funded by the Spanish Ministry of Economy and Competitiveness, FEDER, grant number RTI2018-096847-B-C22, and Regional Government of Andalusia—FEDER Grant: P20-00938. The miR-430 microRNA family has been described in multiple fish species as one of the first microRNAs expressed by the zygote. It has been suggested that this family is implicated in maternal mRNA elimination, but may also play a role in steroidogenesis, sexual differentiation, and flatfish metamorphosis. The miR-430 sequences have been found in multiple-copy tandem clusters but evidence of their conservation outside of teleost fishes is scarce. In the present study, we have characterized the tandem repeats organization of these microRNAs in different fish species, both model and of interest in aquaculture. A phylogenetic analysis of this family has allowed us to identify that the miR-430 duplication, which took place before the Chondrostei and Neopterygii groups’ divergence, has resulted in three variants (“a”, “b”, and “c”). According to our data, variant “b” is the most closely related to the ancestral sequence. Furthermore, we have detected isolated instances of the miR-430 repeat subunit in some species, which suggests that this microRNA family may be affected by DNA rearrangements. This study provides new data about the abundance, variability, and organization of the miR-430 family in fishes. 2024-01-19T08:16:17Z 2024-01-19T08:16:17Z 2023 journal article Jiménez-Ruiz, C.A.; de la Herrán, R.; Robles, F.; Navajas-Pérez, R.; Cross, I.; Rebordinos, L.; Ruiz-Rejón, C. miR-430 microRNA Family in Fishes: Molecular Characterization and Evolution. Animals 2023, 13, 2399. https://doi.org/10.3390/ani13152399 https://hdl.handle.net/10481/86934 10.3390/ani13152399 eng http://creativecommons.org/licenses/by/3.0/ open access Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License MDPI