Examinando por Autor "Gallardo-Escárate, Cristian"

Mostrando 1 - 2 de 2
  • Miniatura
    Ítem
    Chromosome-Level Genome Assembly of the Blue Mussel Mytilus chilensis Reveals Molecular Signatures Facing the Marine Environment
    (Multidisciplinary Digital Publishing Institute (MDPI), 2023-04) Gallardo-Escárate, Cristian; Valenzuela-Muñoz, Valentina; Nuñez-Acuña, Gustavo; Valenzuela-Miranda, Diego; Tapia, Fabian J.; Yévenes, Marco; Gajardo, Gonzalo; Toro, Jorge E.; Oyarzún, Pablo A.; Arriagada, Gloria; Novoa, Beatriz; Figueras, Antonio; Roberts, Steven; Gerdol, Marco
    The blue mussel Mytilus chilensis is an endemic and key socioeconomic species inhabiting the southern coast of Chile. This bivalve species supports a booming aquaculture industry, which entirely relies on artificially collected seeds from natural beds that are translocated to diverse physical–chemical ocean farming conditions. Furthermore, mussel production is threatened by a broad range of microorganisms, pollution, and environmental stressors that eventually impact its survival and growth. Herein, understanding the genomic basis of the local adaption is pivotal to developing sustainable shellfish aquaculture. We present a high-quality reference genome of M. chilensis, which is the first chromosome-level genome for a Mytilidae member in South America. The assembled genome size was 1.93 Gb, with a contig N50 of 134 Mb. Through Hi-C proximity ligation, 11,868 contigs were clustered, ordered, and assembled into 14 chromosomes in congruence with the karyological evidence. The M. chilensis genome comprises 34,530 genes and 4795 non-coding RNAs. A total of 57% of the genome contains repetitive sequences with predominancy of LTR-retrotransposons and unknown elements. Comparative genome analysis of M. chilensis and M. coruscus was conducted, revealing genic rearrangements distributed into the whole genome. Notably, transposable Steamer-like elements associated with horizontal transmissible cancer were explored in reference genomes, suggesting putative relationships at the chromosome level in Bivalvia. Genome expression analysis was also conducted, showing putative genomic differences between two ecologically different mussel populations. The evidence suggests that local genome adaptation and physiological plasticity can be analyzed to develop sustainable mussel production. The genome of M. chilensis provides pivotal molecular knowledge for the Mytilus complex. © 2023 by the authors.
  • Miniatura
    Ítem
    Identification and expression analysis of two steamer-like retrotransposons in the Chilean blue mussel (Mytilus chilensis)
    (BioMed Central Ltd., 2024-12) Arriagada, Gloria; Quezada, Johan; Merino-Veliz, Nicolas; Avilés, Fernando; Tapia-Cammas, Diana; Gomez, Jorge; Curotto, Daniela; Valdes, Juan A.; Oyarzún, Pablo A.; Gallardo-Escárate, Cristian; Metzger, Michael J.; Alvarez, Marco
    Background: Disseminated neoplasia (DN) is a proliferative cell disorder of the circulatory system of bivalve mollusks. The disease is transmitted between individuals and can also be induced by external chemical agents such as bromodeoxyuridine. In Mya arenaria, we have cloned and characterized an LTR-retrotransposon named Steamer. Steamer mRNA levels and gene copy number correlates with DN and can be used as a marker of the disease. So far, the only mollusk where a retrotransposon expression relates to DN is Mya arenaria. On the other hand, it has been reported that the Chilean blue mussel Mytilus chilensis can also suffers DN. Our aim was to identify retrotransposons in Mytilus chilensis and to study their expression levels in the context of disseminated neoplasia. Results: Here we show that 7.1% of individuals collected in August 2018, from two farming areas, presents morphological characteristics described in DN. Using Steamer sequence to interrogate the transcriptome of M. chilensis we found two putative retrotransposons, named Steamer-like elements (MchSLEs). MchSLEs are present in the genome of M. chilensis and MchSLE1 is indeed an LTR-retrotransposon. Neither expression, nor copy number of the reported MchSLEs correlate with DN status but both are expressed at different levels among individual animals. We also report that in cultured M. chilensis haemocytes MchSLEs1 expression can be induced by bromodeoxyuridine. Conclusions: We conclude that SLEs present in Mytilus chilensis are differentially expressed among individuals and do not correlate with disseminated neoplasia. Treatment of haemocytes with a stressor like bromodeoxyuridine induces expression of MchSLE1 suggesting that in Mytilus chilensis environmental stressors can induce activation of LTR-retrotransposon. © The Author(s) 2024.