Annelid Comparative Genomics and the Evolution of Massive Lineage-Specific Genome Rearrangement in Bilaterians
Research article published in Molecular biology and evolution (2024)
Abstract
The organization of genomes into chromosomes is critical for processes such as genetic recombination, environmental adaptation, and speciation. All animals with bilateral symmetry inherited a genome structure from their last common ancestor that has been highly conserved in some taxa but seemingly unconstrained in others. However, the evolutionary forces driving these differences and the processes by which they emerge have remained largely uncharacterized. Here, we analyze genome organization across the phylum Annelida using 23 chromosome-level annelid genomes. We find that while many annelid lineages have maintained the conserved bilaterian genome structure, the Clitellata, a group containing leeches and earthworms, possesses completely scrambled genomes. We develop a rearrangement index to quantify the extent of genome structure evolution and show that, compared to the last common ancestor of bilaterians, leeches and earthworms have among the most highly rearranged genomes of any currently sampled species. We further show that bilaterian genomes can be classified into two distinct categories-high and low rearrangement-largely influenced by the presence or absence, respectively, of chromosome fission events. Our findings demonstrate that animal genome structure can be highly variable within a phylum and reveal that genome rearrangement can occur both in a gradual, stepwise fashion, or rapid, all-encompassing changes over short evolutionary timescales.
Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.
Resumen
The organization of genomes into chromosomes is critical for processes such as genetic recombination, environmental adaptation, and speciation.
Por qué esto importa para la hirudoterapia
Este estudio genómico comparativo analizó la organización del genoma a nivel cromosómico en el filo Annelida utilizando 23 genomas, encontrando que Clitellata (sanguijuelas y lombrices de tierra) posee genomas altamente reordenados en comparación con la estructura ancestral conservada de los bilaterales. Los autores desarrollaron un índice de reordenamiento que muestra que los genomas de sanguijuela y lombriz de tierra se encuentran entre los más reordenados muestreados, clasificables en categorías de alto y bajo reordenamiento impulsadas en gran medida por eventos de fisión cromosómica. Para ASH, este estudio tiene solo la relevancia más tangencial: comprender la arquitectura del genoma de la sanguijuela podría teóricamente respaldar la investigación genómica futura sobre compuestos salivales, pero el resumen no reporta nada sobre anticoagulantes, el secretoma de la sanguijuela, hirudoterapia ni ninguna aplicación terapéutica. Se trata de un estudio de estructura genómica y biología evolutiva sin conexión directa con el dominio de interés de ASH.
Citación
Annelid Comparative Genomics and the Evolution of Massive Lineage-Specific Genome Rearrangement in Bilaterians
Lewin TD et al. · Molecular biology and evolution, 2024
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Añadido a la biblioteca ASH: May 27, 2026 · Última actualización del sitio: 18 de junio de 2026