Salamanders serve as important tetrapod models for developmental, regeneration and evolutionary studies. An extensive molecular toolkit makes the Mexican axolotl (Ambystoma mexicanum) a key representative salamander for molecular investigations. Here we report the sequencing and assembly of the 32-gigabase-pair axolotl genome using an approach that combined long-read sequencing, optical mapping and development of a new genome assembler (MARVEL). We observed a size expansion of introns and intergenic regions, largely attributable to multiplication of long terminal repeat retroelements. We provide evidence that intron size in developmental genes is under constraint and that species-restricted genes may contribute to limb regeneration. The axolotl genome assembly does not contain the essential developmental gene Pax3. However, mutation of the axolotl Pax3 paralogue Pax7 resulted in an axolotl phenotype that was similar to those seen in Pax3 −/− and Pax7 −/− mutant mice. The axolotl genome provides a rich biological resource for developmental and evolutionary studies.

Vertebrates harbor recognizably orthologous gene complements but vary 100-fold in genome size. How chromosomal organization scales with genome expansion is unclear, and how acute changes in gene regulation, as during axolotl limb regeneration, occur in the context of a vast genome has remained a riddle. Here, we describe the chromosome-scale assembly of the giant, 32 Gb axolotl genome. Hi-C contact data revealed the scaling properties of interphase and mitotic chromosome organization. Analysis of the assembly yielded understanding of the evolution of large, syntenic multigene clusters, including the Major Histocompatibility Complex (MHC) and the functional regulatory landscape of the Fibroblast Growth Factor 8 (Axfgf8) region. The axolotl serves as a primary model for studying successful regeneration.

The axolotl (Ambystoma mexicanum) is the vertebrate model system with the highest regeneration capacity. Experimental tools established over the past 100 years have been fundamental to start unraveling the cellular and molecular basis of tissue and limb regeneration. In the absence of a reference genome for the Axolotl, transcriptomic analysis become fundamental to understand the genetic basis of regeneration. Here we present one of the most diverse transcriptomic data sets for Axolotl by profiling coding and non-coding RNAs from diverse tissues. We reconstructed a population of 115,906 putative protein coding mRNAs as full ORFs (including isoforms). We also identified 352 conserved miRNAs and 297 novel putative mature miRNAs. Systematic enrichment analysis of gene expression allowed us to identify tissue-specific protein-coding transcripts. We also found putative novel and conserved microRNAs which potentially target mRNAs which are reported as important disease candidates in heart and liver.

O artigo analisa a separação entre a história cultural e a história da educação. Examinando obras a partir dos anos de 1970, verifica a importância crescente da história cultural e a ausência quase completa de trabalhos relativos à história cultural da educação. Aborda questões disciplinares e institucionais, mas também historiográficas, que concorrem para a exclusão de determinadas disciplinas, como a história da educação, do âmbito de trabalho do historiador. Durante a década de 1980, detecta maior interesse pela história da educação e por sua inserção nas perspectivas historiográficas. Focaliza algumas questões que interessam aos historiadores e aos historiadores da educação: as relações entre história e cultura; a tentativa de considerar a história cultural em duas perspectivas: uma que lhe atribui o recorte e análise de objetos culturais, e outra que privilegia os pressupostos metodológicos, abordando tanto as práticas sociais como as suas representações, de acordo com concepções das diversas teorias sociais. Conclui que a história cultural é um campo multi ou interdisciplinar, não apenas um tipo de abordagem, nem apenas um novo espaço ou dimensão do real, e enfatiza a necessidade de uma reflexão mais sistemática sobre a educação como um tema/objeto de investigação necessário à compreensão da formação cultural de uma sociedade.