Extraembryonic gut endoderm cells undergo programmed cell death during development.

Despite a distinct developmental origin, extraembryonic cells in mice contribute to gut endoderm and converge to transcriptionally resemble their embryonic counterparts. Notably, all extraembryonic progenitors share a non-canonical epigenome, raising several pertinent questions, including whether this landscape is reset to match the embryonic regulation and if extraembryonic cells persist into later development. Here we developed a two-colour lineage-tracing strategy to track and isolate extraembryonic cells over time. We find that extraembryonic gut cells display substantial memory of their developmental origin including retention of the original DNA methylation landscape and resulting transcriptional signatures. Furthermore, we show that extraembryonic gut cells undergo programmed cell death and neighbouring embryonic cells clear their remnants via non-professional phagocytosis. By midgestation, we no longer detect extraembryonic cells in the wild-type gut, whereas they persist and differentiate further in p53-mutant embryos. Our study provides key insights into the molecular and developmental fate of extraembryonic cells inside the embryo.

Reconstructing axial progenitor field dynamics in mouse stem cell-derived embryoids.

Embryogenesis requires substantial coordination to translate genetic programs to the collective behavior of differentiating cells, but understanding how cellular decisions control tissue morphology remains conceptually and technically challenging. Here, we combine continuous Cas9-based molecular recording with a mouse embryonic stem cell-based model of the embryonic trunk to build single-cell phylogenies that describe the behavior of transient, multipotent neuro-mesodermal progenitors (NMPs) as they commit into neural and somitic cell types. We find that NMPs show subtle transcriptional signatures related to their recent differentiation and contribute to downstream lineages through a surprisingly broad distribution of individual fate outcomes. Although decision-making can be heavily influenced by environmental cues to induce morphological phenotypes, axial progenitors intrinsically mature over developmental time to favor the neural lineage. Using these data, we present an experimental and analytical framework for exploring the non-homeostatic dynamics of transient progenitor populations as they shape complex tissues during critical developmental windows.

Comparative topographical description of the central nervous system of the macaw (Ara ararauna) and the owl (Tyto furcata)Comparative Topographical Description of the Central Nervous System of the Macaw (Ara ararauna) and the Owl (Tyto furcata) / Descripción topográfica comparativa del sistema nervioso central del guacamayo (Ara ararauna) y el búho (Tyto furcata)

SUMMARY: The study of animal neurology has historically focused on the closest descendants of humans, such as monkeys and chimpanzees. Because of this, the neurology of birds remains poorly studied and understood by humans compared to other groups of animals. Thus, the objective was to describe the central nervous system to better understand its functioning, correlating the findings with the role it plays in the physiology and biology of birds, comparing species with different behaviors between herbivores and carnivores, filling gaps in the literature serving as subsidy for future research.

RESUMEN: El estudio de la neurología animal se ha centrado históricamente en los descendientes más cercanos de los humanos, como los monos y los chimpancés. Debido a esto, la neurología de las aves sigue siendo poco estudiada y comprendida, en comparación con la de otros grupos de animales. Así, el objetivo fue describir el sistema nervioso central para comprender mejor su funcionamiento, correlacionando los hallazgos con el rol que juega en la fisiología y biología de las aves, comparando especies con diferentes comportamientos entre herbívoros y carnívoros y llenando vacíos en la literatura que sirvan como base para futuras investigaciones.

Comparative Topographical Description of the Central Nervous System of the Macaw (Ara ararauna) and the Owl (Tyto furcata)

SUMMARY: The study of animal neurology has historically focused on the closest descendants of humans, such as monkeys and chimpanzees. Because of this, the neurology of birds remains poorly studied and understood by humans compared to other groups of animals. Thus, the objective was to describe the central nervous system to better understand its functioning, correlating the findings with the role it plays in the physiology and biology of birds, comparing species with different behaviors between herbivores and carnivores, filling gaps in the literature serving as subsidy for future research.

El estudio de la neurología animal se ha centrado históricamente en los descendientes más cercanos de los humanos, como los monos y los chimpancés. Debido a esto, la neurología de las aves sigue siendo poco estudiada y comprendida, en comparación con la de otros grupos de animales. Así, el objetivo fue describir el sistema nervioso central para comprender mejor su funcionamiento, correlacionando los hallazgos con el rol que juega en la fisiología y biología de las aves, comparando especies con diferentes comportamientos entre herbívoros y carnívoros y llenando vacíos en la literatura que sirvan como base para futuras investigaciones.