Prenatal development of skull and brain in a mouse model of growth restriction

Abstract

Patterns of covariation result from the overlapping effect of several developmental processes. By perturbing certain specific developmental processes, experimental studies contribute to a better understanding of their particular effects on the generation of phenotype. The aim of this work was to analyze the interactions among morphological traits of the skull and the brain during late prenatal life (18.5 days postconception) in mice exposed to maternal protein undernutrition. Images from the skull and brain were obtained through micro-computed tomography and 3D landmark coordinates were digitized in order to quantify shape and size of both structures with geometric morphometric techniques. The results highlight a systemic effect of protein restriction on the size of the skull and the brain, which were both significantly reduced in the undernourished group compared to control group. Skull shape Key woRdS maternal protein restriction; phenotypic integration; cranial modules; micro-CT is partially explained by brain size, and patterns of shape variation were only partially coincident with previous reports for other ontogenetic stages, suggesting that allometric trajectories across pre-and postnatal ages change their directions. Within the skull, neurocranial and facial shape traits covaried strongly, while subtle covariation was found between the shape of the skull and the brain. These findings are in line with former studies in mutant mice and reveal the importance of carrying out analyses of phenotypic variation in a broad range of developmental stages. The present study contributes to the basic understanding of epigenetic relations among growing tissues and has direct implications for the field of paleoanthropology, where inferences about brain morphology are usually derived from skull remains. Rev Arg Antrop Biol 18 (1) PAlABRAS ClAve restricción proteica materna; integración fenotípica; módulos craneanos; micro-TC ReSUMeN Los patrones de covariación entre rasgos fenotí-picos resultan de la acción de diversos procesos que se solapan durante el desarrollo. Los estudios experimentales constituyen la aproximación más adecuada para evaluar el efecto de procesos específicos en la generación de tales patrones. El objetivo de este trabajo es analizar las interacciones entre rasgos morfológicos craneofaciales y cerebrales durante la vida prenatal tardía (18,5 días posconcepción) en ratones expuestos a desnutrición proteica materna. Se obtuvieron imá-genes del cráneo y cerebro a partir de microtomografía computada y se digitalizaron landmarks en 3D para cuantificar la forma y tamaño con técnicas de morfometría geométrica. Los resultados subrayan un efecto sistémico de la restricción proteica en el tamaño del cráneo y el cerebro. La forma del cráneo es parcialmente explicable por el tamaño cerebral y los patrones de variación en forma fueron sólo en parte coincidentes con los reportados antes para otras edades, lo cual sugiere que las trayectorias alométricas a lo largo de la vida pre-y posnatal cambian su direc...

Chronic Protein Restriction in Mice Impacts Placental Function and Maternal Body Weight before Fetal Growth

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Fluctuations in Evolutionary Integration Allow for Big Brains and Disparate Faces

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Why the short face? Developmental disintegration of the neurocranium drives convergent evolution in neotropical electric fishes

“…The skull was a key innovation in the evolution of vertebrates and is a popular model for the study of modularity. The skull has been re-adapted in almost every major vertebrate lineage and performs a wide range of functions, including protecting the brain and special sense organs, and as structural support and muscle attachment sites for tissues involved in respiration, feeding, and communication behaviors of the oral jaws and pharynx (Barbeito-Andrés, Gonzalez, & Hallgrímsson, 2016;Hanken & Hall, 1993a, 1993b. Within the skull, two developmentally distinct modules have been identified: the face and braincase (Marroig et al, 2009;Piras et al, 2014;Porto, Shirai, Oliveira, & Marroig, 2013;Sanger, Mahler, Abzhanov, & Losos, 2012;Tokita, Kiyoshi, & Armstrong, 2007).…”