scholarly journals Neocortex expansion is linked to size variations in gene families with chemotaxis, cell–cell signalling and immune response functions in mammals

Open Biology ◽  
2016 ◽  
Vol 6 (10) ◽  
pp. 160132
Author(s):  
Atahualpa Castillo-Morales ◽  
Jimena Monzón-Sandoval ◽  
Alexandra A. de Sousa ◽  
Araxi O. Urrutia ◽  
Humberto Gutierrez
Keyword(s):  
Immune Response ◽  
Adult Development ◽  
Brain Size ◽  
Mammalian Species ◽  
Cell Signalling ◽  
Relative Size ◽  
Brain Evolution ◽  
Gene Families ◽  
Evolutionary Innovation ◽  
Cell Cell

Increased brain size is thought to have played an important role in the evolution of mammals and is a highly variable trait across lineages. Variations in brain size are closely linked to corresponding variations in the size of the neocortex, a distinct mammalian evolutionary innovation. The genomic features that explain and/or accompany variations in the relative size of the neocortex remain unknown. By comparing the genomes of 28 mammalian species, we show that neocortical expansion relative to the rest of the brain is associated with variations in gene family size (GFS) of gene families that are significantly enriched in biological functions associated with chemotaxis, cell–cell signalling and immune response. Importantly, we find that previously reported GFS variations associated with increased brain size are largely accounted for by the stronger link between neocortex expansion and variations in the size of gene families. Moreover, genes within these families are more prominently expressed in the human neocortex during early compared with adult development. These results suggest that changes in GFS underlie morphological adaptations during brain evolution in mammalian lineages.

scholarly journals Increased brain size in mammals is associated with size variations in gene families with cell signalling, chemotaxis and immune-related functions

2014 ◽  
Vol 281 (1775) ◽  
pp. 20132428 ◽  
Author(s):  
Atahualpa Castillo-Morales ◽  
Jimena Monzón-Sandoval ◽  
Araxi O. Urrutia ◽  
Humberto Gutiérrez
Keyword(s):  
Brain Size ◽  
Mammalian Species ◽  
Cell Signalling ◽  
Gene Families ◽  
Comparative Approach ◽  
Functional Requirements ◽  
Genome Wide ◽  
A Genome ◽  
Evolutionary Response ◽  
Highly Correlated

Genomic determinants underlying increased encephalization across mammalian lineages are unknown. Whole genome comparisons have revealed large and frequent changes in the size of gene families, and it has been proposed that these variations could play a major role in shaping morphological and physiological differences among species. Using a genome-wide comparative approach, we examined changes in gene family size (GFS) and degree of encephalization in 39 fully sequenced mammalian species and found a significant over-representation of GFS variations in line with increased encephalization in mammals. We found that this relationship is not accounted for by known correlates of brain size such as maximum lifespan or body size and is not explained by phylogenetic relatedness. Genes involved in chemotaxis, immune regulation and cell signalling-related functions are significantly over-represented among those gene families most highly correlated with encephalization. Genes within these families are prominently expressed in the human brain, particularly the cortex, and organized in co-expression modules that display distinct temporal patterns of expression in the developing cortex. Our results suggest that changes in GFS associated with encephalization represent an evolutionary response to the specific functional requirements underlying increased brain size in mammals.

scholarly journals Quantitative genetic analysis of brain size variation in sticklebacks: support for the mosaic model of brain evolution

2015 ◽  
Vol 282 (1810) ◽  
pp. 20151008 ◽  
Author(s):  
Kristina Noreikiene ◽  
Gábor Herczeg ◽  
Abigél Gonda ◽  
Gergely Balázs ◽  
Arild Husby ◽  
...  
Keyword(s):  
Body Size ◽  
Brain Size ◽  
Additive Genetic Variance ◽  
Genetic Correlations ◽  
Relative Size ◽  
Strong Support ◽  
Brain Evolution ◽  
Brain Regions ◽  
Independent Evolution ◽  
Mosaic Model

The mosaic model of brain evolution postulates that different brain regions are relatively free to evolve independently from each other. Such independent evolution is possible only if genetic correlations among the different brain regions are less than unity. We estimated heritabilities, evolvabilities and genetic correlations of relative size of the brain, and its different regions in the three-spined stickleback ( Gasterosteus aculeatus ). We found that heritabilities were low (average h 2 = 0.24), suggesting a large plastic component to brain architecture. However, evolvabilities of different brain parts were moderate, suggesting the presence of additive genetic variance to sustain a response to selection in the long term. Genetic correlations among different brain regions were low (average r G = 0.40) and significantly less than unity. These results, along with those from analyses of phenotypic and genetic integration, indicate a high degree of independence between different brain regions, suggesting that responses to selection are unlikely to be severely constrained by genetic and phenotypic correlations. Hence, the results give strong support for the mosaic model of brain evolution. However, the genetic correlation between brain and body size was high ( r G = 0.89), suggesting a constraint for independent evolution of brain and body size in sticklebacks.

scholarly journals Evolution of the T-Cell Receptor (TR) Loci in the Adaptive Immune Response: The Tale of the TRG Locus in Mammals

Genes ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 624 ◽  
Author(s):  
Rachele Antonacci ◽  
Serafina Massari ◽  
Giovanna Linguiti ◽  
Anna Caputi Jambrenghi ◽  
Francesco Giannico ◽  
...  
Keyword(s):  
Immune Response ◽  
Genomic Organization ◽  
Mammalian Species ◽  
Adaptive Immune Response ◽  
Gene Families ◽  
Cell Receptor ◽  
Gene Organization ◽  
Cell Mediated Immunity ◽  
Gene Repertoire ◽  
Trg Locus

T lymphocytes are the principal actors of vertebrates’ cell-mediated immunity. Like B cells, they can recognize an unlimited number of foreign molecules through their antigen-specific heterodimer receptors (TRs), which consist of αβ or γδ chains. The diversity of the TRs is mainly due to the unique organization of the genes encoding the α, β, γ, and δ chains. For each chain, multi-gene families are arranged in a TR locus, and their expression is guaranteed by the somatic recombination process. A great plasticity of the gene organization within the TR loci exists among species. Marked structural differences affect the TR γ (TRG) locus. The recent sequencing of multiple whole genome provides an opportunity to examine the TR gene repertoire in a systematic and consistent fashion. In this review, we report the most recent findings on the genomic organization of TRG loci in mammalian species in order to show differences and similarities. The comparison revealed remarkable diversification of both the genomic organization and gene repertoire across species, but also unexpected evolutionary conservation, which highlights the important role of the T cells in the immune response.

Predation impacts brain allometry and offspring production in female guppies (Poecilia reticulata)

2021 ◽  
Author(s):  
Regina Vega-Trejo ◽  
David Joseph Mitchell ◽  
Catarina Vila Pouca ◽  
Alexander Kotrschal
Keyword(s):  
Poecilia Reticulata ◽  
Brain Size ◽  
Relative Size ◽  
Reproductive Traits ◽  
Brain Evolution ◽  
Predation Pressure ◽  
Control Fish ◽  
Brain Anatomy ◽  
Offspring Production ◽  
The Impact

Survivorship under predation exerts strong selection on reproductive traits as well as on brain anatomy of prey. However, how exactly predation and brain evolution are linked has not been resolved as current empirical evidence is inconclusive. This may be due to predation pressure having different effects across life stages and/or due to confounding factors in ecological comparisons of predation pressure. Here, we used adult guppies (Poecilia reticulata) to experimentally test the impact of a period of strong predation on brain anatomy and reproduction of surviving individuals. We compared the survivors to control fish, which were exposed to visual and olfactory predator cues but could not be predated on, and found that predation impacted the relative size of female brains. This effect was dependent on body size as larger female survivors showed relatively larger brains, while smaller survivors showed relatively smaller brains when compared to control animals. There were no differences in male relative brain size between the treatments, nor for any specific relative brain region sizes for either sex. Moreover, survivors produced more offspring, but did not show shorter interbrood intervals than controls. Our results corroborate the important, yet complex, role of predation as an important factor behind variation in brain anatomy.

How cells tell up from down and stick together to construct multicellular tissues – interplay between apicobasal polarity and cell–cell adhesion

2021 ◽  
Vol 134 (21) ◽  
Author(s):  
Claudia G. Vasquez ◽  
Eva L. de la Serna ◽  
Alexander R. Dunn
Keyword(s):  
Cell Adhesion ◽  
Protein Complexes ◽  
Basic Function ◽  
Cell Junction ◽  
Evolutionary Innovation ◽  
Apicobasal Polarity ◽  
Complex Architectures ◽  
Main Components ◽  
Definition Of ◽  
Cell Cell

ABSTRACT Polarized epithelia define a topological inside and outside, and hence constitute a key evolutionary innovation that enabled the construction of complex multicellular animal life. Over time, this basic function has been elaborated upon to yield the complex architectures of many of the organs that make up the human body. The two processes necessary to yield a polarized epithelium, namely regulated adhesion between cells and the definition of the apicobasal (top–bottom) axis, have likewise undergone extensive evolutionary elaboration, resulting in multiple sophisticated protein complexes that contribute to both functions. Understanding how these components function in combination to yield the basic architecture of a polarized cell–cell junction remains a major challenge. In this Review, we introduce the main components of apicobasal polarity and cell–cell adhesion complexes, and outline what is known about their regulation and assembly in epithelia. In addition, we highlight studies that investigate the interdependence between these two networks. We conclude with an overview of strategies to address the largest and arguably most fundamental unresolved question in the field, namely how a polarized junction arises as the sum of its molecular parts.

Complexity of the cell–cell interactions in the innate immune response after cerebral ischemia

2015 ◽  
Vol 1623 ◽  
pp. 53-62 ◽  
Author(s):  
María I. Cuartero ◽  
Iván Ballesteros ◽  
Ignacio Lizasoain ◽  
María A. Moro
Keyword(s):  
Immune Response ◽  
Cerebral Ischemia ◽  
Innate Immune Response ◽  
Innate Immune ◽  
Cell Interactions ◽  
Cell Cell

scholarly journals Cell–cell signalling: Frog frizbees

1997 ◽  
Vol 7 (8) ◽  
pp. R501-R504 ◽  
Author(s):  
Aaron M Zorn
Keyword(s):  
Cell Signalling ◽  
Cell Cell
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