scholarly journals Genome-enabled discovery of evolutionary divergence in brains and behavior

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chinar Patil ◽  
Jonathan B. Sylvester ◽  
Kawther Abdilleh ◽  
Michael W. Norsworthy ◽  
Karen Pottin ◽  
...  

AbstractLake Malawi cichlid fishes exhibit extensive divergence in form and function built from a relatively small number of genetic changes. We compared the genomes of rock- and sand-dwelling species and asked which genetic variants differed among the groups. We found that 96% of differentiated variants reside in non-coding sequence but these non-coding diverged variants are evolutionarily conserved. Genome regions near differentiated variants are enriched for craniofacial, neural and behavioral categories. Following leads from genome sequence, we used rock- vs. sand-species and their hybrids to (i) delineate the push–pull roles of BMP signaling and irx1b in the specification of forebrain territories during gastrulation and (ii) reveal striking context-dependent brain gene expression during adult social behavior. Our results demonstrate how divergent genome sequences can predict differences in key evolutionary traits. We highlight the promise of evolutionary reverse genetics—the inference of phenotypic divergence from unbiased genome sequencing and then empirical validation in natural populations.

2021 ◽  
Author(s):  
Chinar Patil ◽  
Jonathan Sylvester ◽  
Kawther Abdilleh ◽  
Michael W. Norsworthy ◽  
Karen Pottin ◽  
...  

Abstract Lake Malawi cichlid fishes exhibit extensive divergence in form and function built from a relatively small number of genetic changes. We compared the genomes of rock- and sand-dwelling species and asked which genetic variants differed among the groups. We found that 96% of differentiated variants reside in non-coding sequence but these non-coding diverged variants are evolutionarily conserved. Genome regions near differentiated variants are enriched for craniofacial, neural and behavioral categories. Following leads from genome sequence, we used rock- vs. sand- species and their hybrids to (i) delineate the push-pull roles of BMP signaling and irx1b in the specification of forebrain territories during gastrulation and (ii) reveal striking context-dependent brain gene expression during adult social behavior. Our results demonstrate how divergent genome sequences can predict differences in key evolutionary traits. We highlight the promise of evolutionary reverse genetics – the inference of divergence in phenotype from genome sequencing in natural populations.


2020 ◽  
Author(s):  
Chinar Patil ◽  
Jonathan B. Sylvester ◽  
Kawther Abdilleh ◽  
Michael W. Norsworthy ◽  
Karen Pottin ◽  
...  

AbstractLake Malawi cichlid fishes exhibit extensive divergence in form and function among closely related species separated by a relatively small number of genetic changes. During the past million years, hundreds of species have diversified along an ecological axis in rock vs. sand habitats. We compared the genomes of rock- and sand-dwelling species and asked which genetic variants in which genes differed among the groups. We found that 96% of differentiated variants reside in non-coding sequence but these non-coding diverged variants are evolutionarily conserved. The majority of divergent coding variants are missense and/or loss of function. Regions near differentiated variants are enriched for craniofacial, neural and behavioral functional categories. To follow up experimentally, we used rock- vs. sand-species and their hybrids to (i) clarify the push-pull roles of BMP signaling and irx1b in the specification of forebrain territories during gastrulation and (ii) reveal striking context-dependent brain gene expression during adult social behavior. Our results suggest compelling ties between early brain development and adult behavior and highlight the promise of evolutionary reverse genetics – the identification of functional variants from genome sequencing in natural populations.


2001 ◽  
Vol 79 (4) ◽  
pp. 297-302 ◽  
Author(s):  
R Boonstra ◽  
L Galea ◽  
S Matthews ◽  
J M Wojtowicz

The dogma that the adult brain produces no new neurons has been overturned, but the critics are still asking, so what? Is adult neurogenesis a biologically relevant phenomenon, or is it perhaps harmful because it disrupts the existing neuronal circuitry? Considering that the phenomenon is evolutionarily conserved in all mammalian species examined to date and that its relevance has been well documented in non-mammalian species, it seems self-evident that neurogenesis in adult mammals must have a role. In birds, it has been established that neurogenesis varies dramatically with seasonal changes in song production. In chickadees, the learning behaviour related to finding stored food is also correlated with seasonal adult neurogenesis. Such studies are still nonexistent in mammals, but the related evidence suggests that neurogenesis does vary seasonally in hamsters and shows sexual differences in meadow voles. To promote studies on natural populations asking fundamental questions of the purpose and function of neurogenesis, we organized a Workshop on "Hippocampal Neurogenesis in Natural Populations" in Toronto in May 2000. The Workshop highlighted recent discoveries in neurogenesis from the lab, and focused on its functional consequences. The consensus at the Workshop was that demonstration of a role for neurogenesis in natural behaviours will ultimately be essential if we are to understand the purpose and function of neurogenesis in humans.Key words: neurogenesis, hippocampus, dentate gyrus, learning, memory, wild population.


2014 ◽  
Vol 92 (12) ◽  
pp. 989-995 ◽  
Author(s):  
Nathan V. Whelan ◽  
Ellen E. Strong

Life histories, including anatomy and behavior, are a critically understudied component of gastropod biology, especially for imperiled freshwater species of Pleuroceridae. This aspect of their biology provides important insights into understanding how evolution has shaped optimal reproductive success and is critical for informing management and conservation strategies. One particularly understudied facet is seasonal variation in reproductive form and function. For example, some have hypothesized that females store sperm over winter or longer, but no study has explored seasonal variation in accessory reproductive anatomy. We examined the gross anatomy and fine structure of female accessory reproductive structures (pallial oviduct, ovipositor) of four species in two genera (round rocksnail, Leptoxis ampla (Anthony, 1855); smooth hornsnail, Pleurocera prasinata (Conrad, 1834); skirted hornsnail, Pleurocera pyrenella (Conrad, 1834); silty hornsnail, Pleurocera canaliculata (Say, 1821)). Histological analyses show that despite lacking a seminal receptacle, females of these species are capable of storing orientated sperm in their spermatophore bursa. Additionally, we found that they undergo conspicuous seasonal atrophy of the pallial oviduct outside the reproductive season, and there is no evidence that they overwinter sperm. The reallocation of resources primarily to somatic functions outside of the egg-laying season is likely an adaptation that increases survival chances during winter months.


2017 ◽  
Author(s):  
Nicholas P. Boyer ◽  
Caroline Monkiewicz ◽  
Sheryl S. Moy ◽  
Stephanie L. Gupton

ABSTRACTSpecific class I members of the TRIM family of E3 ubiquitin ligases have been implicated in neuronal development from invertebrates to mammals. The single invertebrate class I TRIM and mammalian TRIM9 regulate axon branching and guidance in response to the axon guidance cue netrin-1, whereas mammalian TRIM46 establishes the axon initial segment. In humans, mutations in TRIM1 and TRIM18 are implicated in Optiz Syndrome, characterized by midline defects and often mild intellectual disability. TRIM67 is the most evolutionarily conserved vertebrate class I TRIM, yet is the least studied. Here we show that TRIM67 interacts with both its closest paralog TRIM9 and the netrin receptor DCC, and is differentially enriched in specific brain regions at specific developmental points. We describe the anatomical and behavioral consequences of deletion of murine Trim67. While viable, mice lacking Trim67 display severe impairments in spatial memory, cognitive flexibility, social novelty preference, muscle function and sensorimotor gating. Additionally, they exhibit abnormal anatomy of several brain regions, including the hippocampus, striatum and thalamus, as well as the corpus callosum. This study demonstrates the necessity for TRIM67 in appropriate brain development and function.SIGNIFICANCE STATEMENTAs a family, class I TRIM E3 ubiquitin ligases play important roles in neuronal development and function, potentially cooperatively. TRIM67 is the most evolutionarily conserved class I TRIM and is developmentally regulated and brain-enriched. Deletion of murine Trim67 results in malformations of a subset subcortical brain regions and of cortical and subcortical myelinated fiber tracts, as well as deficits in spatial memory, motor function, sociability and sensorimotor gating. We conclude that TRIM67 is critical for appropriate brain development and behavior, potentially downstream of the axon guidance cue netrin, and in cooperation with class I TRIM9.


2020 ◽  
Vol 3 (12) ◽  
pp. e202000879
Author(s):  
David S Guttery ◽  
Rajan Pandey ◽  
David JP Ferguson ◽  
Richard J Wall ◽  
Declan Brady ◽  
...  

Cells use fatty acids (FAs) for membrane biosynthesis, energy storage, and the generation of signaling molecules. 3-hydroxyacyl-CoA dehydratase—DEH—is a key component of very long chain fatty acid synthesis. Here, we further characterized in-depth the location and function of DEH, applying in silico analysis, live cell imaging, reverse genetics, and ultrastructure analysis using the mouse malaria model Plasmodium berghei. DEH is evolutionarily conserved across eukaryotes, with a single DEH in Plasmodium spp. and up to three orthologs in the other eukaryotes studied. DEH-GFP live-cell imaging showed strong GFP fluorescence throughout the life-cycle, with areas of localized expression in the cytoplasm and a circular ring pattern around the nucleus that colocalized with ER markers. Δdeh mutants showed a small but significant reduction in oocyst size compared with WT controls from day 10 postinfection onwards, and endomitotic cell division and sporogony were completely ablated, blocking parasite transmission from mosquito to vertebrate host. Ultrastructure analysis confirmed degeneration of Δdeh oocysts, and a complete lack of sporozoite budding. Overall, DEH is evolutionarily conserved, localizes to the ER, and plays a crucial role in sporogony.


Author(s):  
Donatella Farini ◽  
Daniela Marazziti ◽  
Maria Concetta Geloso ◽  
Claudio Sette

AbstractIn the past two decades, mounting evidence has modified the classical view of the cerebellum as a brain region specifically involved in the modulation of motor functions. Indeed, clinical studies and engineered mouse models have highlighted cerebellar circuits implicated in cognitive functions and behavior. Furthermore, it is now clear that insults occurring in specific time windows of cerebellar development can affect cognitive performance later in life and are associated with neurological syndromes, such as Autism Spectrum Disorder. Despite its almost homogenous cytoarchitecture, how cerebellar circuits form and function is not completely elucidated yet. Notably, the apparently simple neuronal organization of the cerebellum, in which Purkinje cells represent the only output, hides an elevated functional diversity even within the same neuronal population. Such complexity is the result of the integration of intrinsic morphogenetic programs and extracellular cues from the surrounding environment, which impact on the regulation of the transcriptome of cerebellar neurons. In this review, we briefly summarize key features of the development and structure of the cerebellum before focusing on the pathways involved in the acquisition of the cerebellar neuron identity. We focus on gene expression and mRNA processing programs, including mRNA methylation, trafficking and splicing, that are set in motion during cerebellar development and participate to its physiology. These programs are likely to add new layers of complexity and versatility that are fundamental for the adaptability of cerebellar neurons.


2020 ◽  
Author(s):  
David S. Guttery ◽  
Rajan Pandey ◽  
David J. P. Ferguson ◽  
Richard J. Wall ◽  
Declan Brady ◽  
...  

AbstractCells use fatty acids (FAs) for membrane biosynthesis, energy storage and the generation of signaling molecules. 3-hydroxyacyl-CoA dehydratase – DEH – is a key component of very long chain FA (VLCFA) synthesis. Here, we further characterized in-depth the location and function of DEH, applying in silico analysis, live cell imaging, reverse genetics and ultrastructure analysis using the mouse malaria model Plasmodium berghei. DEH is evolutionarily conserved across eukaryotes, with a single DEH in Plasmodium spp. and up to three orthologs in the other eukaryotes studied. DEH-GFP live-cell imaging showed strong GFP fluorescence throughout the life-cycle, with areas of localized expression in the cytoplasm and a circular ring pattern around the nucleus that colocalized with ER markers. Δdeh mutants showed a small but significant reduction in oocyst size compared to WT controls from day 10 post-infection onwards and endomitotic cell division and sporogony were completely ablated, blocking parasite transmission from mosquito to vertebrate host. Ultrastructure analysis confirmed degeneration of Δdeh oocysts, and a complete lack of sporozoite budding. Overall, DEH is evolutionarily conserved, localizes to the ER and plays a crucial role in sporogony.


2013 ◽  
Vol 368 (1632) ◽  
pp. 20130025 ◽  
Author(s):  
John A. Capra ◽  
Genevieve D. Erwin ◽  
Gabriel McKinsey ◽  
John L. R. Rubenstein ◽  
Katherine S. Pollard

The genetic changes underlying the dramatic differences in form and function between humans and other primates are largely unknown, although it is clear that gene regulatory changes play an important role. To identify regulatory sequences with potentially human-specific functions, we and others used comparative genomics to find non-coding regions conserved across mammals that have acquired many sequence changes in humans since divergence from chimpanzees. These regions are good candidates for performing human-specific regulatory functions. Here, we analysed the DNA sequence, evolutionary history, histone modifications, chromatin state and transcription factor (TF) binding sites of a combined set of 2649 non-coding human accelerated regions (ncHARs) and predicted that at least 30% of them function as developmental enhancers. We prioritized the predicted ncHAR enhancers using analysis of TF binding site gain and loss, along with the functional annotations and expression patterns of nearby genes. We then tested both the human and chimpanzee sequence for 29 ncHARs in transgenic mice, and found 24 novel developmental enhancers active in both species, 17 of which had very consistent patterns of activity in specific embryonic tissues. Of these ncHAR enhancers, five drove expression patterns suggestive of different activity for the human and chimpanzee sequence at embryonic day 11.5. The changes to human non-coding DNA in these ncHAR enhancers may modify the complex patterns of gene expression necessary for proper development in a human-specific manner and are thus promising candidates for understanding the genetic basis of human-specific biology.


2021 ◽  
Author(s):  
Meng-Jia Lau ◽  
Tom Schmidt ◽  
Qiong Yang ◽  
Jessica Chung ◽  
Lucien Sankey ◽  
...  

Abstract BackgroundWolbachia wMel is the most used strain in mosquito rear and release strategies that aim to inhibit the transmission of arboviruses such as dengue, Zika, Chikungunya and yellow fever. However, the long-term establishment of wMel in natural populations of the dengue mosquito Aedes aegypti raises concerns that interactions between Wolbachia wMel and Ae. aegypti may lead to changes in the host genome, which could affect useful attributes of Wolbachia that allow it to invade and suppress disease transmission. ResultsWe applied an evolve-and-resequence approach to study genome-wide genetic changes in Ae. aegypti from the Cairns region, Australia, where Wolbachia wMel was first introduced more than 10 years ago. Mosquito samples were collected at three different time points in Gordonvale, Australia, covering the phase before (2010) and after (2013 and 2018) Wolbachia releases. An additional three locations where Wolbachia replacement happened at different times across the last decade were also sampled in 2018. We found that the genomes of mosquito populations mostly remained stable after Wolbachia release, with population differences tending to reflect the geographic location of the populations rather than Wolbachia infection status. However, outlier analysis suggests that Wolbachia may have had an influence on some genes related to immune response, development, recognition and behavior. ConclusionsAe. aegypti populations remained geographically distinct after Wolbachia wMel releases in North Australia despite their Wolbachia infection status. At some specific genomic loci, we found signs of selection associated with Wolbachia, suggesting potential evolutionary impacts can happen in the future and further monitoring is warranted.


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