scholarly journals Non-linear phenotypic variation uncovers the emergence of heterosis inArabidopsis thaliana

2018 ◽  
Author(s):  
François Vasseur ◽  
Louise Fouqueau ◽  
Dominique de Vienne ◽  
Thibault Nidelet ◽  
Cyrille Violle ◽  
...  
Keyword(s):  
Phenotypic Variation ◽  
Evolutionary Biology ◽  
Molecular Mechanisms ◽  
Intrinsic Property ◽  
Geometric Approach ◽  
Crop Productivity ◽  
Plant Performance ◽  
Allometric Relationships ◽  
Non Linear ◽  
Additive Inheritance

AbstractHeterosis describes the phenotypic superiority of hybrids over their parents in traits related to fitness. Understanding and predicting non-additive inheritance such as heterosis is crucial for evolutionary biology, as well as for plant and animal breeding. However, the physiological bases of heterosis remain debated. Moreover, empirical data in various species have shown that diverse genetic and molecular mechanisms are likely to explain heterosis, making it difficult to predict its emergence and amplitude from parental genotypes alone. In this study, we evaluated a model of physiological dominance proposed by Sewall Wright to explain the non-additive inheritance of metabolic fluxes at the cellular level. We used 450 hybrids derived from crosses among natural inbred accessions ofArabidopsis thalianato test Wright’s model for two fitness-related traits at the whole-plant level: growth rate and fruit number. We found that allometric relationships between traits constrain phenotypic variation in hybrids and inbreds to a similar extent. These allometric relationships behave predictably, in a non-linear manner, explaining up to 75% of heterosis amplitude, while genetic distance among parents at best explains 7%. Thus, our findings are consistent with Wright’s model of physiological dominance on plant performance, and suggest that the emergence of heterosis is an intrinsic property of non-linear relationships between traits. Furthermore, our study highlights the potential of a geometric approach of phenotypic relationships for predicting heterosis of two major components of crop productivity and yield.

scholarly journals The Critical Role of Zinc in Plants Facing the Drought Stress

Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 396
Author(s):  
Muhammad Umair Hassan ◽  
Muhammad Aamer ◽  
Muhammad Umer Chattha ◽  
Tang Haiying ◽  
Babar Shahzad ◽  
...  
Keyword(s):  
Drought Stress ◽  
Molecular Mechanisms ◽  
Stress Proteins ◽  
Critical Role ◽  
Crop Productivity ◽  
Plant Performance ◽  
Future Research ◽  
Cell Membrane Stability ◽  
Crop Resistance

Drought stress affects plant growth and development by altering physiological and biochemical processes resulting in reduced crop productivity. Zinc (Zn) is an essential micronutrient that plays fundamental roles in crop resistance against the drought stress by regulating various physiological and molecular mechanisms. Under drought stress, Zn application improves seed germination, plant water relations, cell membrane stability, osmolyte accumulation, stomatal regulation, water use efficiency and photosynthesis, thus resulting in significantly better plant performance. Moreover, Zn interacts with plant hormones, increases the expression of stress proteins and stimulates the antioxidant enzymes for counteracting drought effects. To better appraise the potential benefits arising from optimum Zn nutrition, in the present review we discuss the role of Zn in plants under drought stress. Our aim is to provide a complete, updated picture in order to orientate future research directions on this topic.

Evolution of stickleback spines through independent cis-regulatory changes at HOXDB

2021 ◽  
Author(s):  
Julia I Wucherpfennig ◽  
Timothy R Howes ◽  
Jessica N Au ◽  
Eric H Au ◽  
Garrett A Roberts Kingman ◽  
...  
Keyword(s):  
Gene Expression ◽  
Evolutionary Biology ◽  
Gasterosteus Aculeatus ◽  
Molecular Mechanisms ◽  
Wild Populations ◽  
Gene Variation ◽  
Regulatory Changes ◽  
Fundamental Goal ◽  
Apeltes Quadracus ◽  
Genetic Mechanisms

Understanding the genetic mechanisms leading to new traits is a fundamental goal of evolutionary biology. We show that HOXDB regulatory changes have been used repeatedly in different stickleback fish species to alter the length and number of bony dorsal spines. In Gasterosteus aculeatus, a variant HOXDB allele is genetically linked to shortening an existing spine and adding a spine. In Apeltes quadracus, a variant allele is associated with lengthening an existing spine and adding a spine. The alleles alter the same conserved non-coding HOXDB enhancer by diverse molecular mechanisms, including SNPs, deletions, and transposable element insertions. The independent cis-acting regulatory changes are linked to anterior expansion or contraction of HOXDB expression. Our findings support the long-standing hypothesis that natural Hox gene variation underlies key morphological patterning changes in wild populations and illustrate how different mutational mechanisms affecting the same region may produce opposite gene expression changes with similar phenotypic outcomes.

scholarly journals Molecular mechanisms governing circulating immune cell heterogeneity across different species revealed by single cell sequencing

2021 ◽  
Author(s):  
Zhibin Li ◽  
chengcheng Sun ◽  
Fei Wang ◽  
Xiran Wang ◽  
Jiacheng Zhu ◽  
...  
Keyword(s):  
Single Cell ◽  
Immune Cells ◽  
Evolutionary Biology ◽  
Regulatory Networks ◽  
Molecular Mechanisms ◽  
Mononuclear Cells ◽  
Immune Cell ◽  
Cell Types ◽  
Genetic Regulatory Networks ◽  
Peripheral Blood Mononuclear

Background: Immune cells play important roles in mediating immune response and host defense against invading pathogens. However, insights into the molecular mechanisms governing circulating immune cell diversity among multiple species are limited. Methods: In this study, we compared the single-cell transcriptomes of 77 957 immune cells from 12 species using single-cell RNA-sequencing (scRNA-seq). Distinct molecular profiles were characterized for different immune cell types, including T cells, B cells, natural killer cells, monocytes, and dendritic cells. Results: The results revealed the heterogeneity and compositions of circulating immune cells among 12 different species. Additionally, we explored the conserved and divergent cellular cross-talks and genetic regulatory networks among vertebrate immune cells. Notably, the ligand and receptor pair VIM-CD44 was highly conserved among the immune cells. Conclusions: This study is the first to provide a comprehensive analysis of the cross-species single-cell atlas for peripheral blood mononuclear cells (PBMCs). This research should advance our understanding of the cellular taxonomy and fundamental functions of PBMCs, with important implications in evolutionary biology, developmental biology, and immune system disorders

scholarly journals A simple index to quantify and compare the magnitude of intraspecific geographic plumage colour variation in typical antbirds (Aves: Passeriformes: Thamnophilidae)

2020 ◽  
Vol 130 (2) ◽  
pp. 239-246
Author(s):  
Rafael S Marcondes ◽  
Robb T Brumfield
Keyword(s):  
Geographic Variation ◽  
Phenotypic Variation ◽  
Evolutionary Biology ◽  
Phylogeographic Structure ◽  
Plumage Colour ◽  
Colour Space ◽  
Colour Variation ◽  
Simple Index ◽  
High Prevalence ◽  
Variable Species

Abstract Intraspecific geographic phenotypic variation is a crucial theme in evolutionary biology. Comparing its magnitude across species can provide insights into its ecological and genetic correlates. Here, we developed an index, which we dub the V index, to quantify intraspecific plumage colour variation in typical antbirds (Thamnophilidae), a family which has long interested ornithologists due to a high prevalence of intraspecific variation. The V index is based on a bivariate colour space defined by brightness and redness. Its value for each species equals the mean area occupied by each of its subspecies in that colour space, divided by the area of the species. Lower values indicate greater intraspecific geographic variation. Based on this index, Thamnophilus caerulescens (Variable Antshrike) was exceptionally geographically variable compared to other thamnophilids, as previously suggested based on qualitative evidence. In general, we found that the most variable species had disjunct distributions and deep phylogeographic structure, suggesting an effect of historical population dynamics in producing geographic variation. The V index can be adapted for use with other taxa, traits, and taxonomic levels, and we expect it will instigate novel ways of thinking about phenotypic variation in birds and other animals.

scholarly journals Mortierella elongata Increases Plant Biomass among Non-Leguminous Crop Species

Agronomy ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 754 ◽  
Author(s):  
Kaile Zhang ◽  
Gregory Bonito ◽  
Chih-Ming Hsu ◽  
Khalid Hameed ◽  
Rytas Vilgalys ◽  
...  
Keyword(s):  
Glycine Max ◽  
Leaf Area ◽  
Plant Height ◽  
Molecular Mechanisms ◽  
Plant Biomass ◽  
Citrullus Lanatus ◽  
Plant Performance ◽  
Future Research ◽  
Crop Species ◽  
Leguminous Crop

Recent studies have shown that M. elongata (M. elongata) isolated from Populus field sites has a dual endophyte–saprotroph lifestyle and is able to promote the growth of Populus. However, little is known about the host fidelity of M. elongata and whether M. elongata strains differ from one another in their ability to promote plant growth. Here, we compared the impacts of three Populus-associated M. elongata isolates (PMI 77, PMI 93, and PMI 624) on the growth of seven different crop species by measuring plant height, plant dry biomass, and leaf area. M. elongata isolates PMI 624 and PMI 93 increased the plant height, leaf area, and plant dry weight of Citrullus lanatus, Zea mays, Solanum lycopersicum, and Cucurbita to a much greater degree than PMI 77 (33.9% to 14.1%). No significant impacts were observed for any isolate on the growth of Abelmoschus esculentus or Glycine max. On the contrary, Glycine max significantly decreased in height by 30.6% after the inoculation of M. elongata PMI 77. In conclusion, this study demonstrates that M. elongata generally promoted metrics of the plant performance among a diverse set of importantly non-leguminous crop species. Future research on understanding the molecular mechanisms that underlie strain and host variability is warranted.

scholarly journals Integrated structural and evolutionary analysis reveals common mechanisms underlying adaptive evolution in mammals

2020 ◽  
Vol 117 (11) ◽  
pp. 5977-5986 ◽  
Author(s):  
Greg Slodkowicz ◽  
Nick Goldman
Keyword(s):  
Positive Selection ◽  
Adaptive Evolution ◽  
Evolutionary Biology ◽  
Molecular Mechanisms ◽  
Structural Information ◽  
Protein Structures ◽  
Unexpected Finding ◽  
Evolutionary Analysis ◽  
Genomic Scale ◽  
Evolution Of Mammals

Understanding the molecular basis of adaptation to the environment is a central question in evolutionary biology, yet linking detected signatures of positive selection to molecular mechanisms remains challenging. Here we demonstrate that combining sequence-based phylogenetic methods with structural information assists in making such mechanistic interpretations on a genomic scale. Our integrative analysis shows that positively selected sites tend to colocalize on protein structures and that positively selected clusters are found in functionally important regions of proteins, indicating that positive selection can contravene the well-known principle of evolutionary conservation of functionally important regions. This unexpected finding, along with our discovery that positive selection acts on structural clusters, opens previously unexplored strategies for the development of better models of protein evolution. Remarkably, proteins where we detect the strongest evidence of clustering belong to just two functional groups: Components of immune response and metabolic enzymes. This gives a coherent picture of pathogens and xenobiotics as important drivers of adaptive evolution of mammals.

scholarly journals Baby fish working out: an epigenetic source of adaptive variation in the cichlid jaw

2017 ◽  
Vol 284 (1860) ◽  
pp. 20171018 ◽  
Author(s):  
Yinan Hu ◽  
R. Craig Albertson
Keyword(s):  
Phenotypic Variation ◽  
Evolutionary Biology ◽  
Mechanical Load ◽  
Skeletal Development ◽  
Experimental Manipulation ◽  
Adaptive Variation ◽  
Skeletal Morphology ◽  
Trophic Morphology ◽  
Evo Devo ◽  
Working Out

Understanding the developmental processes that underlie the production of adaptive variation (i.e. the ‘arrival of the fittest’) is a major goal of evolutionary biology. While most evo-devo studies focus on the genetic underpinnings of adaptive phenotypic variation, factors beyond changes in nucleotide sequence can also play a major role in shaping developmental outcomes. Here, we document a vigorous but enigmatic gaping behaviour during the early development of Lake Malawi cichlid larvae. The onset of the behaviour precedes the formation of bone, and we predicted that it might influence craniofacial shape by affecting the mechanical environment in which bone develops. Consistent with this, we found that both natural variation and experimental manipulation of this behaviour induced differential skeletal development that foreshadows adaptive variation in adult trophic morphology. In fact, the magnitude of difference in skeletal morphology induced by these simple shifts in behaviour was similar to those predicted to be caused by genetic factors. Finally, we demonstrate that this mechanical-load-induced shift in skeletal development is associated with differences in ptch1 expression, a gene previously implicated in mediating between-species differences in skeletal shape. Our results underscore the complexity of development, and the importance of epigenetic ( sensu Waddington) mechanisms in determining adaptive phenotypic variation.

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