Trans-species evolution of Mhc-DRB haplotype polymorphism in primates: Organization of DRB genes in the chimpanzee

1992 ◽  
Vol 36 (1) ◽  
pp. 39-48 ◽  
Author(s):  
Uwe Br�ndle ◽  
Hideki Ono ◽  
Vladimir Vincek ◽  
Dagmar Klein ◽  
Mladen Golubic ◽  
...  
Keyword(s):  
Species Evolution

Coexistence of fluorescent Escherichia coli strains in millifluidic droplets reactors

Lab on a Chip ◽  
2021 ◽  
Author(s):  
Xinne Zhao ◽  
Rico Illing ◽  
Philip Ruelens ◽  
Michael Bachmann ◽  
Gianaurelio Cuniberti ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Clinical Importance ◽  
Competition And Cooperation ◽  
Species Evolution

Understanding competition and cooperation within microbiota is of high fundamental and clinical importance, helping to comprehend species’ evolution and biodiversity. We co-encapsulated and cultured two isogenic Escherichia coli strains expressing...

Brain size evolution in small mammals: test of the expensive tissue hypothesis

Mammalia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ying Jiang ◽  
Jia Yu Wang ◽  
Xiao Fu Huang ◽  
Chun Lan Mai ◽  
Wen Bo Liao
Keyword(s):  
Small Mammals ◽  
Brain Size ◽  
Reproductive Investment ◽  
Generalized Least Squares ◽  
Offspring Number ◽  
Size Evolution ◽  
Large Brain ◽  
Species Evolution ◽  
The Cost ◽  
Expensive Tissue Hypothesis

Abstract Brain size exhibits significant changes within and between species. Evolution of large brains can be explained by the need to improve cognitive ability for processing more information in changing environments. However, brains are among the most energetically expensive organs. Enlarged brains can impose energetic demands that limit brain size evolution. The expensive tissue hypothesis (ETH) states that a decrease in the size of another expensive tissue, such as the gut, should compensate for the cost of a large brain. We studied the interplay between energetic limitations and brain size evolution in small mammals using phylogenetically generalized least squares (PGLS) regression analysis. Brain mass was not correlated with the length of the digestive tract in 37 species of small mammals after correcting for phylogenetic relationships and body size effects. We further found that the evolution of a large brain was not accompanied by a decrease in male reproductive investments into testes mass and in female reproductive investment into offspring number. The evolution of brain size in small mammals is inconsistent with the prediction of the ETH.

scholarly journals Detecting environment-dependent diversification from phylogenies: a simulation study and some empirical illustrations

2017 ◽  
Author(s):  
Eric Lewitus ◽  
Hélène Morlon
Keyword(s):  
Environmental Variables ◽  
Relative Importance ◽  
Species Trees ◽  
Major Goal ◽  
Explanatory Variables ◽  
Extinction Rates ◽  
Dependency Tree ◽  
Species Evolution ◽  
Abiotic Variables

AbstractUnderstanding the relative influence of various abiotic and biotic variables on diversification dynamics is a major goal of macroevolutionary studies. Recently, phylogenetic approaches have been developed that make it possible to estimate the role of various environmental variables on diversification using time-calibrated species trees, paleoenvironmental data, and maximum-likelihood techniques. These approaches have been effectively employed to estimate how speciation and extinction rates vary with key abiotic variables, such as temperature and sea level, and we can anticipate that they will be increasingly used in the future. Here we compile a series of biotic and abiotic paleodatasets that can be used as explanatory variables in these models and use simulations to assess the statistical properties of the approach when applied to these paleodatasets. We demonstrate that environment-dependent models perform well in recovering environment-dependent speciation and extinction parameters, as well as in correctly identifying the simulated environmental model when speciation isenvironment-dependent. We explore how the strength of the environment-dependency, tree size, missing taxa, and characteristics of the paleoenvironmental curves influence the performance of the models. Finally, using these models, we infer environment-dependent diversification in three empirical phylogenies: temperature-dependence in Cetacea,δ13C-dependence in Ruminantia, andCO2-dependence in Portulacaceae. We illustrate how to evaluate the relative importance of abiotic and biotic variables in these three clades and interpret these results in light of macroevolutionary hypotheses for mammals and plants. Given the important role paleoenvironments are presumed to have played in species evolution, our statistical assessment of how environment-dependent models behave is crucial for their utility in macroevolutionary analysis.

scholarly journals Comparative Transcriptomics Provides Insight into Floral Color Polymorphism in a Pleione limprichtii Orchid Population

2019 ◽  
Vol 21 (1) ◽  
pp. 247 ◽  
Author(s):  
Yiyi Zhang ◽  
Tinghong Zhou ◽  
Zhongwu Dai ◽  
Xiaoyu Dai ◽  
Wei Li ◽  
...  
Keyword(s):  
Distribution Pattern ◽  
Expression Patterns ◽  
Color Polymorphism ◽  
Color Variation ◽  
Similar Species ◽  
Color Formation ◽  
Floral Color ◽  
Species Evolution ◽  
Different Color ◽  
Insight Into

Floral color polymorphism can provide great insight into species evolution from a genetic and ecological standpoint. Color variations between species are often mediated by pollinators and are fixed characteristics, indicating their relevance to adaptive evolution, especially between plants within a single population or between similar species. The orchid genus Pleione has a wide variety of flower colors, from violet, rose-purple, pink, to white, but their color formation and its evolutionary mechanism are unclear. Here, we selected the P. limprichtii population in Huanglong, Sichuan Province, China, which displayed three color variations: Rose-purple, pink, and white, providing ideal material for exploring color variations with regard to species evolution. We investigated the distribution pattern of the different color morphs. The ratio of rose-purple:pink:white-flowered individuals was close to 6:3:1. We inferred that the distribution pattern may serve as a reproductive strategy to maintain the population size. Metabolome analysis was used to reveal that cyanindin derivatives and delphidin are the main color pigments involved. RNA sequencing was used to characterize anthocyanin biosynthetic pathway-related genes and reveal different color formation pathways and transcription factors in order to identify differentially-expressed genes and explore their relationship with color formation. In addition, qRT-PCR was used to validate the expression patterns of some of the genes. The results show that PlFLS serves as a crucial gene that contributes to white color formation and that PlANS and PlUFGT are related to the accumulation of anthocyanin which is responsible for color intensity, especially in pigmented flowers. Phylogenetic and co-expression analyses also identified a R2R3-MYB gene PlMYB10, which is predicted to combine with PlbHLH20 or PlbHLH26 along with PlWD40-1 to form an MBW protein complex (MYB, bHLH, and WDR) that regulates PlFLS expression and may serve as a repressor of anthocyanin accumulation-controlled color variations. Our results not only explain the molecular mechanism of color variation in P. limprichtii, but also contribute to the exploration of a flower color evolutionary model in Pleione, as well as other flowering plants.

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