Identification and analysis of evolutionary selection pressures acting at the molecular level in five forkhead subfamilies

Pulmonary surfactant controls the surface tension at the air-liquid interface within the lung. This system had a single evolutionary origin that predates the evolution of the vertebrates and lungs. The lipid composition of surfactant has been subjected to evolutionary selection pressures, particularly temperature, throughout the evolution of the vertebrates.

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At the feet of the master: the search for universalities. Divining the evolutionary selection pressures that resulted in an immune system

Cytogenetic and Genome Research ◽

10.1159/000014957 ◽

1998 ◽

Vol 80 (1-4) ◽

pp. 54-60 ◽

Cited By ~ 8

Author(s):

M. Cohn

Keyword(s):

Immune System ◽

Selection Pressures ◽

Evolutionary Selection

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Preferring and Detecting Face Symmetry: Comparing Children and Adults Judging Human and Monkey Faces

Symmetry ◽

10.3390/sym12122112 ◽

2020 ◽

Vol 12 (12) ◽

pp. 2112

Author(s):

Anthony C. Little ◽

Jack A. F. Griffey

Keyword(s):

Visual System ◽

Age Groups ◽

Perceptual Bias ◽

Partner Choice ◽

Human Face ◽

Partner Preference ◽

Selection Pressures ◽

Evolutionary Selection ◽

Evolutionary Advantage ◽

Human Faces

Background: Visual symmetry is often found attractive. Symmetry may be preferred either due to a bias in the visual system or due to evolutionary selection pressures related to partner preference. Simple perceptual bias views predict that symmetry preferences should be similar across types of stimuli and unlikely to be related to factors such as age. Methods: The current study examined preferences for symmetry across age groups (pre-puberty vs post-puberty) and stimuli type (human face vs monkey face). Pairs of images manipulated for symmetry were presented and participants asked to choose the image they preferred. Participants repeated the task and were asked to detect symmetry. Results: Both age of observer and stimuli type were associated with symmetry preferences. Older observers had higher preferences for symmetry but preferred it most in human vs monkey stimuli. Across both age groups, symmetry preferences and detection abilities were weakly related. Conclusions: The study supports some ideas from an evolutionary advantage view of symmetry preference, whereby symmetry is expected be higher for potential partners (here human faces) and higher post-puberty when partner choice becomes more relevant. Such potentially motivational based preferences challenge perceptual bias explanations as a sole explanation for symmetry preferences but may occur alongside them.

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Genome-Wide Identification of Flowering-Time Genes in Brassica Species and Reveals a Correlation between Selective Pressure and Expression Patterns of Vernalization-Pathway Genes in Brassica napus

International Journal of Molecular Sciences ◽

10.3390/ijms19113632 ◽

2018 ◽

Vol 19 (11) ◽

pp. 3632 ◽

Cited By ~ 3

Author(s):

Haojie Li ◽

Yonghai Fan ◽

Jingyin Yu ◽

Liang Chai ◽

Jingfang Zhang ◽

...

Keyword(s):

Brassica Napus ◽

Flowering Time ◽

Expression Patterns ◽

Brassica Species ◽

Synonymous Substitution ◽

Selection Pressures ◽

Evolutionary Selection ◽

Brassica Crops ◽

Model Plant Arabidopsis Thaliana ◽

Vernalization Pathway

Flowering time is a key agronomic trait, directly influencing crop yield and quality. Many flowering-time genes have been identified and characterized in the model plant Arabidopsis thaliana; however, these genes remain uncharacterized in many agronomically important Brassica crops. In this study, we identified 1064, 510, and 524 putative orthologs of A. thaliana flowering-time genes from Brassica napus, Brassica rapa, and Brassica oleracea, respectively, and found that genes involved in the aging and ambient temperature pathways were fewer than those in other flowering pathways. Flowering-time genes were distributed mostly on chromosome C03 in B. napus and B. oleracea, and on chromosome A09 in B. rapa. Calculation of non-synonymous (Ka)/synonymous substitution (Ks) ratios suggested that flowering-time genes in vernalization pathways experienced higher selection pressure than those in other pathways. Expression analysis showed that most vernalization-pathway genes were expressed in flowering organs. Approximately 40% of these genes were highly expressed in the anther, whereas flowering-time integrator genes were expressed in a highly organ-specific manner. Evolutionary selection pressures were negatively correlated with the breadth and expression levels of vernalization-pathway genes. These findings provide an integrated framework of flowering-time genes in these three Brassica crops and provide a foundation for deciphering the relationship between gene expression patterns and their evolutionary selection pressures in Brassica napus.

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Why Control Activity? Evolutionary Selection Pressures Affecting the Development of Physical Activity Genetic and Biological Regulation

BioMed Research International ◽

10.1155/2013/821678 ◽

2013 ◽

Vol 2013 ◽

pp. 1-10 ◽

Cited By ~ 11

Author(s):

J. Timothy Lightfoot

Keyword(s):

Physical Activity ◽

Future Research ◽

Activity Levels ◽

Control Activity ◽

Hunter Gatherers ◽

Selection Pressures ◽

Biological Regulation ◽

Evolutionary Selection ◽

Energy Expenditures ◽

Genomic Locations

The literature strongly suggests that daily physical activity is genetically and biologically regulated. Potential identities of the responsible mechanisms are unclear, but little has been written concerning the possible evolutionary selection pressures leading to the development of genetic/biological controls of physical activity. Given the weak relationship between exercise endurance and activity levels and the differential genomic locations associated with the regulation of endurance and activity, it is probable that regulation of endurance and activity evolved separately. This hypothesis paper considers energy expenditures and duration of activity in hunter/gatherers, pretechnology farmers, and modern Western societies and considers the potential of each to selectively influence the development of activity regulation. Food availability is also considered given the known linkage of caloric restriction on physical activity as well as early data relating food oversupply to physical inactivity. Elucidating the selection pressures responsible for the genetic/biological control of activity will allow further consideration of these pressures on activity in today’s society, especially the linkages between food and activity. Further, current food abundance is removing the cues for activity that were present for the first 40,000 years of human evolution, and thus future research should investigate the effects of this abundance upon the mechanisms regulating activity.

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The bottleneck may be the solution, not the problem

Behavioral and Brain Sciences ◽

10.1017/s0140525x15000886 ◽

2016 ◽

Vol 39 ◽

Cited By ~ 1

Author(s):

Arnon Lotem ◽

Oren Kolodny ◽

Joseph Y. Halpern ◽

Luca Onnis ◽

Shimon Edelman

Keyword(s):

Working Memory ◽

Language Acquisition ◽

Recent Theory ◽

Cognitive Mechanisms ◽

Selection Pressures ◽

Biological Trait ◽

Memory Bottleneck

AbstractAs a highly consequential biological trait, a memory “bottleneck” cannot escape selection pressures. It must therefore co-evolve with other cognitive mechanisms rather than act as an independent constraint. Recent theory and an implemented model of language acquisition suggest that a limit on working memory may evolve to help learning. Furthermore, it need not hamper the use of language for communication.

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Preparatory Procedures for Electron Microscopic Analysis at the Molecular Level of Resolution

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070230 ◽

1978 ◽

Vol 36 (3) ◽

pp. 516-520

Author(s):

F.J. Sjostrand

Keyword(s):

Electron Microscope ◽

Molecular Level ◽

Microscopic Analysis ◽

Resolving Power ◽

Cellular Structures ◽

Electron Microscopic ◽

Systematic Analysis ◽

Technical Developments ◽

Thin Sectioning ◽

Obvious Reason

In the 1940's and 1950's electron microscopy conferences were attended with everybody interested in learning about the latest technical developments for one very obvious reason. There was the electron microscope with its outstanding performance but nobody could make very much use of it because we were lacking proper techniques to prepare biological specimens. The development of the thin sectioning technique with its perfectioning in 1952 changed the situation and systematic analysis of the structure of cells could now be pursued. Since then electron microscopists have in general become satisfied with the level of resolution at which cellular structures can be analyzed when applying this technique. There has been little interest in trying to push the limit of resolution closer to that determined by the resolving power of the electron microscope.

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RNA polymerase: Preparation and structural analysis of helical polymers

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010011091x ◽

1984 ◽

Vol 42 ◽

pp. 152-153

Author(s):

E. Loren Buhle ◽

Pamela Rew ◽

Ueli Aebi

Keyword(s):

Structural Analysis ◽

Rna Polymerase ◽

Molecular Level ◽

X Ray Diffraction ◽

Helical Polymers ◽

X Ray ◽

E Coli ◽

The Past ◽

Ordered Arrays ◽

Low Ionic Strength

While DNA-dependent RNA polymerase represents one of the key enzymes involved in transcription and ultimately in gene expression in procaryotic and eucaryotic cells, little progress has been made towards elucidation of its 3-D structure at the molecular level over the past few years. This is mainly because to date no 3-D crystals suitable for X-ray diffraction analysis have been obtained with this rather large (MW ~500 kd) multi-subunit (α2ββ'ζ). As an alternative, we have been trying to form ordered arrays of RNA polymerase from E. coli suitable for structural analysis in the electron microscope combined with image processing. Here we report about helical polymers induced from holoenzyme (α2ββ'ζ) at low ionic strength with 5-7 mM MnCl2 (see Fig. 1a). The presence of the ζ-subunit (MW 86 kd) is required to form these polymers, since the core enzyme (α2ββ') does fail to assemble into such structures under these conditions.

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The Current Situation in Chemical Stabilization of Biological Materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100093912 ◽

1972 ◽

Vol 30 ◽

pp. 132-133

Author(s):

John H. Luft

Keyword(s):

Electron Microscopy ◽

Electron Microscope ◽

Osmium Tetroxide ◽

Molecular Level ◽

Cross Linking ◽

Chemical Stabilization ◽

Specimen Preparation ◽

Sufficient Condition ◽

Radio Telescopes

With information processing devices such as radio telescopes, microscopes or hi-fi systems, the quality of the output often is limited by distortion or noise introduced at the input stage of the device. This analogy can be extended usefully to specimen preparation for the electron microscope; fixation, which initiates the processing sequence, is the single most important step and, unfortunately, is the least well understood. Although there is an abundance of fixation mixtures recommended in the light microscopy literature, osmium tetroxide and glutaraldehyde are favored for electron microscopy. These fixatives react vigorously with proteins at the molecular level. There is clear evidence for the cross-linking of proteins both by osmium tetroxide and glutaraldehyde and cross-linking may be a necessary if not sufficient condition to define fixatives as a class.

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