scholarly journals The contribution of neutral evolution and adaptive processes in driving phenotypic divergence in a model mammalian species, the Andean fox Lycalopex culpaeus

2018 ◽  
Vol 45 (5) ◽  
pp. 1114-1125 ◽  
Author(s):  
Pablo A. Martinez ◽  
Monica V. Pia ◽  
Ilham A. Bahechar ◽  
Wagner F. Molina ◽  
Claudio J. Bidau ◽  
...  
Keyword(s):  
Mammalian Species ◽  
Neutral Evolution ◽  
Phenotypic Divergence ◽  
Adaptive Processes ◽  
Andean Fox

scholarly journals Adaptation to local ultraviolet radiation conditions among neighbouring Daphnia populations

2010 ◽  
Vol 278 (1710) ◽  
pp. 1306-1313 ◽  
Author(s):  
Brooks E. Miner ◽  
Benjamin Kerr
Keyword(s):  
Ultraviolet Radiation ◽  
Environmental Variables ◽  
Population Genetic ◽  
Phenotypic Diversity ◽  
Experimental Population ◽  
Phenotypic Divergence ◽  
Trade Offs ◽  
Adaptive Processes ◽  
Subdivided Populations ◽  
Radiation Conditions

Understanding the historical processes that generated current patterns of phenotypic diversity in nature is particularly challenging in subdivided populations. Populations often exhibit heritable genetic differences that correlate with environmental variables, but the non-independence among neighbouring populations complicates statistical inference of adaptation. To understand the relative influence of adaptive and non-adaptive processes in generating phenotypes requires joint evaluation of genetic and phenotypic divergence in an integrated and statistically appropriate analysis. We investigated phenotypic divergence, population-genetic structure and potential fitness trade-offs in populations of Daphnia melanica inhabiting neighbouring subalpine ponds of widely differing transparency to ultraviolet radiation (UVR). Using a combination of experimental, population-genetic and statistical techniques, we separated the effects of shared population ancestry and environmental variables in predicting phenotypic divergence among populations. We found that native water transparency significantly predicted divergence in phenotypes among populations even after accounting for significant population structure. This result demonstrates that environmental factors such as UVR can at least partially account for phenotypic divergence. However, a lack of evidence for a hypothesized trade-off between UVR tolerance and growth rates in the absence of UVR prevents us from ruling out the possibility that non-adaptive processes are partially responsible for phenotypic differentiation in this system.

scholarly journals Constructive Neutral Evolution 20 Years Later

2021 ◽  
Vol 89 (3) ◽  
pp. 172-182 ◽  
Author(s):  
Sergio A. Muñoz-Gómez ◽  
Gaurav Bilolikar ◽  
Jeremy G. Wideman ◽  
Kerry Geiler-Samerotte
Keyword(s):  
Molecular Evolution ◽  
Neutral Evolution ◽  
Explanatory Framework ◽  
Evolution Of Complexity ◽  
Adaptive Processes ◽  
Constructive Neutral Evolution ◽  
Complex Features ◽  
Extensive List

AbstractEvolution has led to a great diversity that ranges from elegant simplicity to ornate complexity. Many complex features are often assumed to be more functional or adaptive than their simpler alternatives. However, in 1999, Arlin Stolzfus published a paper in the Journal of Molecular Evolution that outlined a framework in which complexity can arise through a series of non-adaptive steps. He called this framework Constructive Neutral Evolution (CNE). Despite its two-decade-old roots, many evolutionary biologists still appear to be unaware of this explanatory framework for the origins of complexity. In this perspective piece, we explain the theory of CNE and how it changes the order of events in narratives that describe the evolution of complexity. We also provide an extensive list of cellular features that may have become more complex through CNE. We end by discussing strategies to determine whether complexity arose through neutral or adaptive processes.

The parent-offspring microbiome and neurobehavioral development

2019 ◽  
Vol 42 ◽  
Author(s):  
Jeffrey R. Alberts ◽  
Christopher Harshaw ◽  
Gregory E. Demas ◽  
Cara L. Wellman ◽  
Ardythe L. Morrow
Keyword(s):  
Mammalian Species ◽  
Social Emotional ◽  
Behavioral Measures ◽  
Neurobehavioral Development ◽  
Emotional Function ◽  
Neurobehavioral Outcomes ◽  
Methodological Approaches ◽  
And Behavior

Abstract We identify the significance and typical requirements of developmental analyses of the microbiome-gut-brain (MGB) in parents, offspring, and parent-offspring relations, which have particular importance for neurobehavioral outcomes in mammalian species, including humans. We call for a focus on behavioral measures of social-emotional function. Methodological approaches to interpreting relations between the microbiota and behavior are discussed.

High-voltage EM description of the types and distribution of sensory endings in the inner conical body of the rat vibrissal follicle-sinus complex

1990 ◽  
Vol 48 (3) ◽  
pp. 410-411
Author(s):  
Tony M. Mosconi ◽  
Min J. Song ◽  
Frank L. Rice
Keyword(s):  
Mammalian Species ◽  
Dorsal Side ◽  
Hair Shaft ◽  
Sensory Innervation ◽  
Conical Body ◽  
Adult Rats ◽  
Perpendicular Plane ◽  
Ultrastructural Studies ◽  
Unmyelinated Axons ◽  
Sensory Endings

Whiskers or vibrissal follicle-sinus complexes (F-SCs) on the snouts of many mammalian species are structures that have complex, dense sensory innervation. The innervation of F-SCs is remarkably similar in all species with the exception of one site - the inner conical body (ICB). The ICB is an elongated cylindrical structure that encircles the hair shaft near the neck of the follicle. This site has received only cursory attention in ultrastructural studies of the F-SCAdult rats were perfused after the method of Renehan and Munger2. F-SCs were quartered longitudinally and embedded separately in Epon-Araldite. Serial 0.25 μm sections were cut in either the longitudinal or perpendicular plane through the ICB and examined with an AEI EM7 1.2 MV HVEM (Albany, NY) at 1000 KV. Sensory endings were reconstructed from serial micrographs through at least 20 μm in the longitudinal plane and through 10 μm in the perpendicular plane.From two to six small superficial vibrissal nerves converge upon the neck of the F-SC and descend into the ICB. The nerves branch into smaller bundles of myelinated and unmyelinated axons along the dorsal side of the hair shaft.

Vascular adaptations to hypoxia: molecular and cellular mechanisms regulating vascular tone

2007 ◽  
Vol 43 ◽  
pp. 105-120 ◽  
Author(s):  
Michael L. Paffett ◽  
Benjimen R. Walker
Keyword(s):  
Vascular Tone ◽  
Cellular Proliferation ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Hypoxia Inducible Factor ◽  
Systemic Circulation ◽  
Cellular Mechanisms ◽  
Hypoxia Inducible Factor 1 ◽  
Pulmonary Vasoconstriction ◽  
Adaptive Mechanisms ◽  
Adaptive Processes

Several molecular and cellular adaptive mechanisms to hypoxia exist within the vasculature. Many of these processes involve oxygen sensing which is transduced into mediators of vasoconstriction in the pulmonary circulation and vasodilation in the systemic circulation. A variety of oxygen-responsive pathways, such as HIF (hypoxia-inducible factor)-1 and HOs (haem oxygenases), contribute to the overall adaptive process during hypoxia and are currently an area of intense research. Generation of ROS (reactive oxygen species) may also differentially regulate vascular tone in these circulations. Potential candidates underlying the divergent responses between the systemic and pulmonary circulations may include Nox (NADPH oxidase)-derived ROS and mitochondrial-derived ROS. In addition to alterations in ROS production governing vascular tone in the hypoxic setting, other vascular adaptations are likely to be involved. HPV (hypoxic pulmonary vasoconstriction) and CH (chronic hypoxia)-induced alterations in cellular proliferation, ionic conductances and changes in the contractile apparatus sensitivity to calcium, all occur as adaptive processes within the vasculature.

Load-Bearing in the Ovine Medial Tibial Condyle: Effect of Meniscectomy

1993 ◽  
Vol 06 (02) ◽  
pp. 100-104 ◽  
Author(s):  
D. M. Pickles ◽  
C. R. Bellenger
Keyword(s):  
Knee Joint ◽  
Contact Area ◽  
Mammalian Species ◽  
Total Removal ◽  
Load Bearing ◽  
Human Knee ◽  
Biochemical Effects ◽  
Pressure Sensitive ◽  
Medial Meniscectomy ◽  
Tibial Condyle

SummaryTotal removal of a knee joint meniscus is followed by osteoarthritis in many mammalian species. Altered load-bearing has been observed in the human knee following meniscectomy but less is known about biochemical effects of meniscectomy in other species. Using pressure sensitive paper in sheep knee (stifle) joints it was found that, for comparable loads, the load-bearing area on the medial tibial condyle was significantly reduced following medial meniscectomy. Also, for loads of between 50 N and 500 N applied to the whole joint, the slope of the regression of contact area against load was much smaller. Following medial meniscectomy, the ability to increase contact area as load increased was markedly reduced.The load bearing area on the medial tibial condyle was reduced following meniscectomy.

Diversity of Primary Structures of the Carboxy-terminal Regions of Mammalian Fibrinogen Aα-Chains

1993 ◽  
Vol 69 (04) ◽  
pp. 351-360 ◽  
Author(s):  
Masahiro Murakawa ◽  
Takashi Okamura ◽  
Takumi Kamura ◽  
Tsunefumi Shibuya ◽  
Mine Harada ◽  
...  
Keyword(s):  
Amino Acid ◽  
Rhesus Monkey ◽  
Syrian Hamster ◽  
Tandem Repeats ◽  
Mammalian Species ◽  
Amino Acid Sequences ◽  
Point Of View ◽  
Cross Linking ◽  
Amino Terminal ◽  
Rgd Sequence

SummaryThe partial amino acid sequences of fibrinogen Aα-chains from five mammalian species have been inferred by means of the polymerase chain reaction (PCR). From the genomic DNA of the rhesus monkey, pig, dog, mouse and Syrian hamster, the DNA fragments coding for α-C domains in the Aα-chains were amplified and sequenced. In all species examined, four cysteine residues were always conserved at the homologous positions. The carboxy- and amino-terminal portions of the α-C domains showed a considerable homology among the species. However, the sizes of the middle portions, which corresponded to the internal repeat structures, showed an apparent variability because of several insertions and/or deletions. In the rhesus monkey, pig, mouse and Syrian hamster, 13 amino acid tandem repeats fundamentally similar to those in humans and the rat were identified. In the dog, however, tandem repeats were found to consist of 18 amino acids, suggesting an independent multiplication of the canine repeats. The sites of the α-chain cross-linking acceptor and α2-plasmin inhibitor cross-linking donor were not always evolutionally conserved. The arginyl-glycyl-aspartic acid (RGD) sequence was not found in the amplified region of either the rhesus monkey or the pig. In the canine α-C domain, two RGD sequences were identified at the homologous positions to both rat and human RGD S. In the Syrian hamster, a single RGD sequence was found at the same position to that of the rat. Triplication of the RGD sequences was seen in the murine fibrinogen α-C domain around the homologous site to the rat RGDS sequence. These findings are of some interest from the point of view of structure-function and evolutionary relationships in the mammalian fibrinogen Aα-chains.

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