scholarly journals Taming, Domestication and Exaptation: Trajectories of Transposable Elements in Genomes

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3590
Author(s):  
Pierre Capy
Keyword(s):  
Genetic Variability ◽  
Transposable Elements ◽  
Environmental Constraints ◽  
The Third ◽  
Evolutionary Trajectories ◽  
Pass Through ◽  
Horizontal Transfers ◽  
Population Fitness

During evolution, several types of sequences pass through genomes. Along with mutations and internal genetic tinkering, they are a useful source of genetic variability for adaptation and evolution. Most of these sequences are acquired by horizontal transfers (HT), but some of them may come from the genomes themselves. If they are not lost or eliminated quickly, they can be tamed, domesticated, or even exapted. Each of these processes results from a series of events, depending on the interactions between these sequences and the host genomes, but also on environmental constraints, through their impact on individuals or population fitness. After a brief reminder of the characteristics of each of these states (taming, domestication, exaptation), the evolutionary trajectories of these new or acquired sequences will be presented and discussed, emphasizing that they are not totally independent insofar as the first can constitute a step towards the second, and the second is another step towards the third.

scholarly journals Homology-Free Detection of Transposable Elements Unveils Their Dynamics in Three Ecologically Distinct Rhodnius Species

Genes ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 170 ◽  
Author(s):  
Marcelo R. J. Castro ◽  
Clément Goubert ◽  
Fernando A. Monteiro ◽  
Cristina Vieira ◽  
Claudia M. A. Carareto
Keyword(s):  
New Species ◽  
Genetic Variability ◽  
Transposable Elements ◽  
Species Complex ◽  
De Novo ◽  
Repetitive Sequences ◽  
Sudden Expansion ◽  
Additional Species ◽  
Original Genome ◽  
Evolutionary Trajectories

Transposable elements (TEs) are widely distributed repetitive sequences in the genomes across the tree of life, and represent an important source of genetic variability. Their distribution among genomes is specific to each lineage. A phenomenon associated with this feature is the sudden expansion of one or several TE families, called bursts of transposition. We previously proposed that bursts of the Mariner family (DNA transposons) contributed to the speciation of Rhodnius prolixus Stål, 1859. This hypothesis motivated us to study two additional species of the R. prolixus complex: Rhodnius montenegrensis da Rosa et al., 2012 and Rhodnius marabaensis Souza et al., 2016, together with a new, de novo annotation of the R. prolixus repeatome using unassembled short reads. Our analysis reveals that the total amount of TEs present in Rhodnius genomes (19% to 23.5%) is three to four times higher than that expected based on the original quantifications performed for the original genome description of R. prolixus. We confirm here that the repeatome of the three species is dominated by Class II elements of the superfamily Tc1-Mariner, as well as members of the LINE order (Class I). In addition to R. prolixus, we also identified a recent burst of transposition of the Mariner family in R. montenegrensis and R. marabaensis, suggesting that this phenomenon may not be exclusive to R. prolixus. Rather, we hypothesize that whilst the expansion of Mariner elements may have contributed to the diversification of the R. prolixus-R. robustus species complex, the distinct ecological characteristics of these new species did not drive the general evolutionary trajectories of these TEs.

Experimental Third Ventriculostomy Performed Using Endovascular Surgical Techniques and Their Adaptation to Percutaneous Intradural Neuronavigation: Proof of Concept Cadaver Study

Neurosurgery ◽  
2003 ◽  
Vol 53 (2) ◽  
pp. 387-392 ◽  
Author(s):  
Michael B. Horowitz ◽  
Kamal Ramzipoor ◽  
Ajit Nair ◽  
Susan Miller ◽  
George Rappard ◽  
...  
Keyword(s):  
Third Ventricle ◽  
Surgical Techniques ◽  
Cadaver Study ◽  
Brain Parenchyma ◽  
Third Ventriculostomy ◽  
General Anesthetic ◽  
The Third ◽  
Noncommunicating Hydrocephalus ◽  
Pass Through ◽  
The Brain

Abstract OBJECTIVE Endoscopic third ventriculostomy has developed into a therapeutic alternative to shunting for the management of carefully selected patients with primarily noncommunicating hydrocephalus. This procedure, however, requires a general anesthetic and necessitates violation of the brain parenchyma and manipulation near vital neural structures to access the floor of the third ventricle. Using two cadavers and off-the-shelf angiographic catheters, we sought to determine whether it was possible to navigate a catheter, angioplasty balloon, and stent percutaneously through the subarachnoid space from the thecal sac into the third ventricle so as to perform a third ventriculostomy from below. METHODS Using biplane angiography and off-the-shelf angiographic catheters along with angioplasty balloons and stents, we were able to pass a stent coaxially from the thecal sac to and across the floor of the third ventricle so as to achieve a third ventriculostomy from below. RESULTS Coaxial catheter techniques allowed for the percutaneous insertion of a stent across the floor of the third ventricle. Ventriculostomy was confirmed by injecting contrast medium into the lateral ventricle and seeing it pass through the stent and into the chiasmatic cistern. CONCLUSION We describe the performance of third ventriculostomies in two cadavers by use of the new concept of percutaneous intradural neuronavigation. This procedure may obviate the need for general anesthetic and minimize the potential for brain and vascular injury, especially if ultimately combined with magnetic resonance fluoroscopy.

Winter Navigation through the Strait of Belle Isle

1964 ◽  
Vol 17 (4) ◽  
pp. 364-375
Author(s):  
R. E. G. Simmons
Keyword(s):  
The Third ◽  
The Past ◽  
Shortest Route ◽  
Pack Ice ◽  
Normal Period ◽  
Ice Conditions ◽  
Short Season ◽  
Pass Through ◽  
Alternative Routes ◽  
St Lawrence River

The shortest route from the Great Lakes and St. Lawrence River to Europe passes through the Strait of Belle Isle. The alternative routes pass through the Cabot Strait and are between 100 and 400 miles longer according to the European port of destination. The Strait of Belle Isle is, however, normally closed to navigation from the end of December until the middle of July due to the presence of pack ice and icebergs.Air reconnaissance patrols flown over the Labrador, Belle Isle and East Newfoundland areas seem to indicate that, for the past few years at least, ice conditions have not been so severe as to hamper navigation throughout the normal period of closure. Consolidated ice is only present from the third week of January to mid-February and clears in mid-April to mid-May; only icebergs present a problem in May and June. It is hoped t o show that with proper air reconnaisance at the beginning and end of the ice season, navigation through the Strait could be extended to eight or nine months of the year, or even longer, instead of the present short season of only 5½ months.

scholarly journals Health care logistics: mapping and optimization of patients logistics

2021 ◽  
Vol 12 (8) ◽  
pp. 2161-2179
Author(s):  
Daiane Maria de Genaro Chiroli ◽  
Raíza Conde Coradazi ◽  
Fabio Jose Ceron Branco ◽  
Yslene Rocha Kachba ◽  
Franciely Velozo Aragão ◽  
...  
Keyword(s):  
Linear Programming ◽  
Computational Simulation ◽  
Transportation Of Patients ◽  
Patient Transport ◽  
Specific Approach ◽  
Health Region ◽  
The Third ◽  
City Hall ◽  
Pass Through ◽  
The One

Healthcare logistics play an important role in management, being attributed the activities of acquisition, distribution and movement of materials, professionals and patients. This work aims to develop a study, using the healthcare logistics in the movement of patients in the third health region of Paraná, proposing a linear programming problem that will pass through a computational simulation, considering the existing demands and constraints in the system, aiming to optimize the flow of patients from this region. The present study developed four mathematical models, based on demands and constraints followed by linear programming in order to find the best possible solution for the flow of patients from the third health region of the state of Paraná. The study developed reached its goal of optimization, generating an economy in the transportation of patients. Through the analysis of the results, it is concluded that the model that best suits the presented problem is the one of costs minimization, since the one of vehicles presented higher costs. Possibly the model that minimizes the vehicles would bring better results if the vehicles were not outsourced, but of the Ponta Grossa City Hall (PMPG). Was possible to verify the importance of the theme, especially when referring to the flow of patients in the health services due to the lack of studies with this specific approach. Even with the scarcity of data, it is possible to notice the potential for improvements on this patient transport system.

scholarly journals Intraspecific Molecular Variation of Allium ursinum (Amaryllidaceae) Across the Border of Two Subspecies Distribution Ranges

2015 ◽  
Vol 57 (1) ◽  
pp. 31-43
Author(s):  
Kaja Rola ◽  
Anna Lenart-Boroń ◽  
Piotr Boroń ◽  
Piotr Osyczka
Keyword(s):  
Genetic Variability ◽  
Hybrid Zone ◽  
Mantel Test ◽  
Genetic Group ◽  
Secondary Contact ◽  
Putative Hybrid ◽  
Morphological Pattern ◽  
The Third ◽  
Allium Ursinum ◽  
Distribution Ranges

Abstract The study investigates the genetic differentiation among two subspecies of Allium ursinum L., namely A. ursinum subsp. ursinum and subsp. ucrainicum as well as their putative hybrid that is represented by individuals with intermediate morphology. Inter-Simple Sequence Repeats (ISSR) were applied to determine the status of intermediate morphotypes in terms of their genetic pattern and to assess the level of genetic variability within and between various populations of A. ursinum. The study comprises 144 specimens from nine populations along the east-west transect in Poland, which includes localities of both subspecies and their putative hybrid. Among the examined populations, 48 bands were amplified, of which 45 were found to be polymorphic. The principal coordinate analysis (PCoA), the neighbour-net analysis and Mantel test showed a strong correlation between genetic variability and geographic distance. Analysis of molecular variance (AMOVA) revealed that a greater proportion of total genetic variation resided within populations rather than among them. The Structure Bayesian clustering analysis revealed the presence of three distinct genetic groups within studied populations, where ‘eastern’ genotypes correspond to A. ursinum subsp. ucrainicum, and ‘western’ to subsp. ursinum; whereas the third genetic group has the largest share in the individuals occurring at the border of the distribution ranges of both subspecies. The emergence of the third genetic group is probably an effect of hybridization events occurring within the secondary contact zone. Typical morphologically intermediate populations occur only in a relatively narrow geographical zone, but the hybrid zone revealed by molecular markers is actually much wider than it is suggested by the morphological pattern of individuals. The current distribution pattern of both subspecies of A. ursinum and their hybrid zone is related to the two main directions of postglacial migration of Fagus sylvatica to the area of Poland. The hybrid zone arose as an effect of the secondary contact of two divergent lineages of A. ursinum.

Multiple visits of individual humpback whales (Megaptera novaeangliae) between the Hawaiian and Japanese winter grounds

1999 ◽  
Vol 77 (3) ◽  
pp. 504-508 ◽  
Author(s):  
Dan R Salden ◽  
Louis M Herman ◽  
Manami Yamaguchi ◽  
Fumihiko Sato
Keyword(s):  
Genetic Variability ◽  
North Pacific ◽  
Humpback Whale ◽  
Megaptera Novaeangliae ◽  
Humpback Whales ◽  
Winter Ground ◽  
The Third ◽  
Breeding Populations ◽  
Published Report

We document through photographic identifications three humpback whale (Megaptera novaeangliae) winter ground interchanges between Hawai'i and Japan. Two of these whales, identified as male by their behavioral roles, made multiple interchanges across years; i.e., they were initially seen in Hawai'i, were later observed in Japan, and subsequently, returned to Hawai'i. The third whale was seen in only 2 different years, once in Japan and then in Hawai'i. Prior to this report, there has been only one published report of a Hawai'i-Japan interchange and only eight between Hawai'i and Mexico. None of these involved multiple interchanges. The current findings demonstrate that individual whales may be highly flexible in their annual choice of widely separated winter destinations and suggest that these wanderers may be mainly males. The occurrence of wanderers provides a mechanism for increasing genetic variability in the breeding populations and also suggests a mechanism for noted song similarities across different North Pacific winter grounds.

scholarly journals II. Experimental researches on the strength of pillars of cast iron

1857 ◽  
Vol 8 ◽  
pp. 318-321
Keyword(s):  
Cast Iron ◽  
The Third ◽  
Pass Through ◽  
Experimental Researches

In a previous paper on this subject (Philosophical Transactions, 1840), I had shown,—1st, that a long circular pillar, with its ends flat, was about three times as strong as a pillar of the same length and diameter with its ends rounded in such a manner that the pressure would pass through the axis, the ends being made to turn easily, but not so small as to be crushed by the weight; 2nd, that if a pillar of the same length and diameter as the preceding had one end rounded and one flat, the strength would be twice as great as that of one with both ends rounded; 3rd, if, therefore, three pillars be taken, differing only in the form of their ends, the first having both ends rounded, the second one end rounded and one flat, and the third both ends flat, the strength of these pillars will be as 1—2—3 nearly. The preceding properties having been arrived at experimentally, are here attempted to be demonstrated, at least approximately.

The passage of staphylococci through the bovine teat canal

1968 ◽  
Vol 35 (3) ◽  
pp. 399-406 ◽  
Author(s):  
D. Forbes
Keyword(s):  
Staphylococcus Aureus ◽  
The Other ◽  
Intramammary Infection ◽  
Milk Samples ◽  
The Third ◽  
Colony Forming Unit ◽  
Before And After ◽  
Efficient Machine ◽  
Pass Through ◽  
Teat Canal

SummaryIn order to determine how bacteria pass through the teat canal into the teat sinus, milk samples were taken by syringe, through the teat wall, from 12 quarters of 7 cows, before and after each milking for up to 16 days. Three of the teat canals were naturally infected before the start of the experiment and the remainder were artificially infected with Staphylococcus aureus by the Hadley–Wisconsin swab technique. In 3 of the quarters the inoculum was introduced into the teat sinus through the teat canal by the inoculation technique although the swabs were inserted only 3–5 mm into the canal. The other 9 of the 12 quarters were milked a total of 149 times during the experiment but only once was a colony-forming unit of the bacterium present in a teat canal infection isolated from the milk taken from the teat sinus after milking. One quarter developed an intramammary infection, the bacterium first being detected in the teat sinus prior to the third milking after inoculation of the teat canal. The invasion of the bacteria into the teat sinus therefore occurred between milkings. Staph. aureus persisted in teat canals between 5 and 32 or more milkings after inoculation. The experiment showed that bacteria in the teat canal are seldom refluxed into the residual milk in the teat sinus during correctly conducted milking with an efficient machine.

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