470 million years of conservation of microsatellite loci among fish species

1996 ◽  
Vol 263 (1370) ◽  
pp. 549-557 ◽  

Primers for 18 microsatellite loci originally isolated from whiting (6), stickleback ( Gasterosteus aculeatus, n — 5) and cod ( Gadus morhua, n = 7) were tested across a panel of diverse fish species, representing the three principal superclasses and most principal superorders of fish, to examine conservation of microsatellite regions across distantly related taxa. Three methods were used. First, amplified fragments were analysed by Southern blotting using the relevant microsatellite motif probes. A total of 17 of the tested primer pairs gave a product in the expected size range in at least four of 11 tested species. Second, for two study loci the amplified polymerase chain reaction products were cloned and sequenced in five fish species to reveal a high level of conservation of the flanking and microsatellite sequences. Finally, the 17 loci successfully amplified in non-source species were tested for polymorphism in groups of unrelated individuals from nine species, in several cases revealing extensive polymorphism. Levels of polymorphism were generally high in species from which the loci were derived or among closely related species. The conservation of flanking sequences for particular microsatellite motifs over the span of fish evolution represented in the test species (470 million years) far exceeds that hitherto reported and lends support to the suggestion (derived from studies of whales and marine turtles) that the rate of base substitution in nuclear and mitochondrial sequences is lower in aquatic than terrestrial organisms. A further explanation could be that these sequences, although generally considered neutral, may play an important role in eukaryotic genomes, and may be under strong selective constraints. The study suggests that heterologous primers will be a ready source of polymorphic markers among fish species, but also indicates that caution should be used in cross-species comparisons of variability.

2021 ◽  
Vol 22 (4) ◽  
pp. 1614
Author(s):  
María Esther Rodríguez ◽  
Ismael Cross ◽  
Alberto Arias-Pérez ◽  
Silvia Portela-Bens ◽  
Manuel Alejandro Merlo ◽  
...  

Cytogenomics, the integration of cytogenetic and genomic data, has been used here to reconstruct the evolution of chromosomes 2 and 4 of Solea senegalensis. S. senegalensis is a flat fish with a karyotype comprising 2n = 42 chromosomes: 6 metacentric + 4 submetacentric + 8 subtelocentric + 24 telocentric. The Fluorescence in situ Hybridization with Bacterial Artificial Chromosomes (FISH-BAC) technique was applied to locate BACs in these chromosomes (11 and 10 BACs in chromosomes 2 and 4, respectively) and to generate integrated maps. Synteny analysis, taking eight reference fish species (Cynoglossus semilaevis, Scophthalmus maximus, Sparus aurata, Gasterosteus aculeatus, Xiphophorus maculatus, Oryzias latipes, Danio rerio, and Lepisosteus oculatus) for comparison, showed that the BACs of these two chromosomes of S. senegalensis were mainly distributed in two principal chromosomes in the reference species. Transposable Elements (TE) analysis showed significant differences between the two chromosomes, in terms of number of loci per Mb and coverage, and the class of TE (I or II) present. Analysis of TE divergence in chromosomes 2 and 4 compared to their syntenic regions in four reference fish species (C. semilaevis, S. maximus, O. latipes, and D. rerio) revealed differences in their age of activity compared with those species but less notable differences between the two chromosomes. Differences were also observed in peaks of divergence and coverage of TE families for all reference species even in those close to S. senegalensis, like S. maximus and C. semilaevis. Considered together, chromosomes 2 and 4 have evolved by Robertsonian fusions, pericentric inversions, and other chromosomal rearrangements mediated by TEs.


2010 ◽  
Vol 30 (6) ◽  
pp. 1357-1367 ◽  
Author(s):  
Knut H. Lauritzen ◽  
Olve Moldestad ◽  
Lars Eide ◽  
Harald Carlsen ◽  
Gaute Nesse ◽  
...  

ABSTRACT Mitochondrial dysfunction underlying changes in neurodegenerative diseases is often associated with apoptosis and a progressive loss of neurons, and damage to the mitochondrial genome is proposed to be involved in such pathologies. In the present study we designed a mouse model that allows us to specifically induce mitochondrial DNA toxicity in the forebrain neurons of adult mice. This is achieved by CaMKIIα-regulated inducible expression of a mutated version of the mitochondrial UNG DNA repair enzyme (mutUNG1). This enzyme is capable of removing thymine from the mitochondrial genome. We demonstrate that a continual generation of apyrimidinic sites causes apoptosis and neuronal death. These defects are associated with behavioral alterations characterized by increased locomotor activity, impaired cognitive abilities, and lack of anxietylike responses. In summary, whereas mitochondrial base substitution and deletions previously have been shown to correlate with premature and natural aging, respectively, we show that a high level of apyrimidinic sites lead to mitochondrial DNA cytotoxicity, which causes apoptosis, followed by neurodegeneration.


Author(s):  
C.J. Barrett ◽  
M.L. Johnson ◽  
S.L. Hull

The shanny/common blenny (Lipophrys pholis) and long-spined scorpionfish/bullhead (Taurulus bubalis) are commonly encountered, sympatric species within much of Great Britain's rocky intertidal zones. Despite being prey items of the cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) respectively, and both contributors to the diet of the near-threatened European otter (Lutra lutra), little is known on the population dynamics of the temperate specimens of Great Britain. It is further less known of the degrees of sympatricity between the two fish species and to what extent they are able to coexist. The current study examines spatio-temporal distributions and abundances at various resolutions: monthly population dynamics of both species along England's Yorkshire coast and seasonal population dynamics along the Yorkshire coast and around the Isle of Anglesey, Wales. Studies of their abundances, sizes, degrees of rock pool co-occurrence and diel activities are further examined, which indicate coexistence is maintained when interspecific co-occurrence takes place only between specimens of similar sizes, thus demoting size-related dominance hierarchies.


2021 ◽  
Author(s):  
Marta Eide ◽  
Xiaokang Zhang ◽  
Odd André Karlsen ◽  
Jared V. Goldstone ◽  
John Stegeman ◽  
...  

Abstract How an organism copes with chemicals is largely determined by the genes and proteins that collectively function to defend against, detoxify and eliminate chemical stressors. This integrative network includes receptors and transcription factors, biotransformation enzymes, transporters, antioxidants, and metal- and heat-responsive genes, and is collectively known as the chemical defensome. Although the types of defensome genes are generally conserved in animals, there are important differences in the complement and function of specific genes between species. Teleost fish is the largest group of vertebrate species and can provide valuable insights into the evolution and functional diversity of defensome genes.In this study, we compared the genes comprising the chemical defensome of five fish species that span the teleosteii evolutionary branch often used as model species in toxicological studies and environmental monitoring programs: zebrafish (Danio rerio), Atlantic cod (Gadus morhua), medaka (Oryzias latipes), Atlantic killifish (Fundulus heteroclitus) and three-spined stickleback (Gasterosteus aculeatus). Genome miningrevealed evolved differences in the number and composition of defensome genes that can have implication for how these species sense and respond to environmental pollutants. The results indicate that knowledge regarding the diversity and function of the defensome will be important for toxicological testing and risk assessment studies.


1990 ◽  
Vol 68 (3) ◽  
pp. 482-492 ◽  
Author(s):  
D. A. McLennan ◽  
J. D. McPhail

Cladistic analysis of behavioural interactions during a series of female choice trials revealed three groups of reproductively unsuccessful males in a population of anadromous Gasterosteus aculeatus: inactive losers (losing male did not participate in choice test), active losers (losing male active during choice test), and fighting losers (subgroup of active losers defined by the observation that the female did not immediately follow the first male to approach her). The inactive losers group represents a "no choice" situation. In the remaining two groups, females responded preferentially to the most intensely coloured member of the competing male pair. This preferential response was strongest during the prechoice, captive presentation where the majority of females oriented head-up to, and tracked, the brighter red male. Once released, the female's initial response to the brighter courtship signal was overridden by the behavioural actions of the duller intensity male in 4 out of 12 trials. Although two of these males eventually lost the female to their rival, the remaining two individuals succeeded in spawning. Overall, 10 of 12 females spawned with the brighter red male. Given the brief breeding season and the advantage enjoyed by the most brightly coloured males in mate attraction, a high level of territorial intrusion is one way for an individual to attract a mate if he is surrounded by more intensely coloured neighbours.


2015 ◽  
Vol 78 (3) ◽  
pp. 554-560 ◽  
Author(s):  
CHUKWUJINDU M. A. IWEGBUE ◽  
GODSWILL O. TESI ◽  
LORETTA C. OVERAH ◽  
FRANCISCA I. BASSEY ◽  
FRANK O. NWADUKWE ◽  
...  

The concentrations and profiles of polycyclic aromatic hydrocarbons (PAHs) in 10 popular fish species in the Nigerian market were determined with a view to providing information on the health hazards associated with the consumption of these fish species. The concentrations of PAHs were measured by gas chromatography–mass spectrometry after extraction by ultrasonication with acetone-dichloromethane and clean up. The concentration ranges of the Σ16 PAHs were 20 to 39.6 μg kg−1 for Parachanna obscura (African snake head), 6.8 to 532.3 μg kg−1 for Oreochromis niloticus (tilapia), 7.4 to 91.1 μg kg−1 for Gymnarchus niloticus (Asa), 13.1 to 34.1 μg kg−1 for Sebastes fasciatus (red fish), 11.2 to 80.0 μg kg−1 for Gadus morhua (cod), 23.9 to 34.6 μg kg−1 for Chrysicthys nigrodigitatus (silver cat fish), 63.4 to 131.4 μg kg−1 for Sardinella aurita (sardine), 22 to 52.9 μg kg−1 for Trachurus trachurus (Atlantic horse mackerel), 21.0 to 63.7 μg kg−1 for Scomber scombrus (mackerel), and 27.7 to 44.5 μg kg−1 for Pseudotolithus senegalensis (croaker). Benzo[a]pyrene occurred in 23% of these fish samples at concentrations above the European Union permissible limit of 2.0 μg kg−1. The calculated margins of exposure based on the indicators for occurrence and effects of PAHs were greater than 10,000 indicating no potential risk for the consumers of the species evaluated in this study.


1999 ◽  
Vol 556 ◽  
Author(s):  
A. Honda ◽  
N Taniguchi ◽  
H. Ishikawa ◽  
M. Kawasaki

AbstractThis paper describes a modeling study for general corrosion of copper which is a candidate material for high-level radioactive waste overpacks. The model is a mixed-potential model combined with diffusive transport of reactants and reaction products. The rest potential and corrosion rate of copper in aerated solution were measured while controlling the thickness of a diffusive solution layer on the copper surface using a rotating-disk electrode. Experimental data were used for validation of the model.


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