scholarly journals Genetic homogeneity and historical expansions of the slipper lobster, Scyllarides brasiliensis, in the south-west Atlantic

2014 ◽  
Vol 65 (1) ◽  
pp. 59 ◽  
Author(s):  
Ghennie T. Rodríguez-Rey ◽  
Antonio M. Solé-Cava ◽  
Cristiano Lazoski

Management strategies for fisheries species require understanding their connectivity and population dynamics. The Brazilian slipper lobster, Scyllarides brasiliensis, is one of the most commercially important slipper lobster species in South America. We investigated, for the first time, the population genetic structure and evolutionary history of this species. Analyses of sequences of the cytochrome oxidase I gene (COI) and the control region (CR) did not reveal any significant genetic structure of S. brasiliensis (N = 202) along 2700 km of the Atlantic coast (COI: ΦST = 0.0004, ΦCT = 0–0.005, P > 0.05; CR: ΦST = 0.004, ΦCT = 0–0.029, P > 0.05). The genetic homogeneity found suggests high levels of gene flow along the area that are possibly related to the high dispersal potential of the planktonic larvae of the species. Furthermore, the data indicate that demographic and geographical expansions of this slipper lobster population have occurred during the late and middle Pleistocene, which could be related to the fluctuating environmental conditions of that period.

2011 ◽  
Vol 102 (3) ◽  
pp. 333-343 ◽  
Author(s):  
K.C. Albernaz ◽  
K.L. Silva-Brandão ◽  
P. Fresia ◽  
F.L. Cônsoli ◽  
C. Omoto

AbstractIntra- and inter-population genetic variability and the demographic history of Heliothis virescens (F.) populations were evaluated by using mtDNA markers (coxI, coxII and nad6) with samples from the major cotton- and soybean-producing regions in Brazil in the growing seasons 2007/08, 2008/09 and 2009/10. AMOVA indicated low and non-significant genetic structure, regardless of geographical scale, growing season or crop, with most of genetic variation occurring within populations. Clustering analyzes also indicated low genetic differentiation. The haplotype network obtained with combined datasets resulted in 35 haplotypes, with 28 exclusive occurrences, four of them sampled only from soybean fields. The minimum spanning network showed star-shaped structures typical of populations that underwent a recent demographic expansion. The recent expansion was supported by other demographic analyzes, such as the Bayesian skyline plot, the unimodal distribution of paired differences among mitochondrial sequences, and negative and significant values of neutrality tests for the Tajima's D and Fu's FS parameters. In addition, high values of haplotype diversity (Ĥ) and low values of nucleotide diversity (π), combined with a high number of low frequency haplotypes and values of θπ<θW, suggested a recent demographic expansion of H. virescens populations in Brazil. This demographic event could be responsible for the low genetic structure currently found; however, haplotypes present uniquely at the same geographic regions and from one specific host plant suggest an initial differentiation among H. virescens populations within Brazil.


2002 ◽  
Vol 53 (5) ◽  
pp. 849 ◽  
Author(s):  
David Gopurenko ◽  
Jane M. Hughes

The population genetic structure of the estuarine crab, Scylla serrata (Forskål, 1775), was examined among shelf-connected locations and across a historical bio-geographic barrier. Over 300 individuals were sampled from multiple locations within coastal regions (western, northern and eastern) of Australia and analysed for mutational differences at a mitochondrial coding gene (COI). Analysis of molecular variance indicated mitochondrial haplotypes to be structured regionally (P < 0.001), which contrasted with evidence of genetic panmixia within regions. Regional genetic structure broadly correlated with hydrological circulation, supporting the contention that release of propagules away from the estuary may allow genetic connectivity among widespread shelf-connected S. serrata populations. That similar patterns of maternal gene flow are absent among trans-oceanic populations may indicate that the spatial scale of effective dispersal for this species is generally limited to areas of coastal shelf. Two distinct clades of haplotypes were geographically separated either side of the Torres Strait, a narrow sea channel connecting the northern and eastern regions of coastal Australia. This pattern of historical genetic separation is concordant with a number of other marine species across northern Australia and may indicate a shared history of vicariance induced by eustasy. Alternatively, we suggest that sundering of S. serrata populations resulting in cladogenesis may have its origins outside of the northern Australian region.


Insects ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 111 ◽  
Author(s):  
Xueting Sun ◽  
Jing Tao ◽  
Alain Roques ◽  
Youqing Luo

Sirex noctilio F. (Hymenoptera: Siricidae: Siricinae), a new invasive species in China, is a significant international forestry pest which, transported via logs and related wood packing materials, has led to environmental damage and substantial economic loss in many countries around the world. It was first detected in China in 2013, and since then infestations have been found in 18 additional sites. Using a 322 bp fragment of the mitochondrial barcode gene COI, we studied the genetic diversity and structure of S. noctilio populations in both native and invaded ranges, with a specific focus in China. Twelve haplotypes were found across the native and invaded distribution of the pest, of which three were dominant; among these there were only one or two mutational steps between each pair of haplotypes. No obvious genetic structure was found other than in Chinese populations. China has a unique and dominant haplotype not found elsewhere, and compared with the rest of the world, the genetic structure of Chinese populations suggested a multiple invasion scenario.


2015 ◽  
Vol 17 (2) ◽  
pp. 371 ◽  
Author(s):  
V. KOUSTENI ◽  
P. KASAPIDIS ◽  
G. KOTOULAS ◽  
P. MEGALOFONOU

Squalus blainville is one of the least studied Mediterranean shark species. Despite being intensively fished in several locations, biological knowledge is limited and no genetic structure information is available. This is the first study to examine the genetic structure of S. blainville in the Mediterranean Sea. Considering the high dispersal potential inferred for other squalid sharks, the hypothesis of panmixia was tested based on a 585 bp fragment of the mitochondrial DNA cytochrome c oxidase subunit I gene from 107 individuals and six nuclear microsatellite loci from 577 individuals. Samples were collected across the Ionian, Aegean and Libyan Seas and off the Balearic Islands. Twenty three additional sequences of Mediterranean and South African origin were retrieved from GenBank and included in the mitochondrial DNA analysis. The overall haplotype diversity was high, in contrast to the low nucleotide diversity. Low and non-significant pairwise ΦST and FST values along with a Bayesian cluster analysis suggested high connectivity with subsequent genetic homogeneity among the populations studied, and thus a high dispersal potential for S. blainville similar to other squalids. The historical demography of the species was also assessed, revealing a pattern of population expansion since the middle Pleistocene. These findings could be considered in species-specific conservation plans, although sampling over a larger spatial scale and more genetic markers are required to fully elucidate the genetic structure and dispersal potential of S. blainville.


2021 ◽  
pp. 251660852098428
Author(s):  
Vikas Bhatia ◽  
Chirag Jain ◽  
Sucharita Ray ◽  
jay Kumar

Objective: To report a case of young male with stroke and bilateral internal carotid artery (ICA) dissection. Background: Cervical Artery Dissection in Stroke Study trial has provided some insight on management of patients with ICA dissection. However, there is a need to modify the management strategies as per specific clinical scenario. Design/Methods: Case report and literature review. Results: A 45-year-old male presented with 1 month old history of acute onset numbness of right half of the body with slurring of speech. Computed tomography angiography showed complete occlusion of left cervical ICA just beyond origin with presence of fusiform dilatation and spiral flap in right extracranial cervical ICA. The patient was started on antiplatelets and taken for endovascular procedure using 2-mesh-based carotid stents. Patient was discharged after 3 days on antiplatelet therapy. At 1-year follow-up, there were no fresh symptoms. Conclusion: This case emphasizes the role of successful endovascular management of carotid dissection in a young male. These clinical situations may not be fully represented in trials, and a case-based approach is required.


2002 ◽  
Vol 81 (2) ◽  
pp. 211-215 ◽  
Author(s):  
R.T. Van Balen ◽  
R.F. Houtgast ◽  
F.M. Van der Wateren ◽  
J. Vandenberghe

AbstractUsing marine planation surfaces, fluvial terraces and a digital terrain model, the amount of eroded rock volume versus time for the Meuse catchment has been computed. A comparison of the amount of eroded volume with the volume of sediment preserved in the Roer Valley Rift System shows that 12% of the eroded volume is trapped in this rift. The neotectonic uplift evolution of the Ardennes is inferred from the incision history of the Meuse River system and compared to the subsidence characteristics of the Roer Valley Rift System. Both areas are characterized by an early Middle Pleistocene uplift event.


PLoS ONE ◽  
2012 ◽  
Vol 7 (5) ◽  
pp. e36608 ◽  
Author(s):  
Jawad Abdelkrim ◽  
Gavin R. Hunt ◽  
Russell D. Gray ◽  
Neil J. Gemmell

2008 ◽  
Vol 59 (3) ◽  
pp. 235 ◽  
Author(s):  
Alicia Slater Schultheis ◽  
Richard Marchant ◽  
Jane Margaret Hughes

In marine and freshwater invertebrate populations, microscale genetic differentiation or ‘genetic patchiness’ is thought to result from variation in the abundance and genetic composition of new recruits at a particular location. In the present study, the role of the adult emergence patterns in genetic patchiness was examined using mtDNA and two microsatellite loci to compare patterns of genetic differentiation in asynchronously (subtropical) and synchronously emerging (temperate) populations of the stone-cased caddisfly Tasimia palpata. A 550 base pair region of the mitochondrial cytochrome c oxidase subunit I gene (COI) was sequenced in at least 14 individuals from each population. Genetic structure was detected only at the reach scale in the subtropical populations and no genetic differentiation was detected in temperate populations. There were more deviations from Hardy–Weinberg equilibrium (HWE) in subtropical populations than in temperate populations where 44% and 12.5%, respectively, of tests for deviations from HWE were significant. Although distinct patterns of genetic structure and deviations from HWE were observed in the subtropical and temperate populations of T. palpata, no conclusive evidence was found to suggest that the differences are caused by differences in emergence patterns. We hypothesise that genetic patchiness must be caused by post-recruitment processes, most likely the preservation of oviposition ‘hotspots’ in subtropical streams.


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