scholarly journals Allozyme diversity of european freshwater crayfish of the geniusAustropotamobius

1997 ◽  
pp. 663-676 ◽  
Author(s):  
F. SANTUCCI ◽  
M. IACONELLI ◽  
P. ANDREANI ◽  
R. CIANCHI ◽  
G. NASCETTI ◽  
...  
Keyword(s):  
Freshwater Crayfish ◽  
Allozyme Diversity

Substantial allozyme diversity in the freshwater crayfish Parastacoides tasmanicus supports extensive cryptic speciation

2001 ◽  
Vol 15 (5) ◽  
pp. 667 ◽  
Author(s):  
B. Hansen ◽  
M. Adams ◽  
T. Krasnicki ◽  
A. M. M. Richardson
Keyword(s):  
Taxonomic Revision ◽  
Allozyme Variation ◽  
Initial Study ◽  
Sympatric Species ◽  
Morphological Data ◽  
Freshwater Crayfish ◽  
Allozyme Diversity ◽  
Absolute Minimum ◽  
Allopatric Species ◽  
Allozyme Loci

Allozyme electrophoretic studies on the freshwater crayfish genus Parastacoides Clark suggest the presence of several cryptic species within this morphologically conservative taxon. Two independent allozyme studies were undertaken to assess the validity of the current taxonomy of this monotypic genus. An initial study examined 42 individuals from 10 sample sets for allozyme variation at 22 putative loci, and a subsequent study surveyed an additional 72 specimens from 20 sample sets at 16 putative loci. Both studies revealed the same general outcomes, namely: (1) several instances of sympatric species diagnosable at multiple allozyme loci; (2) numerous examples of putative allopatric species with significant levels of genetic divergence (25–81% fixed difference, 0.30–1.67 Nei distance) well beyond those found between conspecific populations of any parastacid; (3) broad genetic affinities among putative species are inconsistent with currently recognised morphotypes; and (4) low levels of within-population genetic variability, typical of parastacids. Although it is not possible to determine how many species are represented on the basis of these two preliminary studies, the allozyme data nevertheless indicate that an absolute minimum of 11 species and perhaps as many as 19 species are likely to be present in the genus. They indicate the need for a thorough taxonomic revision of the genus using both molecular and morphological data.

Genetic diversity of the extremely rare Habenaria dentata and the rare Habenaria linearifolia (Orchidaceae) in South Korea: implications for population history and conservation

2018 ◽  
Vol 151 (1) ◽  
pp. 48-60
Author(s):  
Mi Yoon Chung ◽  
Hoa Thi Quynh Le ◽  
Sungwon Son ◽  
Huai Zhen Tian ◽  
Myong Gi Chung
Keyword(s):  
Genetic Diversity ◽  
Southern China ◽  
Geographic Location ◽  
Population History ◽  
Population Variation ◽  
Conservation Strategies ◽  
Ancestral Population ◽  
Allozyme Diversity ◽  
Glacial Origin

Background and aims – Since historical events often leave an indelible mark on levels of genetic diversity of plant populations, one may indirectly infer their evolutionary history with the help of current patterns of genetic diversity. The terrestrial orchid Habenaria dentata, an element of warm-temperate/subtropical vegetation, reaches its northernmost limits in the Korean Peninsula, and thus it is extremely rare there. As H. dentata was absent from the Peninsula during the Last Glacial Maximum (LGM), it is likely to be of post-glacial origin having arrived from either a single refugium or multiple refugia. However, its rare, temperate/boreal congener H. linearifolia might have persisted in situ in either macrorefugia or microrefugia on the Peninsula during the LGM.Methods – To test which hypothesis is most appropriate for each species, we investigated levels of allozyme-based (17 loci) genetic diversity and population genetic structure in the two only known populations of H. dentata and in 12 populations of H. linearifolia.Key results – No allozyme diversity was found in H. dentata (He = 0.000), whereas H. linearifolia exhibited low within-population variation (He = 0.060) and high among-population differentiation (FST = 0.237). We found little association between populations in relation to their geographic location; several populations presented individuals belonging to different clusters.Conclusions – Our results suggest that H. dentata likely originated from a single ancestral population (perhaps from southern Japan or southern China) through post-glacial dispersal, whereas H. linearifolia probably survived the LGM in situ in microrefugia situated at low to mid-elevated regions. We further suggest that separate conservation strategies for each species should be employed, given that the two taxa have different ecological and demographic traits and harbour different levels of genetic diversity.

Phylogeny of the Australian freshwater crayfish Cherax destructor-complex (Decapoda : Parastacidae) inferred from four mitochondrial gene regions

2005 ◽  
Vol 19 (3) ◽  
pp. 209 ◽  
Author(s):  
Thuy T. T. Nguyen ◽  
Christopher M. Austin
Keyword(s):  
16S Rrna ◽  
Cytochrome Oxidase ◽  
Mitochondrial Gene ◽  
Large Subunit ◽  
Strong Support ◽  
Interspecific Variation ◽  
Rrna Gene ◽  
Freshwater Crayfish ◽  
Cherax Destructor ◽  
Australian Freshwater

The phylogenetic relationships among 32 individuals of Australian freshwater crayfish belonging to the Cherax destructor-complex were investigated using a dataset comprising sequences from four mitochondrial gene regions: the large subunit rRNA (16S rRNA), cytochrome oxidase I (COI), adenosine triphosphatase 6 (ATPase 6), and cytochrome oxidase III (COIII). A total of 1602 bp was obtained, and a combined analysis of the data produced a tree with strong support (bootstrap values 94–100%) for three divergent lineages, verifying the phylogenetic hypotheses of relationships within the C. destructor species-complex suggested in previous studies. Overall, sequences from the 16S rRNA gene showed the least variation compared to those generated from protein coding genes, which presented considerably greater levels of divergence. The level of divergence within C. destructor was found to be greater than that observed in other species of freshwater crayfish, but interspecific variation among species examined in the present study was similar to that reported previously.

Expression patterns of two carbonic anhydrase genes, Na+/K+-ATPase and V-type H+-ATPase, in the freshwater crayfish, Cherax quadricarinatus, exposed to low pH and high pH

2017 ◽  
Vol 65 (1) ◽  
pp. 50 ◽  
Author(s):  
Muhammad Yousuf Ali ◽  
Ana Pavasovic ◽  
Peter B. Mather ◽  
Peter J. Prentis
Keyword(s):  
Carbonic Anhydrase ◽  
Expression Patterns ◽  
Maximum Level ◽  
Low Ph ◽  
Freshwater Crayfish ◽  
Α Subunit ◽  
Cherax Quadricarinatus ◽  
High Ph ◽  
Internal Ph ◽  
Ph Conditions

Carbonic anhydrase (CA), Na+/K+-ATPase (NKA) and Vacuolar-type H+-ATPase (HAT) play vital roles in osmoregulation and pH balance in decapod crustaceans. As variable pH levels have a significant impact on the physiology of crustaceans, it is crucial to understand the mechanisms by which an animal maintains its internal pH. We examined expression patterns of cytoplasmic (CAc) and membrane-associated form (CAg) of CA, NKA α subunit and HAT subunit a in gills of freshwater crayfish, Cherax quadricarinatus, at three pH levels – 6.2, 7.2 (control) and 8.2 – over 24 h. Expression levels of CAc were significantly increased at low pH and decreased at high pH conditions 24 h after transfer. Expression increased at low pH after 12 h, and reached its maximum level by 24 h. CAg showed a significant increase in expression at 6 h after transfer at low pH. Expression of NKA significantly increased at 6 h after transfer to pH 6.2 and remained elevated for up to 24 h. Expression for HAT and NKA showed similar patterns, where expression significantly increased 6 h after transfer to low pH and remained significantly elevated throughout the experiment. Overall, CAc, CAg, NKA and HAT gene expression is induced at low pH conditions in freshwater crayfish.

Behavioural responses of Australian freshwater crayfish (Cherax cainii and Cherax albidus) to exotic fish odour

2006 ◽  
Vol 54 (6) ◽  
pp. 399 ◽  
Author(s):  
S. G. Height ◽  
G. J. Whisson
Keyword(s):  
Western Australia ◽  
Predatory Fish ◽  
Behavioural Plasticity ◽  
Current Debate ◽  
Freshwater Crayfish ◽  
Indigenous Species ◽  
Exotic Fish ◽  
Behavioural Responses ◽  
Invasive Crayfish ◽  
Australian Freshwater

Exotic finfish and crayfish have been translocated into Western Australia for more than 100 years. Deliberate stocking and subsequent escape from man-made impoundments have resulted in widespread distribution of non-native yabbies (Cherax albidus) and the exotic redfin perch (Perca fluviatilis) in the State’s south-west. Both species are considered invasive and are known to compete with indigenous species for resources. The nature and degree of impact on native marron (Cherax cainii) is unclear and the subject of current debate. Other researchers have hypothesised that invasive species modify their behaviour in the presence of predators in a more rapid and advantageous manner than native species. This greater behavioural plasticity can result in displacement of indigenous species and successful colonisation of invaders. The aim of this study was to investigate behavioural responses of an indigenous crayfish (C. cainii) and an invasive crayfish (C. albidus) to odours from a native predator (Tandanus bostocki) and an exotic predatory fish (P. fluviatilis) present in Western Australia. Crayfish behaviour was observed in individual glass tanks following the addition of odours from native (T. bostocki) or exotic (P. fluviatilis) finfish predators. Marron exhibited minor behavioural modifications when presented with odours from native or exotic finfish. In contrast, the invasive yabby showed greater detection of odours, displaying significant changes in behaviour (P < 0.05). Yabbies also appeared to distinguish between food odour (commercial crayfish feed) and predator odour; however, neither marron nor yabbies displayed behaviour indicating that they could distinguish between a native or exotic fish predator. Results support the hypothesis that invasive crayfish species have a greater capacity for behavioural plasticity than non-invasive crayfish.

scholarly journals Low allozyme heterozygosity in North Pacific and Bering Sea populations of red king crab (Paralithodes camtschaticus): adaptive specialization, population bottleneck, or metapopulation structure?

2011 ◽  
Vol 68 (3) ◽  
pp. 499-506 ◽  
Author(s):  
W. Stewart Grant ◽  
Susan E. Merkouris ◽  
Gordon H. Kruse ◽  
Lisa W. Seeb
Keyword(s):  
Bering Sea ◽  
North Pacific ◽  
Population Bottleneck ◽  
Ice Age ◽  
Red King Crab ◽  
Paralithodes Camtschaticus ◽  
Allozyme Diversity ◽  
King Crab ◽  
Metapopulation Structure ◽  
Adaptive Specialization

AbstractGrant, W. S., Merkouris, S. E., Kruse, G. H., and Seeb, L. W. 2011. Low allozyme heterozygosity in North Pacific and Bering Sea populations of red king crab (Paralithodes camtschaticus): adaptive specialization, population bottleneck, or metapopulation structure? – ICES Journal of Marine Science, 68: . Populations of red king crab in the North Pacific and Bering Sea have declined in response to ocean-climate shifts and to harvesting. An understanding of how populations are geographically structured is important to the management of these depressed resources. Here, the Mendelian variability at 38 enzyme-encoding loci was surveyed in 27 samples (n = 2427) from 18 general locations. Sample heterozygosities were low, averaging HE = 0.015 among samples. Weak genetic structure was detected among three groups of populations, the Bering Sea, central Gulf of Alaska, and Southeast Alaska, but without significant isolation by distance among populations. A sample from Adak Island in the western Aleutians was genetically different from the remaining samples. The lack of differentiation among populations within regions may, in part, be due to post-glacial expansions and a lack of migration-drift equilibrium and to limited statistical power imposed by low levels of polymorphism. Departures from neutrality may reflect the effects of both selective and historical factors. The low allozyme diversity in red king crab may, in part, be attributable to adaptive specialization, background selection, ice-age population bottlenecks, or metapopulation dynamics in a climatically unstable North Pacific.

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