The Experts below are selected from a list of 189 Experts worldwide ranked by ideXlab platform
Samantha V Beck - One of the best experts on this subject based on the ideXlab platform.
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plio pleistocene phylogeography of the southeast asian blue panchax killifish Aplocheilus panchax
2017Co-Authors: Gary R. Carvalho, Samantha V Beck, Axel Barlow, Lukas Ruber, Heok Hui Tan, Estu Nugroho, Daisy Wowor, Siti Azizah Mohd NorAbstract:The complex climatic and geological history of Southeast Asia has shaped this region’s high biodiversity. In particular, sea level fluctuations associated with repeated glacial cycles during the Pleistocene both facilitated, and limited, connectivity between populations. In this study, we used data from two mitochondrial and three anonymous nuclear markers to determine whether a fresh/brackish water killifish, Aplocheilus panchax, Hamilton, 1822, could be used to further understand how climatic oscillations and associated sea level fluctuations have shaped the distribution of biota within this region, and whether such patterns show evidence of isolation within palaeodrainage basins. Our analyses revealed three major mitochondrial clades within A. panchax. The basal divergence of A. panchax mitochondrial lineages was approximately 3.5 Ma, whilst the subsequent divergence timings of these clades occurred early Pleistocene (~2.6 Ma), proceeding through the Pleistocene. Continuous phylogeographic analysis showed a clear west-east dispersal followed by rapid radiation across Southeast Asia. Individuals from Krabi, just north of the Isthmus of Kra, were more closely related to the Indian lineages, providing further evidence for a freshwater faunal disjunction at the Isthmus of Kra biogeographic barrier. Our results suggest that Sulawesi, across the Wallace Line, was colonised relatively recently (~30 ka). Nuclear DNA is less geographically structured, although Mantel tests indicated that nuclear genetic distances were correlated with geographic proximity. Overall, these results imply that recent gene flow, as opposed to historical isolation, has been the key factor determining patterns of nuclear genetic variation in A. panchax, however, some evidence of historical isolation is retained within the mitochondrial genome. Our study further validates the existence of a major biogeographic boundary at the Kra Isthmus, and also demonstrates the use of widely distributed fresh/brackishwater species in phylogeographic studies, and their ability to disperse across major marine barriers in relatively recent time periods.
Siti Azizah Mohd Nor - One of the best experts on this subject based on the ideXlab platform.
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plio pleistocene phylogeography of the southeast asian blue panchax killifish Aplocheilus panchax
2017Co-Authors: Gary R. Carvalho, Samantha V Beck, Axel Barlow, Lukas Ruber, Heok Hui Tan, Estu Nugroho, Daisy Wowor, Siti Azizah Mohd NorAbstract:The complex climatic and geological history of Southeast Asia has shaped this region’s high biodiversity. In particular, sea level fluctuations associated with repeated glacial cycles during the Pleistocene both facilitated, and limited, connectivity between populations. In this study, we used data from two mitochondrial and three anonymous nuclear markers to determine whether a fresh/brackish water killifish, Aplocheilus panchax, Hamilton, 1822, could be used to further understand how climatic oscillations and associated sea level fluctuations have shaped the distribution of biota within this region, and whether such patterns show evidence of isolation within palaeodrainage basins. Our analyses revealed three major mitochondrial clades within A. panchax. The basal divergence of A. panchax mitochondrial lineages was approximately 3.5 Ma, whilst the subsequent divergence timings of these clades occurred early Pleistocene (~2.6 Ma), proceeding through the Pleistocene. Continuous phylogeographic analysis showed a clear west-east dispersal followed by rapid radiation across Southeast Asia. Individuals from Krabi, just north of the Isthmus of Kra, were more closely related to the Indian lineages, providing further evidence for a freshwater faunal disjunction at the Isthmus of Kra biogeographic barrier. Our results suggest that Sulawesi, across the Wallace Line, was colonised relatively recently (~30 ka). Nuclear DNA is less geographically structured, although Mantel tests indicated that nuclear genetic distances were correlated with geographic proximity. Overall, these results imply that recent gene flow, as opposed to historical isolation, has been the key factor determining patterns of nuclear genetic variation in A. panchax, however, some evidence of historical isolation is retained within the mitochondrial genome. Our study further validates the existence of a major biogeographic boundary at the Kra Isthmus, and also demonstrates the use of widely distributed fresh/brackishwater species in phylogeographic studies, and their ability to disperse across major marine barriers in relatively recent time periods.
Lukas Ruber - One of the best experts on this subject based on the ideXlab platform.
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plio pleistocene phylogeography of the southeast asian blue panchax killifish Aplocheilus panchax
2017Co-Authors: Gary R. Carvalho, Samantha V Beck, Axel Barlow, Lukas Ruber, Heok Hui Tan, Estu Nugroho, Daisy Wowor, Siti Azizah Mohd NorAbstract:The complex climatic and geological history of Southeast Asia has shaped this region’s high biodiversity. In particular, sea level fluctuations associated with repeated glacial cycles during the Pleistocene both facilitated, and limited, connectivity between populations. In this study, we used data from two mitochondrial and three anonymous nuclear markers to determine whether a fresh/brackish water killifish, Aplocheilus panchax, Hamilton, 1822, could be used to further understand how climatic oscillations and associated sea level fluctuations have shaped the distribution of biota within this region, and whether such patterns show evidence of isolation within palaeodrainage basins. Our analyses revealed three major mitochondrial clades within A. panchax. The basal divergence of A. panchax mitochondrial lineages was approximately 3.5 Ma, whilst the subsequent divergence timings of these clades occurred early Pleistocene (~2.6 Ma), proceeding through the Pleistocene. Continuous phylogeographic analysis showed a clear west-east dispersal followed by rapid radiation across Southeast Asia. Individuals from Krabi, just north of the Isthmus of Kra, were more closely related to the Indian lineages, providing further evidence for a freshwater faunal disjunction at the Isthmus of Kra biogeographic barrier. Our results suggest that Sulawesi, across the Wallace Line, was colonised relatively recently (~30 ka). Nuclear DNA is less geographically structured, although Mantel tests indicated that nuclear genetic distances were correlated with geographic proximity. Overall, these results imply that recent gene flow, as opposed to historical isolation, has been the key factor determining patterns of nuclear genetic variation in A. panchax, however, some evidence of historical isolation is retained within the mitochondrial genome. Our study further validates the existence of a major biogeographic boundary at the Kra Isthmus, and also demonstrates the use of widely distributed fresh/brackishwater species in phylogeographic studies, and their ability to disperse across major marine barriers in relatively recent time periods.
Gary R. Carvalho - One of the best experts on this subject based on the ideXlab platform.
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plio pleistocene phylogeography of the southeast asian blue panchax killifish Aplocheilus panchax
2017Co-Authors: Gary R. Carvalho, Samantha V Beck, Axel Barlow, Lukas Ruber, Heok Hui Tan, Estu Nugroho, Daisy Wowor, Siti Azizah Mohd NorAbstract:The complex climatic and geological history of Southeast Asia has shaped this region’s high biodiversity. In particular, sea level fluctuations associated with repeated glacial cycles during the Pleistocene both facilitated, and limited, connectivity between populations. In this study, we used data from two mitochondrial and three anonymous nuclear markers to determine whether a fresh/brackish water killifish, Aplocheilus panchax, Hamilton, 1822, could be used to further understand how climatic oscillations and associated sea level fluctuations have shaped the distribution of biota within this region, and whether such patterns show evidence of isolation within palaeodrainage basins. Our analyses revealed three major mitochondrial clades within A. panchax. The basal divergence of A. panchax mitochondrial lineages was approximately 3.5 Ma, whilst the subsequent divergence timings of these clades occurred early Pleistocene (~2.6 Ma), proceeding through the Pleistocene. Continuous phylogeographic analysis showed a clear west-east dispersal followed by rapid radiation across Southeast Asia. Individuals from Krabi, just north of the Isthmus of Kra, were more closely related to the Indian lineages, providing further evidence for a freshwater faunal disjunction at the Isthmus of Kra biogeographic barrier. Our results suggest that Sulawesi, across the Wallace Line, was colonised relatively recently (~30 ka). Nuclear DNA is less geographically structured, although Mantel tests indicated that nuclear genetic distances were correlated with geographic proximity. Overall, these results imply that recent gene flow, as opposed to historical isolation, has been the key factor determining patterns of nuclear genetic variation in A. panchax, however, some evidence of historical isolation is retained within the mitochondrial genome. Our study further validates the existence of a major biogeographic boundary at the Kra Isthmus, and also demonstrates the use of widely distributed fresh/brackishwater species in phylogeographic studies, and their ability to disperse across major marine barriers in relatively recent time periods.
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Anonymous nuclear markers for the Blue Panchax killifish (Aplocheilus panchax)
2011Co-Authors: Mark Bruyn, Wendy Grail, Gary R. CarvalhoAbstract:We report the development of twelve single-copy anonymous nuclear polymorphic loci (SCNPs) developed from the ‘Blue Panchax’ killifish, Aplocheilus panchax . Ninety-six clones from a genomic library were examined, and 59 potential loci were tested across individuals from several geographically disparate populations of A. panchax , sampled from across the breadth of this species’ range (India–Sulawesi). All 12 loci reported here amplified successfully in the six populations examined, and showed variation. An average of 18.4 SNPs per kilobase were identified (total of 11,007 bp sequenced per individual). These markers should provide a useful resource for phylogeographic and population genetic studies of Aplocheilus panchax , and may prove useful for studies on other Aplocheilids.
Horst Bleckmann - One of the best experts on this subject based on the ideXlab platform.
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sighted topminnows Aplocheilus lineatus use the lateral line for surface wave discrimination
2002Co-Authors: Joachim Mogdans, Jana Barenbrock, Horst BleckmannAbstract:The topminnow Aplocheilus lineatus detects and localizes the source of water surface waves with its cephalic lateral line system. Previous behavioral experiments with Aplocheilus have been performed with blinded animals. We tested how well sighted Aplocheilus can be trained to discriminate between water surface waves of different frequency and duration and whether the animals used information from the lateral line for discrimination. Our data show that sighted topminnows can be trained to respond to and discriminate between single-frequency water surface waves and that lateral line information is required for the discrimination. Thus, blinding the animals by surgically removing the eyes in many cases is probably not a necessary prerequisite for testing the sensory capabilities of the lateral line in surface-feeding Aplocheilus.
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electrophysiology of the cephalic lateral line of the surface feeding fish Aplocheilus lineatus
1998Co-Authors: Claudia Mohr, Horst BleckmannAbstract:We investigated the responses of primary afferents innervating the cephalic lateral line of the surface-feeding fish Aplocheilus lineatus to sinusoidal surface wave stimuli. All afferents showed ongoing activity. The degree of spike synchronization with the excitatory phase of a wave cycle and/or the firing rate encoded stimulus amplitude. Modulation of the fiber's discharge rate usually reflected the waves' frequency and thus may be used by the fish to determine stimulus frequency. Different primary afferents may show differences in vibration threshold, frequency sensitivity, phase coupling and dynamic amplitude range. Fibers innervating different head neuromasts were, however, not consistently different in their average response properties. Therefore, we conclude that the arrangement of the cephalic lateral line of A. lineatus separates the relevant stimulus parameters into distinct channels to only a limited extent, leaving most of the stimulus analysis for central processing, and that surface feeding does not involve obvious specializations of the peripheral lateral line, compared with midwater fish and surface-feeding amphibians.
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water wave discrimination in the surface feeding fish Aplocheilus lineatus
1997Co-Authors: Dagmar Vogel, Horst BleckmannAbstract:The surface-feeding fish Aplocheilus lineatus uses its cephalic lateral line to detect water surface waves caused by prey insects. The ability of Aplocheilus to discriminate between surface waves with aid of the lateral line system was tested by go/no-go conditioning. Our results show that Aplocheilus can distinguish between single-frequency surface wave stimuli with equal velocity or equal acceleration amplitudes which differ only in frequency. Frequency difference limens were about 15%, i.e. fish distinguished a 20-Hz wave stimulus from a 23-Hz stimulus in 100% of the trials. Aplocheilus can also discriminate between pure sine-wave stimuli and sine waves which show abrupt frequency changes. In contrast, fish were unable to distinguish amplitude-modulated wave stimuli (carrier frequency 20, 40 and 60 Hz, modulation frequency 10 and 20 Hz) from pure sine waves of the same frequency, even if amplitude modulation depth was 80%.