![]() ![]() ![]() The genetic structure of pathogens is expected to parallel that of their hosts, since pathogen dispersal is often assumed to be driven by host dispersal, especially for host-specific and directly transmitted pathogens. There are many studies using host population genetic structure to infer pathogen spread and dynamics in terrestrial systems (e.g., ). Despite the apparent importance of disease in shaping marine ecosystems, there has been surprisingly little research on the population connectivity, genetic structure, and evolutionary dynamics of marine pathogens. In coral reef ecosystems for example, epizootics have led to the die-off of the keystone reef herbivore Diadema antillarum and have impacted corals indirectly. However, our understanding of viral pathogen dispersal in the ocean remains limited despite well-documented epizootics over the past several decades. Disease transmission, epizootics, and pathogen/host distributions have been extensively studied in terrestrial systems. This study advances our understanding of how climate, coastal geography, host life history, and human activity drive patterns of genetic structure and diversity of viruses in marine animals and contributes to the capacity to infer broadscale host population connectivity in marine ecosystems from virus population genetic data.Įpizootics appear to be increasing in many marine ecosystems, significantly impacting marine species and communities and prompting new research into the mechanisms behind how diseases are spread and influenced by host life history strategies. However, some CsRV1 sequences from the US mid-Atlantic shared high genetic similarity with the Gulf of Mexico genotypes, suggesting potential human-mediated movement of CsRV1 between the US mid-Atlantic and Gulf coasts. Phylogenetic analyses of CsRV1 genomes revealed that virus genotypes were divided into four major genogroups consistent with their host geographic origins. To expand our understanding of the genetic diversity of Callinectes sapidus reovirus 1 (CsRV1) across a broad spatial and host life history range of its blue crab host ( Callinectes sapidus), we obtained 22 complete and 96 partial genomic sequences for CsRV1 strains from the US Atlantic coast, Gulf of Mexico, Caribbean Sea, and the Atlantic coast of South America. Oceanic currents, host migration, latitude-based variation in climate, and resulting changes in host life history are all potential drivers of virus connectivity, adaptation, and genetic structure. © 2005 Wiley-Liss, Inc.The movement of viruses in aquatic systems is rarely studied over large geographic scales. Therefore, the cre transgene driven by mouse α-internexin promoter, described here, provides a useful animal model to specifically manipulate genes in the developing nervous system. The motor neurons in the spinal cord did not exhibit any β-galactosidase activity. Furthermore, X-gal-labeled dorsal root ganglionic (DRG) neurons showed positive for α-Internexin in cell bodies but negative in their spinal nerves. Analyses of postnatal day 1 (P1) newborns showed that β-galactosidase activity was detected in the peripheral nervous system (PNS), such as cranial nerves innervating the tongue and the skin as well as spinal nerves to the body trunk. The activity of the Cre recombinase at postnatal day 1 was examined by mating the cre transgenic mice to ROSA26 reporter (R26R) mice with knock-in Cre-mediated recombination. To establish a tissue-specific pattern in the nervous system, we generated a transgenic mouse line expressing Cre DNA recombinase under the control of 1.3 kb α-Internexin promoter. ![]() After introducing DNA constructs into non-neuronal 3T3 fibroblasts and a neuronal Neuro2A cell line by lipofectamine transfection, we observed that the expression of EGFP with 1.3 kb mouse α-internexin promoter was in a neuron-dominant manner. To characterize the function of mouse α-internexin promoter, we designed two different expression constructs driven by 0.7 kb or 1.3 kb of mouse α-internexin 5′-flanking sequences one was the enhanced green fluorescent protein (EGFP) reporter for monitoring specific expression in vitro, and the other was the cre for studying the functional DNA recombinase in transgenic mice. Α-Internexin is a 66 kDa neuronal intermediate filament protein found most abundantly in the neurons of the nervous systems during early development. ![]()
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