Molecular basis and genetic improvement of economically important traits in aquaculture animals

Aquaculture has been believed to be a major Chinese contribution to the world. In recent 20 years, genome and other genetic technologies have promoted significant advances in basic studies on molecular basis and genetic improvement of aquaculture animals, and complete genomes of some main aquaculture animals have been sequenced or announced to be sequenced since the beginning of this century. Here, we review some significant breakthrough progress of aquaculture genetic improvement technologies including genome technologies, somatic cell nuclear transfer and stem cell technologies, outline the molecular basis of several economically important traits including reproduction, sex, growth, disease resistance, cold tolerance and hypoxia tolerance, and present a series of candidate trait-related genes. Finally, some application cases of genetic improvement are introduced in aquaculture animals, especially in China, and several development trends are highlighted in the near future.Aquaculture has been believed to be a major Chinese contribution to the world. In recent 20 years, genome and other genetic technologies have promoted significant advances in basic studies on molecular basis and genetic improvement of aquaculture animals, and complete genomes of some main aquaculture animals have been sequenced or announced to be sequenced since the beginning of this century. Here, we review some significant breakthrough progress of aquaculture genetic improvement technologies including genome technologies, somatic cell nuclear transfer and stem cell technologies, outline the molecular basis of several economically important traits including reproduction, sex, growth, disease resistance, cold tolerance and hypoxia tolerance, and present a series of candidate trait-related genes. Finally, some application cases of genetic improvement are introduced in aquaculture animals, especially in China, and several development trends are highlighted in the near future

Apolipoprotein C1 regulates epiboly during gastrulation in zebrafish

Apolipoprotein C1 (Apoc1) is associated with lipoprotein metabolism, but its physiological role during embryogenesis is largely unknown. We reveal a new function of Apoc1b, a transcript isoform of Apoc1, in epiboly during zebrafish gastrulation. Apoc1b is expressed in yolk syncytial layers and in deep cells of the ventral and lateral region of the embryos. It displays a radial gradient with high levels in the interior layer and low levels in the superficial layer. Knockdown of Apoc1b by injecting antisense morpholino (MO) caused the epiboly arrest in deep cells. Moreover, we show that the radial intercalation and the radial gradient distribution of E-cadherin are disrupted both in Apoc1b knockdown and overexpressed embryos. Therefore, Apoc1b controls epiboly via E-cadherin-mediated radial intercalation in a gradient-dependent manner.Apolipoprotein C1 (Apoc1) is associated with lipoprotein metabolism, but its physiological role during embryogenesis is largely unknown. We reveal a new function of Apoc1b, a transcript isoform of Apoc1, in epiboly during zebrafish gastrulation. Apoc1b is expressed in yolk syncytial layers and in deep cells of the ventral and lateral region of the embryos. It displays a radial gradient with high levels in the interior layer and low levels in the superficial layer. Knockdown of Apoc1b by injecting antisense morpholino (MO) caused the epiboly arrest in deep cells. Moreover, we show that the radial intercalation and the radial gradient distribution of E-cadherin are disrupted both in Apoc1b knockdown and overexpressed embryos. Therefore, Apoc1b controls epiboly via E-cadherin-mediated radial intercalation in a gradient-dependent manner

Identification and characterization of one novel type of Triactinospomyxon with short spore axis

This study identifies and characterizes one novel type of triactinospomyxon in oligochaete specimen of Branchiura sowerbyi Beddard collected from a fish pond used for rearing gibel carp located in Caidian Experimental Station of the Institute of Hydrobiology. It is nominated as Triactinospomyxon caidianensis type. The spore is of characteristic triactinomyxon "anchor" shape and possesses a spore body with sporoplasm containing 32 germ cells, 3 polar capsules, and 3 caudal processes. Compared with other triactinomyxon spores described previously, T. caidianensis type has a short spore axis with 76.5 mu m in length and a very short style with 38.9 mu m in length. Molecular analyses on 18S rDNA sequences indicate that the novel T. caidianensis type is most closely related to Triactinomyxon sp SA-2005, Antonactinomyxon sp KAB-2001, and Synactinomyxon sp KAB-2001 with 80.33% to 81.92% identities. On the basis of spore morphology and genetic data, the T. caidianensis type presented in this paper differs from those already known and described in the literatures.This study identifies and characterizes one novel type of triactinospomyxon in oligochaete specimen of Branchiura sowerbyi Beddard collected from a fish pond used for rearing gibel carp located in Caidian Experimental Station of the Institute of Hydrobiology. It is nominated as Triactinospomyxon caidianensis type. The spore is of characteristic triactinomyxon "anchor" shape and possesses a spore body with sporoplasm containing 32 germ cells, 3 polar capsules, and 3 caudal processes. Compared with other triactinomyxon spores described previously, T. caidianensis type has a short spore axis with 76.5 mu m in length and a very short style with 38.9 mu m in length. Molecular analyses on 18S rDNA sequences indicate that the novel T. caidianensis type is most closely related to Triactinomyxon sp SA-2005, Antonactinomyxon sp KAB-2001, and Synactinomyxon sp KAB-2001 with 80.33% to 81.92% identities. On the basis of spore morphology and genetic data, the T. caidianensis type presented in this paper differs from those already known and described in the literatures

High male incidence and evolutionary implications of triploid form in northeast Asia Carassius auratus complex

Carassius auratus complex is believed to originate from East Eurasia and consist of diploid and triploid forms. Diploid form reproduces sexually, whereas triploid form possesses mixture modes of unisexual gynogenesis and sexual reproduction, which makes it a unique case to study evolutionary issues among vertebrates. In this study, we identified 337 triploid individuals from 386 specimens of Carassius auratus complex sampled from 4 different sites of Xingkai Lake and Suifen River on the northeast Asia transboundary areas of Russia and China, and found that triploids were ubiquitous, whereas diploids existed only in SII site of Suifen River. Triploid males were detected in all surveyed sites, and an unusually high triploid male incidence (23%) was found in the Chinese reach of Suifen River. Then, nuclear and cytoplasmic markers were used to analyze their genetic diversity and phylogenetic relationship. A total of 61 distinct tf alleles and 35 mtDNA CR haplotypes were revealed. Higher genetic diversity and divergence were confirmed in triploids than in diploids, and identical genetic background between triploid males and females was demonstrated. Moreover, evolutionary implications and roles of triploid males were suggested in population proliferation and diversity creation of the triploid form. (C) 2012 Elsevier Inc. All rights reserved.Carassius auratus complex is believed to originate from East Eurasia and consist of diploid and triploid forms. Diploid form reproduces sexually, whereas triploid form possesses mixture modes of unisexual gynogenesis and sexual reproduction, which makes it a unique case to study evolutionary issues among vertebrates. In this study, we identified 337 triploid individuals from 386 specimens of Carassius auratus complex sampled from 4 different sites of Xingkai Lake and Suifen River on the northeast Asia transboundary areas of Russia and China, and found that triploids were ubiquitous, whereas diploids existed only in SII site of Suifen River. Triploid males were detected in all surveyed sites, and an unusually high triploid male incidence (23%) was found in the Chinese reach of Suifen River. Then, nuclear and cytoplasmic markers were used to analyze their genetic diversity and phylogenetic relationship. A total of 61 distinct tf alleles and 35 mtDNA CR haplotypes were revealed. Higher genetic diversity and divergence were confirmed in triploids than in diploids, and identical genetic background between triploid males and females was demonstrated. Moreover, evolutionary implications and roles of triploid males were suggested in population proliferation and diversity creation of the triploid form. (C) 2012 Elsevier Inc. All rights reserved