RESUMO
Constructing genetic linkage map is an essential tool to acknowledge genome in aquaculture species. This paper has reviewed the current status of genetic linkage map research, including mapping population, mapping method and molecular markers used to construct linkage map. Linkage map has great potential in marker assisted selection (MAS), gene locating and cloning, and comparative genome mapping. Genetic linkage map with high density and wide coverage of genome will allow cloning the genes which contribute to economically important traits. The ultimate aim of the constructing linkage map is the development of fast-growing, disease-resistant strains of the major aquaculture species.
Assuntos
Mapeamento Cromossômico/métodos , Peixes/genética , Ligação Genética , Marcadores Genéticos , Animais , Crassostrea/genética , Penaeidae/genética , Locos de Características Quantitativas , Seleção GenéticaRESUMO
Cold stress adversely affects plant growth and crop production. Some plants express a series of cold-responsive genes during cold acclimation to reduce the damage of cold stress. Among them, transcription factors play important roles in enhancing plant cold tolerance. A bHLH-type gene OsbHLH1 was isolated from rice. The predicted OsbHLH1 protein has a putative nuclear-localization signal and a putative DNA binding-domain bHLH-ZIP. The genomic sequence of the OsbHLH1 gene is unique in rice genome and has four introns. The transcription of the OsbHLH1 gene was specifically induced in roots of rice seedlings by cold but not by NaCl, PEG and ABA treatments. The OsbHLH1 protein was located in the nucleus of plant cells and had the ability to activate the transcription of the reporter gene in yeast. In addition, OsbHLH1 had the ability to dimerize. These results indicate that the OsbHLH1 may function as a transcription factor in a cold signal-transduction pathway.
Assuntos
Adaptação Fisiológica/fisiologia , Temperatura Baixa , Oryza/fisiologia , Proteínas de Plantas/fisiologia , Sequência de Aminoácidos , Sequência de Bases , Northern Blotting , Southern Blotting , DNA Complementar , Dimerização , Dados de Sequência Molecular , Proteínas de Plantas/química , Proteínas de Plantas/genética , Homologia de Sequência de AminoácidosRESUMO
Gene targeting is a rising technology in molecular biology,which is defined as the introduction of exogeneous DNA to specific site in genome by homologous recombination,and consequently change the hereditary character of the cell. This technology provides a new and powerful means for research in developmental biology,molecular genetics,immunology and medicine. Progresses have been made in exploring gene structure and function,gene expression and regulation,transgene and gene therapy with the application of gene targeting. But there are some problems in gene targeting,especially for the low efficiency. This article just provided a review of the principle and program of gene targeting,and discussed the possible approaches to increase the efficiency of gene targeting.
