Abalones are important farming species with a high economic value. They have already been farmed for more than 50 years. As problems and new requirements rose continuously in culture industry of abalone, studies on ge...Abalones are important farming species with a high economic value. They have already been farmed for more than 50 years. As problems and new requirements rose continuously in culture industry of abalone, studies on genetic and breeding techniques are needed to improve characteristics and to gain new traits. This review concentrates on advances in genetics and breeding techniques in abalone.As for genetic studies, karyological analyses, allozyme, DNA markers and genetic diversity were reviewed. So far, karyological analyses in abalone have been performed in 12 species that can be divided into three groups according to the chromosome number. In some economically important species, loci of allozymes and microsatellites have been isolated and applied to investigate the genetic structure of natural and hatchery populations and to identify the result of chromosome set manipulation, but the related reports are only a few yet. The resultsof investigation with DNA markers and allozymes showed that the genetic structure of natural populations presents two characteristics: excessive homozygosity and subdivision.Advances of various breeding techniques, including introduction, selection, hybridization, polyploidy, gynogenesis and gene manipulation, were reviewed in the other part.Although Haliotis discus discus, introduced from Japan, has become one of the most important culture species in China, the economic, social and environmental effects of introduction have been rarely studied. Selection is one of the most important and basic breeding techniques, but the studies on selection are only a few and preliminary, referring to the relations between genetic characteristics and the traits of growth and resistance, genetic diversity and heritability of quantitative traits, and the effect of selection. Interspecific hybridization was the first breeding program carried out in abalone.Experimental hybridization have been carried out for about 20 crosses. Heterosis, such as faster growth and high survival rate, has been observed in some crosses. Triploids have been successfully induced in many species of abalone with physical or chemical shock, e.g. H. discus hannai, H. rufescens, H.diversicolor diversicolor and H. midae.Field experiments were conducted in some species of triploid abalone. In comparison with triploid, the research on tetraploid is still in quest stage. The progress of induction of gynogenesis in abalone is quite slow. Conditions of sperm inactivation,diploid restoration and nuclear behavior of gynogenetically activated eggs have been researched on in H. discus hannai. Notwithstanding the gene transfer technology in abalone is in the quest stage, the research have already involved preparation of exogenic DNA, means of gene transfer, identification integration and expression of target gene,etc. Three research directions in these topics were proposed: to investigate the germplasm resources of abalone deeply and widely, to make use of traditional breeding methods and modern biotechnique synthetically, and to combine the science research with production practice.展开更多
为了提高对皱纹盘鲍染色体的辨识水平,实验利用Ba(OH)2处理显示了皱纹盘鲍染色体的C带,并用荧光原位杂交分析(fluorescence in situ hybridization,FISH)研究了核糖体大亚基rDNA在皱纹盘鲍中期染色体上的数目与位置。核型结果显示,皱纹...为了提高对皱纹盘鲍染色体的辨识水平,实验利用Ba(OH)2处理显示了皱纹盘鲍染色体的C带,并用荧光原位杂交分析(fluorescence in situ hybridization,FISH)研究了核糖体大亚基rDNA在皱纹盘鲍中期染色体上的数目与位置。核型结果显示,皱纹盘鲍染色体组包含7对中部着丝粒染色体和8对亚中部着丝粒染色体,另有3对染色体介于中部着丝粒染色体与亚中着丝粒染色体之间(m/sm)。C显带结果显示,8对染色体有稳定的着丝粒C带,5～7对染色体上有中期相间多态的端部C带,3对染色体上有同源染色体异态的臂间C带。FISH分析显示,皱纹盘鲍中期染色体上分布着4个大亚基rDNA位点,分别位于2号短臂(2S)、7号短臂(7S)、12号短臂(12S)和18号长臂(18L)的端部。研究结果为皱纹盘鲍染色体辨识提供了新的特征与标记,为进一步研究皱纹盘鲍种群的染色体多态和鲍属染色体进化提供了基础资料。展开更多
文摘Abalones are important farming species with a high economic value. They have already been farmed for more than 50 years. As problems and new requirements rose continuously in culture industry of abalone, studies on genetic and breeding techniques are needed to improve characteristics and to gain new traits. This review concentrates on advances in genetics and breeding techniques in abalone.As for genetic studies, karyological analyses, allozyme, DNA markers and genetic diversity were reviewed. So far, karyological analyses in abalone have been performed in 12 species that can be divided into three groups according to the chromosome number. In some economically important species, loci of allozymes and microsatellites have been isolated and applied to investigate the genetic structure of natural and hatchery populations and to identify the result of chromosome set manipulation, but the related reports are only a few yet. The resultsof investigation with DNA markers and allozymes showed that the genetic structure of natural populations presents two characteristics: excessive homozygosity and subdivision.Advances of various breeding techniques, including introduction, selection, hybridization, polyploidy, gynogenesis and gene manipulation, were reviewed in the other part.Although Haliotis discus discus, introduced from Japan, has become one of the most important culture species in China, the economic, social and environmental effects of introduction have been rarely studied. Selection is one of the most important and basic breeding techniques, but the studies on selection are only a few and preliminary, referring to the relations between genetic characteristics and the traits of growth and resistance, genetic diversity and heritability of quantitative traits, and the effect of selection. Interspecific hybridization was the first breeding program carried out in abalone.Experimental hybridization have been carried out for about 20 crosses. Heterosis, such as faster growth and high survival rate, has been observed in some crosses. Triploids have been successfully induced in many species of abalone with physical or chemical shock, e.g. H. discus hannai, H. rufescens, H.diversicolor diversicolor and H. midae.Field experiments were conducted in some species of triploid abalone. In comparison with triploid, the research on tetraploid is still in quest stage. The progress of induction of gynogenesis in abalone is quite slow. Conditions of sperm inactivation,diploid restoration and nuclear behavior of gynogenetically activated eggs have been researched on in H. discus hannai. Notwithstanding the gene transfer technology in abalone is in the quest stage, the research have already involved preparation of exogenic DNA, means of gene transfer, identification integration and expression of target gene,etc. Three research directions in these topics were proposed: to investigate the germplasm resources of abalone deeply and widely, to make use of traditional breeding methods and modern biotechnique synthetically, and to combine the science research with production practice.
文摘为了提高对皱纹盘鲍染色体的辨识水平,实验利用Ba(OH)2处理显示了皱纹盘鲍染色体的C带,并用荧光原位杂交分析(fluorescence in situ hybridization,FISH)研究了核糖体大亚基rDNA在皱纹盘鲍中期染色体上的数目与位置。核型结果显示,皱纹盘鲍染色体组包含7对中部着丝粒染色体和8对亚中部着丝粒染色体,另有3对染色体介于中部着丝粒染色体与亚中着丝粒染色体之间(m/sm)。C显带结果显示,8对染色体有稳定的着丝粒C带,5～7对染色体上有中期相间多态的端部C带,3对染色体上有同源染色体异态的臂间C带。FISH分析显示,皱纹盘鲍中期染色体上分布着4个大亚基rDNA位点,分别位于2号短臂(2S)、7号短臂(7S)、12号短臂(12S)和18号长臂(18L)的端部。研究结果为皱纹盘鲍染色体辨识提供了新的特征与标记,为进一步研究皱纹盘鲍种群的染色体多态和鲍属染色体进化提供了基础资料。
