鱼类抗病能力的差异

本文根据国外部分研究结果,阐述了鱼类种间、种群内以及不同种群间抗病力的差异。介绍了关于鱼类抗病力的研究现状和通过遗传改良育种提高鱼类抗病力的途径。     

鱼类杂交育种技术及其在石斑鱼类中的应用

综述了鱼类杂交育种的发展和远缘杂交的应用,以及遗传学在鱼类杂交育种中的应用,并从遗传学角度对石斑鱼类杂交育种的研究现状进行了介绍,简述了通过杂交和选育等遗传育种技术改良种质,获得石斑鱼类优良新品种。将遗传学分析应用于石斑鱼类杂交的研究中,展望了石斑鱼类杂交育种工作的前景。     

养殖鱼类肉质改良与评价的研究进展

目前养殖鱼类的肉质改良主要采用遗传选育、养殖环境及饲料营养调控等技术,而鱼类肉质主要考虑外观特征、肌肉生化组成、感官评分结合质构特性及肌纤维组织学特征等方面。本文对养殖鱼类肉质改良技术及评价方法的研究概况进行了初步的综述,以期为今后养殖鱼类肉质改良技术的创新及评价标准的建立提供一定的参考。     

主要养殖鲑科鱼类遗传育种的研究进展

冷水性鲑科鱼类肉质鲜美,高蛋白、高不饱和脂肪酸、营养丰富、无肌间刺、易加工,是世界性养殖鱼类,其中大西洋鲑、虹鳟和红点鲑属鱼类等主要养殖鲑科鱼类,一直是水产遗传育种领域的重要研究对象。本文简要叙述了鲑科鱼类遗传育种研究的历史和现状,主要介绍了经济性状遗传参数估计、选择育种、分子遗传与标记辅助育种等方面的研究进展,提出了我国鲑科鱼类遗传育种工作重点研究的方向。     

杂种优势理论技术研究及在鲤鱼遗传育种中的应用

杂种优势是生物界的一种普遍现象,在鱼类养殖中可大幅度提高鱼类产量和改良鱼类品质,有很大的生产应用价值,其理论和技术的研究一直是遗传学家探讨的热点问题。综述了杂种优势的遗传机理、预测方法和遗传力分析,阐述了杂种优势在鲤鱼遗传育种中的应用情况、存在问题和可能的解决方法。     

我国养殖鱼类育种技术概况

我国渔业产量和养殖规模近年来一直居世界首位,但依然缺少高效、优质、抗病力强的养殖品种.如何通过传统育种和生物技术对鱼类进行品种选育和遗传改良,以获得优良性状的苗种,将对促进水产养殖业向高产、优质、持续、健康方向发展具有重要的意义.本文就我国养殖鱼类育种技术研究作一扼要的概述.     

DNA甲基化及其在水产养殖动物中的应用研究进展

DNA甲基化是真核生物基因表达调控的重要的一种表观遗传机制。近年来,随着对水产养殖动物各领域研究的不断深入,DNA甲基化在水产养种动物遗传育种的领域引起了广泛的关注,取得了一些进展。本文简要介绍了DNA甲基化和其检测技术,并从鱼类、贝类、棘皮动物三个方面分别介绍了该技术在这三类动物上的研究进展,为今后水产养殖动物的表观遗传学研究提供参考。     

鱼类育种技术研究进展

我国海淡水鱼类近5 000种,其中海水鱼约占三分之二,淡水鱼约占三分之一,鱼类养殖种类数由60年代的十多种增加到目前的百种左右,养殖产量也得到相应提高。建立先进的鱼类育种技术体系和育种研究创新平台、提高鱼类遗传育种的效果和种苗质量对促进水产养殖业的健康发展具有重要意义。本文阐述了鱼类遗传育种的技术及其当前的发展动态,分析了现代生物技术在鱼类育种中的应用概况,探讨了鱼类遗传育种的发展趋势,旨在为鱼类新品种选育提供理论依据与参考。     

鱼类抗病性育种研究进展

专家们从６０年代开始广泛研究通过遗传改良培育抗病品种，以降低各种鱼病对鱼类生产的威胁。鱼类抗病性育种研究主要集中于两上方面：（１）鱼类抗病能力遗传方差研究；（２）抗病育种的方法研究。目前从这两个角度出发，对抗体水平、血清和粘液的中和活性、应激反应、质量性状、蛋白质多态性及组织相容能力等方面都已有研究，并取得了一些进展。     

DNA分子标记在我国海水养殖动物遗传育种中的应用

DNA分子标记是以脱氧核糖核酸多态性为基础的遗传标记.本文综述了DNA分子标记技术在环节动物、软体动物、甲壳动物、鱼类等我国海水养殖动物中遗传多样性和遗传结构分析、亲缘关系鉴定、品系家系鉴别、构建遗传连锁图谱、数量性状定位等方面的应用.指出了目前DNA分子标记在海水养殖动物遗传改良和辅助育种等研究领域存在的问题,最后对该领域的研究提出展望,以期为海水养殖动物遗传育种研究提供参考.     

Integrating molecular genetic technology with traditional approaches for genetic improvement in aquaculture species

Genetic improvement of aquaculture species offers a substantial opportunity for increased production efficiency, health, product quality and, ultimately, profitability in aquacultural enterprises. Technolo‐gies exist that can be implemented immediately to improve multiple traits that have economic value, while simultaneously accounting for inbreeding effects. Genetic improvement techniques for delivering genetic gain include formal definition of the breeding objective, estimation of genetic parameters that describe populations and their differences, evaluation of additive and non‐additive genetic merit of individuals or families and defining the structure of a breeding programme in terms of mating plans. Novel genetic technologies involving the use of DNA‐based tools are also under development for a range of aquaculture species. These gene marker technologies can be used for identification and monitoring of lines, families and individuals, monitoring and control of inbreeding, diagnosis of simply inherited traits and genetic improvement through selection for favourable genes and gene combinations. The identification of quantitative trait loci (QTL), and direct or linked markers for them, will facilitate marker‐assisted selection in aquaculture species, enabling improvement in economically important traits, particularly those that are difficult to breed for, such as food conversion efficiency and disease resistance.     

Genetic basis of Colossoma macropomum broodstock: Perspectives for an improvement program

Tambaqui, Colossoma macropomum (CUVIER, 1818), is the most farmed fish in Brazil. Endemic to the Amazonas and Orinoco basins, it is currently raised in all Brazillian regions. The lack of basic genetic information on tambaqui broodstock has been one of the problems of improvement programs in the species. The goal of this study is to provide information on the genetic basis of tambaqui broodstock from six fish farms located in three different regions of Brazil for application in improvement programs. Thus, genetic analyses were conducted using 15 microsatellite loci. We observed that the broodstock of Biofish (NortB), Prosperidade (NortP), and Tajá (NortT) presented loss of genetic variability. However, their genetic diversity values are higher when compared with the broodstock from the AquaBrasil (improved, NortA) project, Brumado (SoutB), and Departamento Nacional de Obras Contra a Seca (DNOCS) (NorthD), respectively. Furthermore, the broodstock of DNOCS needs to be renovated or increased, and the AquaBrasil individuals need to be better evaluated to verify the improvement achieved in the improvement program. Thus, aimed at the improvement of tambaqui production in the fish farms analyzed, we recommend increasing the population size of the broodstock to avoid inbreeding.     

Genetic improvement for important farmed aquaculture species with a reference to carp,tilapia and prawns in Asia: achievements,lessons and challenges

This study provides an overview of successful genetic improvement programmes for important farmed aquaculture species in Asia, with a focus on lessons and experiences gained as well as challenges remaining. In both fish and prawns (Macrobrachium rosenbergii), conventional selective breeding approaches have resulted in significant improvement in productivity, with genetic gains ranging from 8 to 12% per generation. Selection for high growth has also brought about beneficial changes in fillet weight of fish and edible meat in prawns without detrimental effects on flesh quality attributes and fitness‐related traits. Genetically improved animals show remarkable vigour and high adaptation to a range of culture environments/conditions in Asian countries. Despite these successes, however, the conduct and practical implementation of such breeding programmes still present several challenges. These include the expansion of breeding objectives, management of inbreeding in closed‐selection populations, controlling the effects of genotype by environment interactions, simultaneous production of large number of full‐ and half‐sib families for species with asynchronous spawning behaviour, maintaining pedigree records, dissemination of the improved strains for widespread production, as well as a reluctance by many to carry out systematically designed genetic improvement for aquatic animal species. There are also challenges with regard to the application of genomic information in genetic enhancement programmes and the development of genetically improved strains in response to climate and environmental changes. In this study, each of these challenges is discussed and solutions are proposed to increase efficiency of future genetic improvement programmes for economically important aquaculture species.     

An Assessment of Hatchery Cohort Growth Rates of South African Abalone,Haliotis midae,Across Four Commercial Environments

The abalone, Haliotis midae (commonly referred to as “perlemoen”), is an important aquaculture species in South Africa, accounting for the highest percentage of total aquaculture production revenue. The industry largely makes use of wild, undomesticated broodstock and thus a consortium of top producers was formed to develop a genetic improvement program to increase efficiency and sustainability of the industry. As such, the current study aimed to evaluate growth trait performance (wet weight and shell length) of four hatchery‐derived cohorts of South African abalone, across four differing production environments. No significant cohort‐by‐location effects were found for weight and length traits; however, differences were detected between respective cohorts and locations. It is concluded that a single synthetic population comprised of all hatchery cohorts under a single breeding goal is suitable for production at all test locations. Furthermore, advances in artificial reproductive technologies, genetic markers, and individual identification hold promise for genetic improvement of the species.     

Toward Coordination and Funding of Long-Term Genetic Improvement Programs for Striped and Hybrid Bass Morone sp.

The productivity and profitability of striped and hybrid bass Morone sp. aquaculture would be enhanced by genetic improvement of cultured stocks. To date, genetic improvement of cultured bass stocks largely has been limited to interspecific hybridization and ploidy manipulation, techniques which are aimed at short-term genetic gains. Upon domestication, long-term improvement of striped or hybrid bass can be approached. Lines of striped bass and other Morone species can be selected for rapid growth, stress tolerance, disease resistance, combining ability, or other traits. Improved lines can be crossed to produce superior hybrids or crossbreds, or manipulated to produce superior triploid or transgenic stocks. Current breeding projects are limited in size, and coordination of breeding activities among groups would be advantageous. Faced with the likelihood of limited government funding, long-term genetic improvement of Morone species might be supported by the industry through a fund receiving a small percentage of the proceeds from sales of cultured Morone products.     

Molecular markers and their application in genetic diversity of penaeid shrimp

Penaeidae is a family of shrimp, and it contains many species of economic importance, such as the tiger prawn (Penaeus monodon), white leg shrimp, Atlantic white shrimp and Indian prawn. Identification and population genotype structure of penaeid shrimp have been enhanced by molecular markers that can be classified into three types, namely allozyme, mitochondrial and nuclear markers. The widely used mitochondrial DNA markers are 12S rDNA, 16S rDNA, cytochrome b and control region. Random amplification of polymorphic DNA, amplified fragment length polymorphism, restriction fragment length polymorphism, single-stranded conformational polymorphism and microsatellites are the most commonly used nuclear markers for DNA fingerprinting. Molecular markers play a crucial role in penaeid shrimp to evaluate phenotypic and genetic variation, assess demographic bottleneck, study natural population structure, compare wild and hatchery populations, preserve genetic biodiversity, construct chromosome maps and detect whether genetic tag propagation–assisted rehabilitation programs are effective. Increase in the number of molecular markers, construction of high-density genetic maps and implementation of genomic resources (including genome sequencing) are expected to provide tools for the genetic improvement in these aquaculture species through marker-assisted selection. Molecular markers are versatile tools for the identification of populations with genetic crisis by comparing genetic diversities, which helps to establish management units within these threatened species.     

遗传改良对世界水产养殖业发展的推动作用

随着全球水产品养殖产量快速增长，水产养殖业在近二十年间正快速替代捕捞业，成为满足人类对优质蛋白需求极具潜力的生产活动。世界水产品消费量近几十年来快速增长，水产品在人类食物系统中具有越来越重要的地位。遗传改良作为发展水产养殖业的关键环节而备受关注，长期以来，以选择育种和杂交育种为主要的育种方法，以生长速度、成活率等经济性状为主要改良的目标性状，对世界水产养殖业的发展发挥了基础性、先导性和战略性作用。随着人们对优质蛋白需求的不断增加以及“大食物观”概念的广泛普及，将水产品打造为更加高效的食物生产系统是大势所趋。但纵观全球，水产养殖业存在遗传改良种类不多、覆盖面不广、改良性状滞后于产业发展需求等问题，需要加强水产育种技术创新和品种培育，培育更多的遗传改良种，推进水产养殖业高质量发展。本文基于已有研究结果，结合渔业各类统计数据，对世界水产养殖业发展概况、重要养殖种遗传改良情况、水产育种技术应用、目标性状改良以及部分主要人工改良种产量数据进行整理概述，总结发展状况，分析存在问题，以期为水产种业研究以及产业高质量发展提供参考。     

基于线粒体COI基因的马科鱼类DNA条形码研究

为明确中国马鲅科(Polynemidae)鱼类的分类地位,测定了中国7省10个地点马鲅科鱼类3属5种33条COI基因5′端序列,结合GenBank下载的5属16种41条同源序列,共分析了6属20种马鲅科鱼类DNA条形码。结果显示,20种鱼类种间平均遗传距离为19.6%,是种内平均遗传距离0.9%的22倍;其中14种形成了单系分支,支持其物种有效性。四指马鲅(Eleutheronema tetradactylum)和多鳞四指马鲅(E.rhadinum)种间遗传距离(16.0%)是种内平均遗传距离(1.2%)的13倍,支持将二者作为2个独立物种的分类处理。多鳞四指马鲅种内遗传距离(2.3%)大于2%,形成了2个自展数据支持率为99%的分支,分支间遗传距离(4.8%)是分支内平均遗传距离(0.1%)的48倍,表明在中国沿海分布的多鳞四指马鲅有可能存在2个亚种或隐藏种。黑斑多指马鲅(Polydactylus sextarius)与马达加斯加多指马鲅(P.malagasyensis)外部形态极为相似,种间遗传距离仅为1.0%,且在分子系统树上镶嵌混杂为一支,仅根据分子数据结果,推测二者可能为同一物种;但由于没有可检视的标本,也不能排除GenBank序列种名注释中形态鉴定出错的可能。马伦氏多指马鲅(P.mullani)与七丝指马鲅(Filimanus heptadactylus)也混为1支,分支内遗传距离仅为0.1%;如果不是GenBank序列种名注释出错,则二者应为同一物种。GenBank序列中来源于北部湾的六丝多指马鲅(P.sexfilis),则可能是黑斑多指马鲅的错误鉴定。     

Microsatellite genetic variation in wild and hatchery populations of the sea cucumber (Apostichopus japonicus Selenka) from northern China

Farming of the sea cucumber Apostichopus japonicus (Selenka) started 20 years ago and is still in rapid expansion in China. In order to assess the genetic status of both wild and cultivated stocks of this species, we used eight microsatellite markers to estimate the level of genetic diversity within five hatchery stocks and two wild populations of A. japonicus, and compared the degree of genetic differentiation between them. High levels of polymorphism were observed over all loci. The mean alleles and expected heterozygosities over the seven stocks were 10.4–12.3 and 0.735–0.783 respectively. The results of the microsatellite survey provide no evidence to show that hatchery practice of the sea cucumber in China to date has significantly affected the genetic variability of the cultured stocks. Significant differentiation was found between most pairs of the hatchery stocks and wild populations (F_st range: 0.008–0.036), and no obvious difference was detected between the wild populations (F_st=0.008). The information on the genetic variation and differentiation obtained in this study can be applied for future genetic monitoring of A. japonicus aquaculture stocks and will be useful for future genetic improvement by selective breeding, and for designing suitable management guidelines for these genetic materials.     

应用时间序列分析模型对大菱鲆选育F1优良家系发育的动态研究

根据Box-Jenkins建模原理,采用ARIMAR(p,d,q)模型,以大菱鲆选育F1优良家系为研究对象,应用时间序列分析方法对在3～27月龄间不同发育阶段体重的生长速度进行动态模拟,建立各家系的预测模型。结果表明,家系E♂1×E♀2和F♂2×E♀4符合ARIMAR(2,0,0)模型(2个家系的模型都不含常数项),家系F♂4×N♀3、E♂2×F♀1和F♂1×F♀4符合ARIMAR(1,0,0)模型(3个家系的模型都不含常数项),且所建模型的残差均为白噪声。由此预测出27～27.5及27.5～28月龄各家系体重生长速度,经与相应实测数据的验证说明,5个家系各自所建模型在一定程度上能够反映大菱鲆体重生长速度的动态变化过程,对各家系体重生长速度的趋势预测有一定的适用性。通过对每一家系后期生长速度的预测,结合前期生长速度的实测值,综合分析体重生长速度的动态变化,为在大菱鲆选择育种过程中确定最佳选择时间提供理论依据。