中国明对虾种质资源研究现状与保护策略

中国明对虾主要分布在黄、渤海水域,是我国重要的渔业资源之一。由于忽视对中国明对虾种群自然状态下遗传多样性的监测,缺乏对种质资源进行长期的、有效的管理,造成黄、渤海野生群体的遗传多样性下降。目前,随着对种质资源的研究越来越受到人们的关注,中国明对虾种质资源以及种群遗传学已成为研究热点,种群保护也已提到议事日程。这些研究工作的开展将为中国明对虾良种选育提供理论依据,相信随着研究工作的继续深入,人们会更好、更有效地利用对虾资源。     

虾类种质资源研究进展

概述了虾类种质资源鉴定和遗传育种研究的进展情况,主要包括应用形态学、同工酶、DNA标记等技术在虾类基因组DNA多态性的检测、物种及品种的分类鉴定,亲缘关系及分子标记辅助育种中的研究和应用.形态学研究易于开展,广泛使用在研究和生产上;同工酶研究操作简便,能在一定程度上反映基因多态性;DNA标记可以准确反映不同种群的遗传变异和遗传多样性,目前被广泛使用.但形态学研究缺乏量化指标,同工酶技术反映的多态性较少,DNA标记不能直接和生产相结合,因此多种标记相结合在虾类种质资源研究中具有广阔的应用前景.     

SNP分子标记技术在经济甲壳动物中的应用进展

作为第三代分子标记,单核苷酸多态性标记(SNP)具有丰富度高、密度大、稳定性强、共显性等特点,成为目前虾、蟹等经济甲壳动物中应用最广泛的分子标记技术。本文对经济甲壳动物中SNP技术的发展及其在高密度遗传连锁图谱的构建、种质资源遗传多样性分析、分子辅助育种等方面的应用进展进行了综述,并提出了未来有待加强的研究方向,以期为经济甲壳动物种质资源的开发和利用提供理论指导。     

水产动物种质创制新技术及在海参、海胆遗传育种中的应用

随着现代遗传育种理论和生物技术的不断发展与创新,水产育种技术也开始从传统的选择育种、杂交育种技术,逐渐向与分子标记辅助育种、细胞工程育种、全基因组选择育种、分子设计育种、性别控制、基因转移以及基因编辑等现代分子辅助育种技术相结合的方向发展。虽然,我国水产种业已经形成并蓬勃发展,但仍存在良种覆盖率低、研究深度不够等问题和挑战。本文在国内外研究的基础上,重点综述了棘皮动物(海参和海胆)的种质资源概况、水产养殖育种新技术及在经济棘皮动物中的应用,并对海参、海胆养殖业提出了建议,以期为合理开发我国经济棘皮动物种质资源提供参考,推动水产养殖业绿色发展。     

中国水产科学研究院南海水产研究所研究员周发林 斑节对虾正加紧做良种制种和苗种扩繁

正周发林中国水产科学研究院南海水产研究所研究员、广东省现代农业产业技术体系虾蟹创新团队良种与良法创制岗位专家。主要研究方向为水产种质资源和遗传育种,在海水鱼类种质保存及遗传多样性研究、斑节对虾全人工繁育和遗传育种研究等方面取得了多项公认的突破性成果,培育出包括斑节对虾"南海1号"在内的多个对虾新品种(系)。     

SSR在水产养殖中的研究进展

为深入了解简单重复序列(Simple sequence repeats, SSR)分子标记在水产养殖中的应用情况,为今后开展水产养殖动物的分子标记辅助育种,综述了SSR的开发方法以及SSR在种群的遗传多样性分析、数量性状的定位、DNA指纹图谱构建、遗传连锁图谱构建等方面的研究进展。SSR分子标记在水产养殖动物的种质鉴定、遗传距离分析、分子标记辅助育种等方面具有广阔的应用前景。     

养殖对虾新品种培育技术研究进展

本文介绍了国内外有关养殖对虾遗传改良研究的现状，并对选择育种、杂交育种、多倍体育种、人工雌核发育和转基因育种等手段研究进展进行了详细分析。提出利用现代生物学的新技术、新方法改造传统养殖业，将传统的育种研究技术与现代生物学技术相结合，加快培育优质、抗逆对虾养殖新品种是从根本上解决困扰对虾养殖业发展的重要研究方向。     

鱼类环境耐受性与抗逆性育种研究进展

随着高密度集约化水产养殖业的发展，溶解氧、水温和氨氮等水环境因子胁迫已成为制约渔业高质量发展的限制性因素，抗逆水产新品种的培育成为重要的解决途径之一。本文综述了鱼类对温度、低氧、氨氮、亚硝态氮、盐碱胁迫的响应机制，以及环境耐受性鱼类新品种的育种现状，提出充分利用第一次全国水产养殖种质资源系统调查结果发掘优异种质资源，建立高通量表型和基因型精准鉴定技术，深入解析鱼类响应环境因子胁迫的机制，利用分子标记辅助育种、全基因组选择育种、基因编辑育种和分子设计育种等现代分子育种技术进行高效精准抗逆新品种的培育，为鱼类抗逆性新品种培育提供参考。     

中国明对虾抗白斑综合症病毒分子标记的筛选

采用随机扩增多态性DNA(RAPD)技术对经过连续4代选育的抗白斑综合症病毒(WSSV)中国明对虾(Fenneropenaeus chinensis)(174)及未经选育的与174来源相同的中国明对虾野生群体(HB)进行分析,以期筛选出与抗病性状相关的分子遗传标记,为进一步的基因定位以及中国对虾的种质资源保护和分子标记辅助育种提供有力的技术支撑和理论依据。共进行220个RAPI)单引物和114对双引物的检测,产生标记数目共计2439个。依据标记在群体中出现的频率和变化规律,共筛选出5个可能与抗病相关的特异性标记,对这些特异性标记进行测序并将测序结果进行BLAST分析,发现测得片段的序列与数据库中序列的相似性较低,未能找到与所测序列同源性较高的功能基因。这与利用AFIP技术分析的结果一致。由于选育过程施加人工选择,推论这些特异性标记虽不是抗WSSV分子标记,但可能与抗病性状密切相关。     

斑鳢基因组中微卫星分布特征及野生种群遗传结构分析

斑鳢(Channa maculata)是华南地区的本土经济鱼类,也是杂交鳢的亲本之一。养殖个体逃逸可能会对野生种群产生影响,存在种质混杂的风险,亟须开展野生资源的遗传背景分析。该研究分析了斑鳢基因组中微卫星标记的分布特征,筛选获得20个多态性位点构建多重PCR体系,对广州、化州、江华、南宁、阳江和邵武6个野生群体的遗传多样性和遗传结构进行了分析。结果显示,6个野生群体各位点的等位基因(Na)为3~28、有效等位基因(Ne)为1.28~14.88、观测杂合度(Ho)为0.10~1.00、期望杂合度(He)为0.14~0.95以及多态信息含量(PIC)为0.13~0.95。UPGAM系统进化树结果显示,化州和福建种群遗传关系最近,化州和江华种群遗传关系最远。该研究结果将为斑鳢的遗传监测和亲缘关系鉴定提供技术支持,为斑鳢种质资源养护及管理提供参考。     

微卫星标记技术在虾类分子遗传学研究中的应用

微卫星是一种新型的分子标记。本文分析总结了近年来微卫星技术在虾类遗传多样性、亲缘关系鉴定、遗传结构和遗传变异及遗传连锁图谱构建和基因定位等方面的研究进展情况。     

文蛤转录组中微卫星位点生物信息分析#br#

采用生物信息学方法分析了文蛤(Meretrix meretrix)转录组中微卫星序列(简单重复序列,simple sequence repeat)的分布规律。结果表明:在文蛤转录组SSR中,单碱基重复序列的数量最多,有3001个;其次为三碱基和四碱基重复序列,分别为2254和2200个;二碱基重复序列1052个;五碱基重复序列332个;六碱基重复序列最少,仅13个。文蛤转录组SSR共包含26种重复基元,其中优势基元为单碱基重复A/T有2809个,其次为三碱基重复AAC/TTG有907个,四碱基和二碱基重复中的AAAC/TTTG和AT/TA分别有588和561个,说明文蛤转录组微卫星位点的分布对A/T具有偏好性。文蛤完整SSR的平均长度为18.34 bp,长度分布在12~20 bp,约占41%。研究结果将为研究文蛤SSR标记开发、群体遗传多样性、遗传连锁图谱、种质资源鉴定和分子遗传育种等后续研究提供基础数据。     

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.     

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.     

构建鲤现代种业的核心技术

对于任何一个农业物种而言,现代种业核心技术包括3个方而：收集与创制最优良的种质资源、建立先进实用的育种技术、方便的可最大化利用上述资源的数据库及网站。针对鲤这个水产养殖种,黑龙江水产研究所及合作单位经过30多年的研究积累和创制了抗寒能力强、生长速度快、肉质好的三大系列种质,在此基础七已经培育出6个水产新品种;构建了基于亲本遗传距离的分子育种技术,并在常规育种技术的使用过程中增加了统计分析和染色体操作技术,如BLUP技术、雌核发育技术等,将现代育种技术充分地运用于鲤的品种培育之中;同时建瓿了涵盖表型、生物学特征、一般遗传参数的鲤种质数据库和涵盖基因、标记及经济性状QTLs的鲤基因组数据库,使鲤具备了现代种业需要的生物学、遗传学、基因组学的完整数据库。综上所述,初步构建了鲤现代种业的核心技术。     

Breeding for disease resistance of Penaeid shrimps

Diseases are a major constraint on the intensive production of shrimps. Conditions in production ponds favour disease development, and epidemics of several previously unreported diseases have occurred and caused severe losses. When elimination, eradication or cultural control is difficult, selective breeding for host resistance to the pathogen may be an attractive option for disease control. However, host resistance is not a panacea and should only be considered when (a) the disease causes severe damage (b) there are no other existing simple cost effective control measures and (c) there is demonstrable genetic variation in resistance and this is not coupled with an excessive level of negative associations with other desirable characteristics. Shrimp have only recently been domesticated and breeding for resistance only began in the mid 1990s; there is limited experience with shrimp breeding in particular and crustaceans in general. Consequently, the principles and concepts behind breeding programmes are based largely on experiences with other species in both the plant and animal kingdoms. Commercial growers now seed ponds with shrimp populations selected for resistance to Taura Syndrome Virus with excellent results, whilst up to now development of White Spot Syndrome Virus resistant populations has been an elusive goal. The original TSV resistant populations were developed using simple mass selection techniques (Colombia). In later generations family based selection has been applied on populations, which initially had survival rates of about 30%, with care taken to reduce inbreeding and loss of genetic variation. This suggests that when the original populations have a reasonable level of resistance, and straightforward, effective selection protocols exist, it is relatively simple to breed for resistance. With catastrophic diseases, such as WSSV, which cause mortalities of 98% or more the frequency of resistance is low and it is suggested that for theoretical reasons single gene, rather than polygenic, resistance is likely to develop. The low frequency of resistance genes in breeding populations may cause genetic bottlenecks which will greatly reduce the genetic variation in the populations. In order to maintain the genetic variation the genes from the small numbers of survivors should be introgressed into populations with broader genetic variability. Furthermore, in order to minimize the probability of breakdown of resistance pyramiding of resistant genes on different loci would be advantageous.Genetic variation in resistance may be encountered either in the initial base populations or may spontaneously arise due to mutations or new recombinants. With extremely prolific species such as shrimps, millions of animals can readily be screened for survival and hence resistant mutants or recombinants may be identified. Once genetic variation has been detected the most appropriate breeding methodology will depend on the nature of both the resistance and the disease or diseases that are of interest to the producers.     

中国鲤育种的主要方法、遗传解析及展望

水产种业是水产养殖业发展的基础,是渔业战略性、基础性核心产业,也是保障未来养殖业绿色、健康发展的核心竞争力。随着水产业全球化、市场化的发展,我国种业正面临着前所未有的机遇与挑战。特别是随着生物技术的快速发展,水产育种也由传统的选择育种和杂交育种,发展至细胞工程育种、分子标记辅助育种、全基因组选择育种、分子设计育种和基因组编辑等精准设计育种。水产动物重要经济性状的基础研究及其遗传改良技术的创建驱动着我国水产种业的蓬勃发展,截止2022年,通过全国水产原种和良种审定委员会审定并由农业农村部公告的水产新品种就有266个,其中鲤新品种数量最多,为31个,表明鲤育种工作卓有成效。本文重点回顾了我国鲤的种质和基因组资源现状,鲤的主要品种及其育种方法;简要介绍了鲤生长、抗病、体色、饲料转化率等经济性状关联的遗传研究进展,并由此提出了新时代背景下鲤种业的发展方向和措施建议,以期为我国鱼类育种提供借鉴。