长牡蛎3种壳色家系间杂交子代生长和存活比较

为了利用杂种优势培育长牡蛎优良新品种,实验以3种不同壳色长牡蛎家系(白色/W、黑色/B、紫色/P)为材料,采用3×3完全双列杂交法,建立了3个自交组合和6个正反杂交组合,分析了各实验组幼虫期和养成期的生长、存活以及杂交子代的杂种优势。结果表明,浮游幼虫期,杂交组PB表现出显著的生长优势;与自交组相比,各杂交组均有着较高的幼虫存活率;在幼虫存活率方面,所有杂交组均有较高的杂种优势率。在养成期,紫壳色自交组的壳高显著大于白壳色和黑壳色自交组;6个杂交组中,PB的壳高生长最快,BP次之,PW、WP的生长最慢;各杂交组与自交组的成活率差异均不显著;杂交组BP及其反交组PB的壳高、壳长、总重和存活率的杂种优势率分别介于3.71%~15.27%、-2.00%~13.10%、11.23%~41.56%、-2.77%~9.83%,其他4个杂交组在整个养成阶段没有表现出杂种优势。     

Comparison of low temperature adaptation ability in three native and two hybrid strains of the rotifer <Emphasis Type="Italic">Brachionus plicatilis</Emphasis> species complex

The low temperature adaptation ability of five selected strains of the Brachionus plicatilis species complex, i.e., three native strains [ Japanese (NH1L), Australian, German] and two hybrid strains [♀NH1L and ♂Australian (N × A) and ♀NH1L and ♂German (N × G),was investigated in terms of life history traits, reproductive characteristics, and mobility under different thermal conditions (12 and 25 °C). The life history traits of these five strains included a longer lifespan, reproduction period and generation times at 12 °C than at 25 °C, combined with reduced lifetime egg and offspring production. At 12 °C, the intrinsic rate of natural increase was higher in NH1L and N × A strains. Reproductive characteristics determined at 12 °C by batch culture showed active population growth for NH1L and N × G strains, while no resting egg production was observed in all of the strains tested. The ratio of swimming rotifers at 12 °C was monitored every hour for 6 h (short term) and every day for 10 days (long term). In the short-term study there was a 81% ratio of swimming rotifers of the NH1L strain, while other strains exhibited low swimming ratios (<60%). In the long-term study NH1L and two hybrid strains showed a >75% swimming ratio from the initial day of the study. These results suggest that outcrossing of rotifer strains is useful to obtain live food resources for the larviculture of cold water fish.     

三个不同品系中华鳖形态差异分析

通过测量中华鳖(Pelodiscus sinensis)淮河品系(3龄)、黄河品系(8月龄)和日本品系(8月龄)的10项形态参数,对不同品系和性别的形态差异进行分析。主成分分析表明,3个品系4个主成分的累计贡献率为80.5%,其中第1主成分是中华鳖的体型因子,贡献率最大,3个品系的形态差异主要体现在体型上。通过逐步判别法建立了3个品系的判别函数,淮河、黄河和日本品系的判别准确率分别为91.7%、75.0%和73.8%,淮河鳖的形态与其他品系的中华鳖存在较大的差异。3个品系中不同性别的判别分析显示,淮河品系中华鳖雌雄判别准确率也较高,综合判别率为88.3%,判别效果最好,建立的判别函数可初步用于不同品系不同性别中华鳖的鉴定。中华鳖形态特征的差异分析为今后中华鳖种质资源鉴定和新品种(系)的选育提供了参考依据。     

AFLP-based genetic linkage map of marine shrimp Penaeus (Fenneropenaeus) chinensis

This paper presents the genetic linkage map of the Chinese shrimp Penaeus (Fenneropenaeus) chinensis constructed with 472 AFLP markers. A hundred F₁ progeny from an intercross between a female from the new variety “Yellow Sea No. 1” and wild caught male used for the mapping study. Two separate maps were constructed for each parent. The female linkage map consisted of 197 marker loci forming 35 linkage groups and spanned a total length of 2191.1 cM, with an average marker space of 13.5 cM. The male map consisted of 194 marker loci mapped to 36 linkage groups and spanned a total length of 1737.3 cM, with an average marker spacing of 11.0 cM. The level of segregation distortion observed in this study was 12.2%. The estimated genome length of P. chinensis was 3150.3 cM for the female and 2549.3 cM for the male, respectively. The observed genome coverage was 69.6% for the female and 68.1% for the male map. The linkage maps constructed in this study provide basic information for further linkage studies on Chinese shrimp, and more importantly, the construction of the maps are part of the work of the genetic breeding programs which will be used for growth discovered in the QTL analysis of P. chinensis.     

Offspring Growth in a Diallel Crossbreeding with Three Strains of Nile Tilapia Oreochromis niloticus

Abstract— A complete diallel crossing of three strains, Stirling, Korean and Local, was used to evaluate heterosis of intraspecific crossbreeding on early growth of Nile tilapia Oreochromis niloticus . All possible F-1 hybrid offspring were obtained and their growth rates to 90 d were compared. The specific heterosis for F-1 hybrids in Stirling × Korean, Stirling × Local and Korean × Local crosses were 7.61, 5.63 and 7.70 for weight, and 0.47, 0.26 and 0.55 for length, respectively. The purebred Stirling strain showed better growth than the other two strains (P < 0.05). When growth of F-1 hybrids was compared between sexes, males grew more rapidly than females (P < 0.05). However, no differences were observed in growth of male or female between hybrid groups. Purebred males in the Stirling strain were slightly heavier than those in the Korean and Local strains, and Local × Stirling, Korean × Local and Local × Korean crosses. However, in purebred females Stirling was superior to Korean, but not the Local strain and all F-1 hybrid crosses. Implications to choose the appropriate strains for developing a breeding program of tilapia are also discussed.     

牙鲆家系亲权鉴定的微卫星DNA标记分析

为准确进行不同家系的亲权鉴定,筛选具有高亲本排除概率的微卫星DNA标记,从牙鲆选育基础群体中挑选性腺发育良好的雌雄亲本各10尾建立全同胞家系10个,从独立饲养的每个家系中随机选取30尾个体组成系谱结构已知的家系群体,从混合培育的子代群体中随机选取200尾个体组成系谱结构未知的混合群体。48个微卫星DNA标记选自牙鲆第二代遗传连锁图谱,且均匀分布于24个连锁群上,每个连锁群2个标记。家系群体的遗传分析结果发现,10个拥有丰富遗传多态性的微卫星DNA标记表现出高的亲本排除概率,其Excl1和Excl2的范围分别为0.655~0.719和0.792~0.837。随鉴定所用微卫星DNA标记数目的增加,累计排除概率逐步升高。当使用8个微卫星DNA标记鉴定时,累计排除概率达到100%。利用这些标记开展混合群体的亲权鉴定,显示共有13个雌雄个体参与繁殖过程,不同亲本配组产生的后代数量存在差异,亲本与后代群体之间的各项遗传学统计指标不存在明显差异。研究表明,筛选出具有高亲本排除概率的微卫星DNA标记能够有效进行牙鲆家系的亲权鉴定,可以作为今后开展家系选育与DNA分子标记联合育种的候选标记。     

Study of sex ratio in progeny of a complex Oreochromis hybrid,the Florida red tilapia

This paper reports a study on the progeny sex-ratio distribution in the Florida red tilapia. This hybrid originated as a cross between O. mossambicus male and O. urolepis hornorum female, which was then crossed with O. niloticus and O. aureus in order to improve its growth rate and its resistance to low temperature. We have studied the sex-ratio of 111 progenies from 46 females and 12 males, where the male percentage varied between 5% to 89%. The analysis of distribution showed three groups characterised by a mean male percentage of 26.7 ± 9.8; 50.0 ± 8.9 and 70.3 ± 5.5%. The stability of sex ratios in repeated single pair matings and the parental influence on progeny sex ratios obtained are in agreement with a polygenic basis of sex determination in this complex hybrid.     

吉富罗非鱼与奥利亚罗非鱼自繁与杂交 F1遗传特性与抗病力分析

以吉富罗非鱼与奥利亚罗非鱼为繁育亲本,采用完全双列杂交繁育4组F1,将初始规格基本一致的4组罗非鱼饲养100 d后,运用“加性-显性”遗传分析模型,分析了4组F1罗非鱼8个生长相关性状杂种优势、遗传效应以及与性状间的相关性.结果表明:(1)F1群体平均优势为0.129 4～0.368 4.除尾柄长超亲优势较大外,其他性状的群体超亲优势较小或表现出负向超亲优势.(2)8个性状的广义遗传率(HB)为0.714 2～0.995 3,表明加性效应和显性效应对性状的遗传变异影响极显著(P＜0.01).除尾柄长外,其他性状的狭义遗传率(HN)介于0.469 4～0.737 9,表明加性遗传方差在表型方差中所占比率较高.(3)体质量、全长、体长、体高、体宽、头长、尾柄长、尾柄高性状之间表型相关在0.776 6～0.999 7范围内,而遗传相关在0.994 1～1.000 0之间,表明这些性状间都存在极显著的正相关.取样结束后,采用3.95×106 CFU/mL的海豚链球菌菌液进行腹腔感染,吉富罗非鱼自繁组F1代12 h后出现死亡,而奥利亚罗非鱼自繁组F1192 h后才出现死亡.384 h后,吉富罗非鱼自繁组F1死亡率为40％,正反交组F1分别为20％和23.3％,奥利亚罗非鱼自繁组F1死亡率最低,为6.67％.研究结果表明,除尾柄长外,杂交F1的其他性状不具备超亲优势,然而杂交可以提高选育后代的抗病力.     

Growth and salinity tolerance in hybrids within Salmo sp. and Salvelinus sp.

Attempts were made to complete all possible interspecific hybrid crosses between Atlantic salmon (Salmo salar), rainbow trout (Salmo gairdneri), brook trout (Salvelinus fontinalis), lake trout (Salvelinus namaycush), and Arctic char (Salvelinus alpinus). Survival was appreciable only in (giving female first) lake × brook, salmon × char, brook × char and char × brook hybrids. Growth rates over a weight increment of 3–30 g averaged 2.14% wet weight/day for all species and hybrids (14.5–17.0°C — excess rations). The highest growth rate, 2.74%, was obtained with the brook (female) × char (male) hybrid and the lowest, 1.63%, in lake trout. Salmon (female) × char (male) hybrids grew faster than salmon; brook trout (female) × char (male) hybrids grew faster than brook trout. Salmo species grew no faster than Salvelinus species but became silvery and had greater salinity tolerance at a smaller size and earlier age. Intergeneric hybrids between female Salmo spp. and male Salvelinus spp. more closely resembled the female parent in processes related to smoltification (silvering and salinity tolerance).     

Preliminary Results on Rearing of Sparus Aurata × Pagrus Pagrus Hybrids. Performance Comparison With the Parental Species

Hybridization between gilthead sea bream, Sparus aurata, and red porgy, Pagrus pagrus, was undertaken and viable hybrids were produced by an artificial hormonal-induced cross. The hybrids, from the cross of female red porgy and male gilthead sea bream (Pp × Sa), survived through the yolk-sac larval stage. The hybrids produced from the cross of female gilthead sea bream and male red porgy (Sa × Pp) presented higher mortality in the larval stage (98.4%) compared to gilthead sea bream (80.0%) and red porgy (92.5%). Afterwards, the Sa × Pp hybrid was compared to the offspring of its parental species under the same rearing conditions (tanks of 500 l capacity, natural light, ambient temperature, self-feeding with commercial feed) in a 40–week experiment. In this comparative study, the Sa × Pp hybrid had intermediate mortality rate (6%), compared to gilthead sea bream (0%) and red porgy (21%). The growth profile of this hybrid resembled the slow growing phases of its parents (red porgy in warm period and gilthead sea bream in cold period). The feed conversion ratio between fish forms was not significantly different (1.54–1.84 in the Sa × Pp hybrid, 1.53–1.56 in the maternal species and 1.33–1.40 in the paternal one). The body weight variation in the Sa × Pp hybrid was quite high (31.7–37.9%), compared to that in gilthead sea bream (19.7–24.7%) and red porgy (18.0–31.3%). With respect to body coloration, the Sa × Pp hybrid was distinguishable and classified into groups of red porgy-like (55.1%), gilthead sea bream-like (40.6%), and intermediate forms (4.3%). The preliminary results of this study proved that the produced Sa × Pp hybrid had too low a performance for aquaculture use, but the interesting consequent hereditary potential could be a useful tool in fish hybridization practice.     

Genetic comparison of experimental farmed strains and wild Icelandic populations of Atlantic cod (Gadus morhua L.)

Microsatellite DNA loci and the Pantophysin locus (Pan I) were used to investigate levels of genetic diversity within farmed strains of Atlantic cod Gadus morhua and to compare them with the wild source population. A total of 282 farmed samples originating from a spawning ground off the south-west coast of Iceland were sampled in the years 2002 and 2003, and 258 wild cod were collected at the same spawning ground in the same years. The farmed strains exhibited a lower mean number of alleles and allelic diversity than the wild samples at the microsatellite loci. Significant differences were observed between wild and farmed samples both in allele and genotype frequencies at the Pan I locus. We argue that the genetic divergence of wild and farmed samples of Atlantic cod may be due to a small number of effective founding breeders contributing to the genetic variation of the farmed strains, inducing a reduction in allelic diversity. We discuss the potential effect of breeding practices on the genetic diversity of Atlantic cod.     

Inheritance pattern of chloroplast and mitochondrial genomes in artificial hybrids of Porphyra yezoensis (Rhodophyta)

ABSTRACT:   To investigate inheritance of chloroplasts and mitochondria (organelles) in the marine red alga Porphyra yezoensis , cleaved amplified polymorphic sequence (CAPS) profiles of the two strains, TU-2 and KGJ, as parental gametophytes and 44 hybrid sporophytes (i.e. female of TU-2 and male of KGJ) were examined. A carbamyl phosphate synthase small subunit gene ( carA ) and ribosomal protein S11 gene ( rps11 )-small subunit ribosomal RNA gene ( rns ) spacer region were used as molecular markers for the chloroplast and mitochondrial DNAs, respectively. Thirty-eight of 44 (86.4%) conchocelis colonies showed maternal banding patterns, five (11.4%) colonies showed biparental bands and one (2.2%) colony showed paternal bands in CAPS analyses both with chloroplast and mitochondrial markers. These results suggest that organelles of P. yezoensis are inherited uniparentally from the female parent.     

A genetic linkage map of the Japanese flounder, Paralichthys olivaceus

We report the first genetic linkage map of the Japanese flounder (Paralichthys olivaceus) constructed with 111 microsatellite markers and 352 AFLP fragments. The parental male linkage map consisted of 25 linkage groups while the female map consisted of 27 groups, with an average resolution of 8 and 6.6 cM, respectively. We have identified linkage among 96% of the markers and the total map length was estimated to be around 1000–1200 cM. This study reports the first low-density linkage map for the Japanese flounder and describes differences in sex recombination. Recombination rates were higher in male flounder compared to the female (7.4:1), a rare condition among vertebrates. This map is a starting point for the mapping of single loci and quantitative traits in flatfish species.     

菲律宾蛤仔福建与广东群体的双列杂交

2015年9月–12月,以菲律宾蛤仔福建养殖群体和广东野生群体子一代为亲本,开展了双列杂交实验,建立了两个自交组和两个杂交组,研究了杂交子代幼虫和稚贝的生长与存活的杂种优势。结果显示,各实验组均有较高的受精率和孵化率,但无显著差异。总体上,幼虫期的生长受母体效应影响显著,稚贝期的生长杂交效应主要受交配方式影响。相反,幼虫期的存活受配对方式影响最显著,稚贝期的存活受卵源影响显著。在幼虫期,杂交组与自交组在生长和存活方面差异不显著。在稚贝期,生长表现出明显的杂种优势,壳长和壳高在30日龄以后,正反交组的平均生长速率显著快于自交组。在40日龄时,壳高和壳长总杂交优势值达到最大,分别为25.64和27.00。这可能是因为杂种优势的表达具有时期差异性。在幼虫期,福建自交组表现出最高的存活率,为36.45%±1.85%;稚贝期,广东自交组存活率最高,为52.27%±2.13%。在幼虫期和稚贝期的存活率方面,未观测到杂种优势,这可能是由于两个杂交亲本群体与存活相关的基因频率无差异或者检测次数较少所致。     

RAPD and microsatellite analysis of diploid gynogens from allotetraploid hybrids of red crucian carp (Carassius auratus)×common carp (Cyprinus carpio)

Genetic variation was comparatively analyzed between the artificially induced diploid gynogen population from F₁₀ allotetraploid hybrids of red crucian carp (♀) (Carassius auratus red var., 2n=100)×common carp (♂) (Cyprinus carpio L., 2n=100) and the normal F₁₀ allotetraploid hybrid population used as the control, using random amplified polymorphic DNA (RAPD) assay and microsatellite analysis. The specific 600-bp fragment for diploid gynogen population was detected by S45 and the specific 900-bp fragment for allotetraploid F₁₀ hybrid population was detected by S134. The results from RAPD assay and microsatellite analysis were in agreement with each other, that is to say, the diploid gynogens presented lower level of polymorphism than allotetraploid F₁₀ hybrids. Furthermore, as expected, microsatellite analysis revealed more detailed information on genetic diversity than RAPD assay. The mean percentage of polymorphic loci (12.71%) and Shannon's index of phenotypic diversity (0.25) from RAPD data for diploid gynogen population were significantly lower than those (30.69% and 0.63, respectively) for F₁₀ allotetraploid hybrid population. The mean number of alleles per microsatellite locus (1.73) in diploid gynogen population was considerably lower than that (2.55) in F₁₀ allotetraploid hybrid population. The average observed (0.36) and expected heterozygosity (0.26) in diploid gynogen population were lower than those (0.58 and 0.40, respectively) in F₁₀ allotetraploid hybrid population, indicating that the diploid gynogens presented lower genetic diversity than the allotetraploids. In addition, the mean effective number of alleles at 11 microsatellite loci (1.60) in diploid gynogen population was lower than that (1.88) in F₁₀ allotetraploid hybrid population. The significant differences between two populations in the average observed and expected heterozygosity, mean number of alleles and effective number of alleles, suggested that the effect of gynogenesis resulted in rather higher genetic homogeneity in diploid gynogens. The comparative RAPD analysis of diploid gynogens and their parents was performed with 34 primers. The identical RAPD pattern was detected between diploid gynogens and their female parent, however, some clear specific RAPD bands were detected between diploid gynogens and their male parents, but not detected in their female parent. The result indicated that heterologous genetic material had incorporated into diploid gynogenetic fish (G₁).     

Genetic characterization and gonad development of artificially produced interspecific hybrids of the abalones, Haliotis discus discus Reeve, Haliotis gigantea Gmelin and Haliotis madaka Habe

Hybridization among abalone species has been suggested as a possible means to increase their growth rates for aquaculture. As a first step to test the usefulness of the hybrids of Japanese abalone species (Haliotis discus discus, Haliotis gigantea and Haliotis madaka) for aquaculture, we characterized the genetic background and gonad development of hybrids that were produced by artificial insemination. The hybrid status of the resulting offspring was confirmed by assaying 14 allozymes and by RFLP analysis of the 16s rRNA and cytochrome oxidase I (COI) regions of mtDNA using 13 restriction enzymes. Histological examination of the gonads of the hybrids was conducted in comparison with those of the parental species. Cross‐breeding among the three species was conducted successfully in all combinations although with lower fertilization rates (means of 1.3–60.8%) than the parental species (34.3–90%). Crosses between H. discus discus and H. madaka had higher fertilization rates (22.4–60.8%) than those involving H. gigantea (1.3–19.9%). The hybrids were ascertained by the presence of both parental genotypes at the LDH‐A, ME‐A, MDH‐A and GPI loci. The maternal origin of the hybrid mtDNA was confirmed by digestion with DdeI, TaqI, HpaII of the COI region. No polymorphism was observed in the 16S rRNA region. The hybrids had gonadal development and maturity stages similar to the parental species up to fully mature oocytes and sperm. They spawned upon stimulation and produced viable offspring with high fertilization rates and successful development to the juvenile stage in back‐ and homologous hybrid crosses.     

Do strain differences in microalgae alter their relative quality as a food for the rotifer Brachionus plicatilis?

Brachionus plicatilis is used in aquaculture to feed larval fish and crustaceans. It is well established that different prey species alter rotifer productivity. Isochrysis galbana is one microalgal prey that is commonly fed to rotifers, and there are several strains of this flagellate available to aquaculturists. As microalgae strains may differ in their composition and growth attributes, we rigorously examined if growth and biochemical differences in I. galbana strains elicit differences in the growth and biochemical attributes of B. plicatilis. Four I. galbana strains and one strain of the flagellate Nanochloropsis were grown under standard conditions. Growth rate, cell volume, production, and composition (dry weight, carbohydrate, protein, lipid) were measured. Significant differences occurred between strains in all of these attributes (at times 2 to 3 fold), but no clear pattern emerged that one strain was superior. Of note was that for some measurements, strain differences were significantly greater than differences between species. The strains were then fed to rotifers, and a number of parameters were measured: growth rate, reproductive rate, fecundity attributes, a number of developmental rates, and composition (dry weight, carbohydrate, protein, lipid). There were significant effects of prey strain on some of these attributes, but none was dramatic (rarely more than 10% and occasionally up to 30%), suggesting that aquaculturists need not be too concerned regarding which I. galbana strain they use. However, we do indicate subtle differences, induced by different prey strains and suggest that for maximum productivity these differences should be considered.     

In vivo gonadotropic effects of recombinant Japanese eel follicle-stimulating hormone

Recombinant Japanese eel follicle-stimulating hormone (rjeFSH) produced by methylotrophic yeast was subjected to in vivo bioassay to assess its gonadotropic activities and availability to artificially induce maturation of this species. Intramuscular injections of rjeFSH into male eels at doses of 0.1 and 1.0 U/g body weight were repeated 3 times during 12 days. The rjeFSH significantly increased plasma 11-ketotestosterone levels, and induced both testicular growth and spermatogenesis in a dose-dependent manner. These results demonstrate that rjeFSH is effective in promoting male eel gamatogenesis in vivo. Instead of scarce native eel FSH, abundant recombinant eel FSH is now ready for future application to maturation induction of Japanese eel.     

A comparative study of sexual product quality in F1 hybrids of the bream Abramis brama?×?the silver bream Blicca bjoerkna

The gonadosomatic index at spawning, absolute fecundity, and egg size for the female sexual products as well as the density and consistency of semen for the male sexual products were examined in cultured Abramis brama?×?Blicca bjoerkna F1 hybrids and compared with the parental species at their first sexual maturity. Females ovulated under environmental conditions, and their eggs were weighed, counted and measured. Semen of males was macroscopically examined and spermatozoa counted using a hemocytometer. Results revealed that hybridization affected the quality of female and male gametes but with an overlap between hybrids and parents. The gonadosomatic index and fecundity were significantly lower than those of parental species. Egg sizes in hybrids showed a parental effect but to the benefit of hybrids. Semen of hybrids was more diluted which was classified into two groups: the white semen overlapping slightly with parents and the aqueous without any overlap with parents. Overlapped areas between hybrids and parents in term of quality of sexual products could translate that females and males of these hybrids have the biological capacity to produce high quality gametes and thus, a greater chance to produce F2 and backcross generations in rivers.     

中间球海胆与马粪海胆杂交家系早期生长比较和亲本配合力估计

为比较中间球海胆(Strongylocentrotus intermedius)与马粪海胆(Hemicentrotus pulcherrimus)杂交家系间的生长差异,评估杂交家系亲本在体重上的配合力,构建了种间杂交家系共42个。采用动物模型、约束性最大似然法(REML)和最佳线性无偏预测(BLUP)等方法估计了杂交海胆250、295和340日龄体重的育种值,以及各亲本的一般配合力(GCA)和各亲本组合的特殊配合力(SCA)。采用方差分析方法,比较了体重表型值和育种值在杂交家系间的差异。结果表明,3个生长阶段杂交家系间体重的表型值和育种值差异均达到极显著水平(P0.01),体重育种值在家系间的差异大于表型值,在50%家系留种率下,育种值选择和表型值选择的家系相同率介于88.89%~94.44%,育种值选择具有0.93%~4.83%的选择效率优势;250、295和340日龄各父本的一般配合力分别介于–0.22~0.33,–0.31~0.41和–0.29~0.31,各母本的一般配合力分别介于–0.24~0.33,–0.31~0.41和–0.28~0.28,各父母本组合的特殊配合力分别介于–0.07~0.09,–0.10~0.13和–0.32~0.32,M5、M6和M17等父本的一般配合力始终较高,F9、F11和F19等母本的一般配合力始终较高,M5F9和M6F11等杂交组合的特殊配合力始终较高。