北京地区两个封闭群巴马小型猪的群体遗传质量分析

目的对北京地区两个封闭群巴马小型猪群体进行遗传质量评价与分析。方法利用DB11/T828.3-2011中的25对微卫星引物,对A、B两个巴马小型猪群体进行微卫星分型及遗传参数计算。结果 A、B两巴马小型猪群体分别得到126和160个等位基因,平均杂合度分别为0.6541、0.6973,平均多态信息含量(PIC)分别为0.6037、0.6605,两者的遗传距离为0.2650。结论 B群巴马小型猪群体具有较好的遗传多样性和稳定性,符合封闭群动物的群体遗传特征。     

封闭群实验用小型猪遗传标准的建立

目的建立封闭群实验用小型猪遗传质量标准和遗传质量检测方法。方法根据群体遗传学理论。参照实 验动物哺乳类实验动物的遗传质量控制(GB 14923-2001),在查阅大量文献资料的基础上,建立封闭群实验用小型 猪遗传标准。检测方法采用微卫星标记分析技术。从GeneBank中挑选出的100个猪微卫星位点进行PCR扩增和 条件优化,通过琼脂糖电泳、聚丙烯酰胺电泳和STR扫描三级筛选．根据位点在染色体分布情况和等位基因数目、 多态性等优化出适于封闭群实验用小型猪遗传检测的微卫星位点组合,建立检测方法。结果初步建立了封闭群 实验用小型猪遗传质量标准和检测方法。     

STR扫描技术对融水小型猪群体遗传结构的分析*

目的 应用STR扫描技术分析融水小型猪群体的遗传结构。方法 选用北京市地方标准封闭群实验用小型猪的遗传质量监测提供的25个微卫星位点对广东省医学实验动物中心小型猪研究基地F1代30头融水小型猪基因组DNA进行PCR扩增,对扩增产物进行STR扫描,运用popgene32软件对该融水小型猪进行群体遗传结构分析。结果 融水小型猪F1群体平均观测等位基因数为9.4400,平均有效等位基因数为5.2966,平均香隆指数为1.8085,平均有效杂合度为0.7737。结论 STR扫描技术适用于融水小型猪群体遗传结构分析;初步掌握了融水小型猪遗传结构。     

全国首次小型猪实验动物化与开发利用研讨会在北京召开

早在 19世纪 ,科学家就发现猪在解剖、生理和代谢等方面与人类十分接近 ,是极为理想的实验动物 ,因而 ,猪的实验动物化工作一直受到国际科学界的普遍重视。特别是近年来 ,猪作为人类器官移植的供体研究成为学术界关注的焦点。但由于实验动物化的工作一直未能突破近交系的瓶颈 ,致使相关领域的研究受阻。我国小型猪资源得天独厚 ,早在七十年代 ,我国科学工作者就开始了小型猪近交系的选育工作 ,科学工作者对小型猪资源的开发利用研究也给予了高度重视。目前 ,云南的西双版纳小耳猪、中国农业科学院培育的五指山小型猪、广西的广西巴马小型猪…     

中国小型猪实验动物化培育及种质特异性研究

1　小型猪品系繁多 ,各具特色我国地形、生态条件多样 ,经历代人工和自然选择 ,使我国小型猪品种具有得天独厚的资源和条件。主要的品种有 :海南五指山小型猪 (WZSP)、云南小耳猪、贵州香猪、广西巴马香猪、甘肃合作猪、青海藏猪等。五指山小型猪具有体型小、性成熟早、遗传稳定、可近亲繁殖的特点 ;云南小耳猪具有体型较小、性成熟早、体为黑色等特点 ,通过近亲繁殖 ,已获得近交 2 0代仔猪 ,已分化为体重大小、毛色、体态不一的 8个家系 ;香猪、巴马香猪具有性成熟早、遗传比较稳定、产仔率较高、体毛分别为黑色和白色占 90 %左右等特征…     

广西巴马小型猪生长素(Ghrelin)cDNA的克隆及序列分析

目的扩增广西巴马小型猪生长素(Ghrelin)cDNA序列,分析其序列结构特点,为进一步从分子水平上对广西巴马小型猪的生长发育提供理论依据,也为日后构建原核表达载体、研究Ghrelin基因的生物功能奠定基础。方法以广西巴马小型猪胃底组织总RNA为模板,用特异性引物扩增Ghrelin的cDNA,纯化连接pMD18-T载体后转化大肠杆菌DH5α,筛选阳性克隆体,鉴定后测序。结果经测序证实克隆得到的广西巴马小型猪Ghrelin cDNA序列全长为357 bp,与相关文献报道一致。同源性比较发现,广西巴马小型猪Ghrelin cDNA基因序列与GenBank报道的猪相应序列同源性为99.7%,只有一处发生碱基突变。结论本实验成功克隆了广西巴马小型猪Ghrelin cDNA。     

广西巴马小型猪促生长激素释放激素成熟肽的克隆及序列分析

目的扩增广西巴马小型猪促生长激素释放激素(GHRH),分析其序列结构特点。方法以广西巴马小型猪基因组DNA为模板,用特异性引物扩增GHRH外显子3,再用引物延伸悬挂PCR法扩增GHRH成熟肽,纯化后,连接、转化到大肠杆菌,筛选阳性克隆,测序。结果经测序证实广西巴马小型猪GHRH外显子3及其成熟肽的基因序列与相关文献报道一致。克隆得到的广西巴马小型猪GHRH序列全长为132 bp,其中外显子3基因序列长105bp。同源性比较发现,广西巴马小型猪GHRH外显子3基因序列与GenBank(NCBI)中报到的猪GHRH外显子3相比,同源性为97.14%,有3处发生碱基变化。结论本实验成功克隆了广西巴马小型猪GHRH成熟肽序列。     

三个品系实验用小型猪部分血液生化指标比较

目的检测广西巴马小型猪、五指山小型猪和中国农大小型猪三个品系实验用小型猪的血液生化指标并进行比较。方法选用4月龄广西巴马小型猪和中国农大小型猪,5月龄五指山小型猪,用日立-7600型自动生化分析仪检测三个品系小型猪的血液生化指标,对同一品系雌、雄小型猪的测定值及对3个品系小型猪的13项指标进行组间比较。结果三个品系小型猪的血液生化测定值比较接近。在13项检测指标中,广西巴马小型猪的ALT、BUN低于其他两个品系(P<0.05),五指山小型猪的TG高于而ALP低于其他两个品系(P<0.01)。雌雄小型猪之间除广西巴马小型猪的BUN差异有显著性(P<0.05)外,其余各项指标雌雄间差异不显著(P>0.05)。结论同一品系小型猪的大部分血液生化测定值不受性别影响;3个品系小型猪的血液生化测定值接近。     

固力本钙离子在广西巴马小型猪中注射效果初探

目的以广西巴马小型猪作为实验动物,探讨固力本钙离子用于静脉注射、肌肉注射和皮下注射的可行性。方法去甲肾上腺素静脉滴注巴马小型猪12次(用量2.0 mg/kg体重);固力本钙离子静脉滴注巴马小型猪和用过去甲肾上腺素的实验猪(1粒钙离子的稀释液分别为100 mL~200 mL的生理盐水、葡萄糖水和蒸馏水);固力本钙离子肌肉注射、皮下注射巴马小型猪(1粒钙离子的稀释液分别为100 mL~200 mL的生理盐水、葡萄糖水和蒸馏水);对照巴马小型猪静脉滴注生理盐水50 mL。结果钙离子静注过程中实验猪大多会表现心率、呼吸减缓,实验猪无异常反应,表现安静;钙离子静注稀释液用蒸馏水较好;以2.3 mg/mL的浓度滴注较合适。静注去甲肾上腺素过程中实验猪心率、呼吸加快,反应激烈;经去甲肾上腺素静注后的巴马小型猪对钙离子静脉注射的反应则完全不同,表现安静。钙离子肌肉注射和皮下注射实验猪均无不良反应。结论通过对巴马小型猪的实验,初步确认固力本钙离子可用于静脉注射、肌肉注射和皮下注射。     

AMS／5近交系小鼠培育及其生物学特性的研究

近交纯系动物具有一致的基因型和遣传特征，个体之间差异极小，实验中容易取得一致的结果＾「１．２」。随着医学科学研究的飞速发展，近交系动物的培育及应用愈来愈被人们所重视，为适应不同课题研究需要而培育的近交系动物的品系越来越多。由于各种原因，国内开展这项工作较晚，长期以来我们缺少更多合格的近交动物品系来进行大量生产和供应。我院于１９７４年３月从封闭群ＬＡＣＡ小鼠中选留亲本，进行严格的近亲同胞兄妹交配，宗     

马尾松育种进程中的遗传增益与遗传多样性变化

【目的】通过对广西马尾松3次改良过程中的遗传多样性及改良增益进行分析,总结育种进程中的遗传多样性变化动态。分析通过育种群体结构设计、选择方法提高改良效果的可行性,为制定马尾松长期育种策略及良种发展战略提供理论参考。【方法】以广西马尾松天然群体及第1代、第1.5代、第2代育种群体为材料,采用SSR标记分析其遗传多样性,根据遗传测定结果估算历次改良所得遗传增益。【结果】广西马尾松的第1次改良过程,获得约32%材积增益,损失约14%的低频等位基因,Shannon多样性指数(I)没有发生变化,观测杂合度(H_o)约上升27%。第2次改良过程获得19.34%的遗传增益,损失了约16%的低频等位基因,Shannon指数(I)约下降了6%,观测杂合度(H_o)没有变化,近交系数约下降了20%。第3次遗传改良过程获得23.68%的遗传增益,损失约12%的低频等位基因,Shannon指数(I)下降约25%,观测杂合度(H_o)下降约20%,近交系数下降约47%。【结论】广西马尾松 3次改良均获得了较高的遗传增益,并有效降低了群体的近交程度,遗传多样性损失相对较少。由此说明,所用的选择策略可以有效兼顾遗传增益与遗传多样性。     

林木改良中育种群的概念应用和发展

育种群是组成整个育种群体的多个亚群体,其意义相当于农作物育种的近交系。在美国的一些林木育种项目中,育种群已用来控制种子园的近交、捕获最大的遗传增益的有效措施。育种群的建立不会改变各群内的育种值,但每个育种群内的遗传变异会随近交系数的增加而增加,这为我们在群内选优提供了更大的选择余地。此外,建立育种群只增加一些档案记录工作,并不增加野外工作量。     

Female sticklebacks count alleles in a strategy of sexual selection explaining MHC polymorphism.

The origin and maintenance of polymorphism in major histocompatibility complex (MHC) genes in natural populations is still unresolved. Sexual selection, frequency-dependent selection by parasites and pathogens, and heterozygote advantage have been suggested to explain the maintenance of high allele diversity at MHC genes. Here we argue that there are two (non-exclusive) strategies for MHC-related sexual selection, representing solutions to two different problems: inbreeding avoidance and parasite resistance. In species prone to inadvertent inbreeding, partners should prefer dissimilar MHC genotypes to similar ones. But if the goal is to maximize the resistance of offspring towards potential infections, the choosing sex should prefer mates with a higher diversity of MHC alleles. This latter strategy should apply when there are several MHC loci, as is the case in most vertebrates. We tested the relative importance of an 'allele counting' strategy compared to a disassortative mating strategy using wild-caught three-spined sticklebacks (Gasterosteus aculeatus) from an interconnected system of lakes. Here we show that gravid female fish preferred the odour of males with a large number of MHC class-IIB alleles to that of males with fewer alleles. Females did not prefer male genotypes dissimilar to their own.     

Captivity masks inbreeding effects on male mating success in butterflies

Small isolated populations are frequently genetically less diverse than core populations, resulting in higher homozygosity that can hamper their long-term survival. The decrease in fitness of organisms owing to matings between relatives is well known from captive and laboratory animals. Such inbreeding can have strongly deleterious effects on life-history traits and survival, and can be critical to the success of population conservation. Because pedigrees are hard to follow in the wild, most field studies have used marker loci to establish that fitness declines with increasing homozygosity. Very few have experimentally explored the effects of inbreeding in the wild, or compared observations in the laboratory with field conditions. Here, using a technique involving the transfer of marker dusts during copulation, we show that a small decrease in mating success of captive inbred male butterflies in cages is greatly accentuated in conditions with unconstrained flight. Our results have important implications for conservation and for studies of sexual selection because they show that the behaviours underlying patterns of mating can be profoundly influenced by a history of inbreeding or by any restraining experimental conditions.     

Mate fidelity and intra-lineage polygyny in greater horseshoe bats

Mating strategies that lead to increased kinship within socially cooperative groups may offer inclusive fitness benefits to individuals, but can also result in higher levels of inbreeding. Here we show in a sexually segregated bat species that females avoid this conflict through two mating behaviours. First, most females revisit and breed with specific, individual males across years, so that their single offspring born in different years are full siblings. Second, relatives in the maternal line, including mothers and daughters, share breeding partners (intra-lineage polygyny) more often than expected by chance. Although these behaviours increased levels of co-ancestry among colony members, there was no concomitant rise in inbreeding. We suggest that when females engage in mate fidelity and intra-lineage polygyny, kin ties among female roost mates will be strengthened, thereby potentially contributing to social group cohesiveness. Our findings reveal the hidden complexity that can underlie polygynous breeding, and highlight a new potential route by which female mate choice could influence social evolution.     

The cost of inbreeding in Arabidopsis

Population geneticists have long sought to estimate the distribution of selection intensities among genes of diverse function across the genome. Only recently have DNA sequencing and analytical techniques converged to make this possible. Important advances have come from comparing genetic variation within species (polymorphism) with fixed differences between species (divergence). These approaches have been used to examine individual genes for evidence of selection. Here we use the fact that the time since species divergence allows combination of data across genes. In a comparison of amino-acid replacements among species of the mustard weed Arabidopsis with those among species of the fruitfly Drosophila, we find evidence for predominantly beneficial gene substitutions in Drosophila but predominantly detrimental substitutions in Arabidopsis. We attribute this difference to the Arabidopsis mating system of partial self-fertilization, which corroborates a prediction of population genetics theory that species with a high frequency of inbreeding are less efficient in eliminating deleterious mutations owing to their reduced effective population size.     

近交系BALB／c小鼠繁殖与保种方法的建立和应用

在保种繁殖过程中，采用修饰平行线系统保种法对近交系ＢＡＬＢ／ｃ小鼠进行严格兄妹交配繁殖，保持完整的谱系记录，控制饲养环境条件，成功地建立了ＢＡＬＢ／ｃ小鼠基础群及血缘扩大群，广泛提供科学研究试验应用。     

Effects of a change in the level of inbreeding on the genetic load

"The effects of inbreeding may not be as noticeable in the first generation as the invigoration immediately apparent after crossing". This statement, published in 1919, has received little attention, and has apparently never been tested empirically, although the reduction of the genetic load of populations by inbreeding is well known in theoretical terms. Because inbreeding increases homozygosity, and hence the effectiveness of selection against recessive or partially recessive detrimental alleles, changes in levels of inbreeding can lead to a reduction in the frequencies of such mutant alleles. This results in equilibration at higher population mean fitness and is referred to as 'purging' populations of their genetic load. Severe inbreeding can also reduce genetic load due to overdominant alleles, provided selection coefficients are not symmetrical at all loci, because alleles giving lower fitness will be reduced in frequency at equilibrium. With either fitness model, however, reduction in genetic load takes time, and the initial effect of an increase in inbreeding is reduced fitness due to homozygosity. There are few data relating to the extent to which fitness is reduced during inbreeding in a set of lines and to how long the reduction lasts before increasing again to the initial level, or higher. Inbreeding experiments involving sib mating in mice and Drosophila subobscura, and successive bottlenecks in house flies have yielded some evidence consistent with the purging hypothesis. Here, we report results of an experiment demonstrating a prolonged time-course of recovery of mean fitness under self-fertilization of a naturally outcrossing plant, and also compare our results with expectations derived by computer calculations. Our results show that the genetic load present in an outcrossing population can be explained only with a high mutation rate to partially recessive deleterious alleles, and that inbreeding purges the population of mutant alleles.     

Hartley 豚鼠生物净化群体建立及微卫星遗传质量分析

摘要:目的 对现有 Hartley 豚鼠种群进行剖腹产净化,通过遗传检测,确认净化后的种群符合封闭群遗传特征。方法 生产群中不同繁殖单元广泛选择雌、雄个体,按 1 ∶ 1 比例合笼交配,于合笼后 70 d 实施剖腹产手术,仔鼠人工乳饲喂。 用循环交配法繁殖一代,从 F1 代中选取 30 个个体采集耳部组织样本,提取 DNA,应用 18 个豚鼠基因组微卫星位点进行 遗 传 检 测。 结 果 剖 腹 产 共 获 得 85 只 仔 鼠,成 活 56 只,离 乳 47 只 ( 23 雄、24 雌) ,成 活 率65. 9% ,离乳率 83. 9 % ;18 个豚鼠微卫星位点共检测到 81 个等位基因,平均杂合度 0. 5747,平均多态信息含量( PIC)0. 5216。 Hardy-Weinberg 遗传平衡检测,14 个位点符合 H-W 遗传平衡,3 个位点显著偏离 H-W 遗传平衡,1个位点呈现纯合状态。 结论 通过剖腹产对豚鼠种群进行了净化,净化后的群体具备较理想杂合度,属高度多态性群体,符合封闭群实验动物遗传特征。     

2017—2019 年 CD ( SD)大鼠 240 个 SNP 位点遗传检测结果分析

摘要:目的 2017—2019 年北京维通利华实验动物技术有限公司(以下简称,维通利华) 连续三年参与美国 CharlesRiver Laboratories( CRL)对全球各地设施 CD( SD)大鼠生产群的遗传检测,以评估种群的遗传稳定性、杂交系数及各设施间种群的差异。 方法 从大鼠耳部样品中提取 DNA,使用荧光标记法检测 240 个单核苷酸多态性( SNP ) 基因位点,通过 GenA1Ex6. 5 软件统计分析得到位点多态性( P) 、观测杂合度( Ho ) 、期望杂合度( HE ) 、近交系数( F)和遗传分化系数( FST )等。 结果 位点多态性比例分别为 73. 6% ,76. 9% 和 74. 2% ,遗传具有多样性且保持稳定;杂交系数分别为-0. 02、-0. 06 和-0. 07,符合随机交配特性;遗传分化系数( FST ) 在 0. 05 上下波动。 结论 维通利华的 CD( SD)大鼠种群保持稳定的遗传多样性,符合随机交配方式繁殖,与 CRL 美国基础种群呈低至中等程度的遗传分化,定期的引种措施为保持种群的杂交性和稳定性发挥重要作用。