Population structure and genetic basis of the agronomic traits of upland cotton in China revealed by a genome‐wide association study using high‐density SNPs

Gossypium hirsutum L. represents the largest source of textile fibre, and China is one of the largest cotton‐producing and cotton‐consuming countries in the world. To investigate the genetic architecture of the agronomic traits of upland cotton in China, a diverse and nationwide population containing 503 G. hirsutum accessions was collected for a genome‐wide association study (GWAS) on 16 agronomic traits. The accessions were planted in four places from 2012 to 2013 for phenotyping. The CottonSNP63K array and a published high‐density map based on this array were used for genotyping. The 503 G. hirsutum accessions were divided into three subpopulations based on 11 975 quantified polymorphic single‐nucleotide polymorphisms (SNPs). By comparing the genetic structure and phenotypic variation among three genetic subpopulations, seven geographic distributions and four breeding periods, we found that geographic distribution and breeding period were not the determinants of genetic structure. In addition, no obvious phenotypic differentiations were found among the three subpopulations, even though they had different genetic backgrounds. A total of 324 SNPs and 160 candidate quantitative trait loci (QTL) regions were identified as significantly associated with the 16 agronomic traits. A network was established for multieffects in QTLs and interassociations among traits. Thirty‐eight associated regions had pleiotropic effects controlling more than one trait. One candidate gene, Gh_D08G2376, was speculated to control the lint percentage (LP). This GWAS is the first report using high‐resolution SNPs in upland cotton in China to comprehensively investigate agronomic traits, and it provides a fundamental resource for cotton genetic research and breeding.     

miR-29b2c重组腺病毒的构建及对胃癌细胞增殖和迁移的影响

构建了miR-29b2c重组腺病毒Ad-miR-29b2c,考察了其对HGC-27、MGC-803胃癌细胞增殖及迁移的抑制作用。采用PCR从基因组扩增miR-29b2c片段,并克隆至腺病毒穿梭载体pAdTrack-CMV中,构建穿梭质粒pAdT-29b2c,经酶切及测序鉴定。穿梭质粒经PmeⅠ线性化后与腺病毒骨架载体共转化BJ5183感受态,产生重组腺病毒质粒Ad-miR-29b2c,再经PacⅠ线性化后转染293A细胞进行包装。重组腺病毒扩增后感染HGC-27细胞,通过MTT及细胞迁移实验观察Ad-miR-29b2c对HGC-27、MGC-803细胞增殖及迁移的影响。采用Western blotting检测Ad-miR-29b2c对HGC-27、MGC-803细胞δ-catenin蛋白表达的影响。酶切、测序及荧光定量PCR结果表明重组腺病毒构建成功,miR-29b及miR-29c在HGC-27细胞过表达。MTT实验表明Ad-miR-29b2c能显著抑制HGC-27、MGC-803细胞增殖。细胞迁移实验表明Ad-miR-29b2c能显著抑制HGC-27、MGC-803细胞迁移。此外,Ad-miR-29b2c能显著降低HGC-27、MGC-803细胞δ-catenin蛋白表达水平。综上所述,构建了miR-29b2c的重组腺病毒,并发现其可以抑制胃癌细胞HGC-27和MGC-803的增殖及迁移,该作用可能与miR-29抑制HGC-27、MGC-803细胞δ-catenin蛋白表达有关。     

金鱼同工酶的发生遗传学研究——Ⅲ.金鱼同工酶基因座位的加倍与多倍性

以鲫鱼和金鱼为材料,用葡萄糖-6-磷酸脱氢酶(G6PD)、乳酸脱氢酶(LDH)和苹果酸脱氢酶(MDH)同工酶体系作为基因标志,从检测同工酶的多重组合形式来研究基因的加倍与演化。对彩鲫与金鱼G6PD和LDH同工酶的分析结果表明,它们均具有与四倍体鱼类相应的谱带。因而说明了金鱼的G6PD和LDH同工酶基因座位的加倍与染色体的多倍性有关,为金鱼是四倍体的假说提供了证据。而对MDH同工酶的分析却得到了与二倍体鱼类相同的谱带数。这可能与加倍基因发生突变而不表达有关。     

浙江古田山自然保护区苔藓植物区系特点及其与邻近山体的比较

浙江开化县古田山自然保护区共有苔藓植物３２５种（包括种下等级）其中苔类植物８９种,隶属于２２科和３９属,藓类植物２３６种,隶属于３３种和１０３属,古田山苔藓植物区系地理成分复杂,以东亚成分为主,欧亚－北美成分和世界热带成分也占有较大的比例;地理联系广泛,与日本苔藓植物区的联系较为密切,古田山苔藓植物区系及邻近几个山体苔藓植物区系的比较结果表明,古田山苔藓植物区系介于安徽黄山和江西三清山之间,并与三     

凡纳滨对虾繁育系统菌群结构及优势菌遗传多样性分析北大核心

【目的】探讨凡纳滨对虾(Litopenaeus vannamei)工厂化繁育系统内发生细菌性玻化症(shrimp postlarva bacterial vitrified syndrome,BVS)时期可培养微生物的菌群特征以及优势病原菌的遗传多样性。【方法】采用细菌体外培养方法结合基因测序技术对不同育苗阶段的亲虾、受精卵、无节幼体、蚤状幼体、糠虾幼体、仔虾,及其育苗池水和饵料内可培养细菌菌群的组成与结构特征进行研究,并通过多位点序列分析(multilocus sequence analysis,MLSA)方法解析病原菌的遗传多样性。【结果】系统内分离纯化的526株具有典型形态差异和群落优势的细菌分属于4门5纲16目24科38属113种。在纲水平上γ-变形菌纲(Gammaproteobacteria)丰度最高,共453株,占总分离株的86.1%;在属水平上弧菌属(Vibrio)丰度最高,共369株,占总分离株的70.2%;在种水平上,溶藻弧菌(Vibrio alginolyticus)为最优势种,共112株,占总分离株的21.3%,并且分布于整个繁育系统,在饵料中具有最高丰度。多元关联分析表明,随着对虾幼体的发育,饵料对幼体体内可培养细菌的菌群结构影响逐渐增加。对112株潜在溶藻弧菌的MLSA分析表明,其中100株菌株进一步确认为溶藻弧菌。进一步利用MLSA构建系统发育树分析其遗传多样性发现,100株溶藻弧菌分为9个簇,分离自同类样品的菌株广泛分布在不同的簇中。【结论】在BVS发生时期,凡纳滨对虾工厂化繁育系统中具有丰富的可培养微生物种类。对虾幼体发育过程中,饵料对幼体体内可培养细菌的菌群结构具有重要影响。溶藻弧菌为凡纳滨对虾工厂化繁育系统中的优势弧菌,分布于整个繁育系统,且具有丰富的遗传多样性。本研究为解析对虾繁育系统可培养微生物演替规律提供了数据支撑,也为对虾苗期病原防控和健康养殖提供了科学依据。