圆果种黄麻单染色体显微分离与扩增

以圆果种黄麻(Corchorus capsularis L.)品种高雄青皮为研究材料,利用玻璃针显微分离的方法成功分离出高雄青皮的单染色体2条。对获得的单染色体采用LAM-PCR方法进行扩增,电泳结果显示:DNA片段的长度在250～3 000 bp之间。利用Southern blot杂交对扩增产物进行验证,结果表明:获得的扩增片段确实来自高雄青皮的基因组。     

象草和巨菌草的核型分析

为巨菌草的种质鉴定、遗传育种和亲缘关系提供一定的细胞学基础,采用传统压片法,对象草(Pennisetum purpureum schumach)和巨菌草〔Pennisetum giganteum z.x.lin(暂定名)〕的染色体数目及核型进行分析。结果表明:象草和巨菌草的染色体形态较为一致,大部分由中部(m)和近中部(sm)着丝粒的染色体组成,象草和巨菌草的核型公式分别为2n=4x=28=20m+8sm和2n=4x=28=16m+8sm+4st;染色体相对长度组成分别为2n=4x=28=6L+6M2+10M1+6S和2n=4x=28=4L+8M2+10 M1+6S,染色体基数和总数目一致,核型分类均为2A型,不对称系数为58%~60%,均属于较原始的类型。结论:象草和巨菌草的的染色体无明显差异性,从细胞染色体水平上认为两者亲缘关系较近。     

Chromosome Mapping,Expression and Polymorphism Analysis of CRABP1 Gene in Pigs

Cellular retinoic acid-binding protein 1 (CRABP1) is a well-conserved member of cytosolic lipid-binding protein family. It is an important modulator of retinoic acid signaling. Long serial analysis of gene expression (LongSAGE) analysis suggested that CRABP1 gene was differentially expressed during prenatal skeletal muscle development in porcine. Here, we obtained the full-length coding region sequence and genomic sequence of the porcine CRABP1 gene and analyzed its genomic structures. Subsequently, we examined CRABP1 chromosome assignment using INRA-University of Minnesota 7 000 porcine radiation hybrid panel (IMpRH) and explored its tissue distribution in adult Tongcheng pigs and dynamical expression profiles in prenatal skeletal muscle (33, 65 and 90 days post coitus, dpc) from Landrace (lean-type) (described as L33, L65 and L90) and Tongcheng pigs (obese-type) (described as T33, T65 and T90). The CRABP1 gene was mapped to chromosome 7q11-q23 and closely linked to the microsatellite marker SWR1928. Quantitative real-time PCR showed that CRABP1 mRNA was highly expressed in lung and stomach, moderately expressed in placenta and uterus, and weakly expressed in other tissues. Moreover, CRABP1 gene was down-regulated during prenatal skeletal muscle development in both Landrace and Tongcheng pigs and it was expressed much higher in T33 than L33. Two single-nucleotide polymorphisms (SNPs) were detected by sequencing and mass spectrometry methods, allele frequency analysis indicated that g. 281 (G>A) and g. 2992 (G>A) were deviated from Hardy-Weinberg equilibrium in the Landrace and DLY (Duroc×(Landrace×Yorkshire)) pig breeds.     

Production and characterization of Raphanus sativus-Brassica rapa monosomic chromosome addition lines

Breeding of Raphanus sativus‐Brassica rapa monosomic chromosome addition lines (MALs, 2n = 19) was carried out by backcrossing the synthesized amphidiploid line, Raphanobrassica (R. sativus×B. rapa, 2n = 38, RRAA, line RA89) with R. sativus cv. ‘Shogoin’ (2n = 18, RR). In the first cross of Raphanobrassica× radish, four sesquidiploidal BC₁ plants (2n = 28, RRA, RA89‐36‐1, RA89‐31‐1, RA89‐31‐2, RA89‐31‐3) were successfully developed. In these plants, the chromosome configurations of 9II + 10I and 10II + 8I were observed frequently at first metaphase (MI) of meiosis in pollen mother cells (PMCs). The RA 89‐36‐1 plant produced many seeds in the reciprocal backcrosses with radish. About 50% of the BC₂ plants obtained from the cross of RA89‐36‐1 plant × radish were 2n = 19 plants, followed by 2n = 18 plants (24%) and 2n = 20 plants (19%). In the reciprocal cross, 2n = 19 plants were also developed at the rate of 40%. From analysis of specific morphological traits, 2n = 19 plants were classified into eight types (a‐h). When 25 selected primers were used in polyacrylamide gel electrophoresis, random amplified polymorphic DNA (RAPD) markers derived from B. rapa for each type of MAL were detected in numbers between three for e‐type and 16 for b‐type. RAPD markers specific for each type alone were from one (OPE 05‐344) for h‐type to nine for b‐type. In the g‐type, no marker specific to this type alone was observed. However, 19 bands were common between at least two types. These MAL plants exhibited predominantly the chromosome configuration of 9II + 1I at MI of PMCs, pollen and seed fertility being the same level as the radish cv. ‘Shogoin’. From the morphological traits and DNA markers, eight different MAL types among 10 expected were identified.     

长春花碱在牛体外受精胚中染色体标本处理及性别分析

长春花碱是一种常用的细胞分裂阻止剂,在细胞遗传学分析及体外受精胚的性别鉴定等方面有着重要意义.该研究对牛体外受精胚的第一卵裂期染色体标本制作及性比进行了分析.废弃牛卵巢内卵子经体外成熟培养,体外受精20h后,在培养基中添加100ng/ml长春花碱处理8h或10h.结果表明,用长春花碱处理8h的胚胎标本大部分含有可分析的中期分裂像并可进行性别判断,明显高于10h处理的胚胎标本(P<0.05).性比分析表明,牛体外受精的胚胎的雄性发生率略高于雌性发生率.     

利用染色体片段置换系定位水稻粒型QTL

水稻粒型是衡量稻米外观品质的重要指标之一,鉴定和定位水稻粒型QTL对开展水稻粒型分子育种具有重要意义.本研究以8个染色体片段置换系为材料,选用分布水稻12条染色体上的153个SSR标记检测染色体片段置换系的置换片段,采用代换作图法对控制水稻粒型的3个主效QTL进行定位.结果表明:153个SSR标记中有104个标记在亲本间具有多态性,多态率为68.0%;8个染色体片段置换系在第3和第5染色体分别有6个和2个置换片段,置换片段长度分别为14.8 cM、16.6 cM、 15.5 cM、18.9 cM、29.1 cM、35.0 cM、17.9 cM 和17.0 cM,平均长度为20.6 cM;8个置换片段上共鉴定出3个粒型QTL,控制粒长的qGL-3-1 和qGL-3-2分别被界定在水稻第3染色体RM5551与RM6832及RM6832与RM3513之间,遗传距离分别为14.8 cM和5.3 cM的范围内,控制粒宽的qGW-5被界定在水稻第5染色体RM267与RM169之间遗传距离约11.7 cM的范围内.利用染色体片段置换系能准确地定位水稻粒型QTL,qGL-3-1、qGL-3-2和qGW-5的鉴定和初步定位为其进一步精细定位及分子标记辅助选择奠定了基础.     

赖草联会消失突变体的细胞遗传学研究

对赖草（Ａｎｅｕｒｏｌｅｐｉｄｉｕｍｄａｓｙｓｔａｃｈｙｓ）自发联会消失突变体的研究结果表明：突变体在偶线期、终变期尚能正常配对．但从终变期开始，大部分“×”、“Ｖ”、“‖”状二价体提早解离成单价体，从而导致以后各时期持续紊乱。和正常株不同，突变体出现了一定频率的“中—后”期分裂相。这是联会消失突变体的减数分裂特征。突变体的减数分裂过程中出现更多的染色体结构变异，这说明联会消失突变和结构变异有相关的遗传背景。由于减数分裂行为十分紊乱而导致突变体的配子育性和结实率大大下降。     

藜麦品系的染色体数目及核型分析

为探明西藏目前主推藜麦的染色体数目及核型,以西藏农牧学院植物科学学院提供的藜麦品系W4为材料,对其进行根尖染色体常规压片法制片,比较采用8-羟基喹啉、秋水仙素和冰冻方法的预处理时间、1mol/L HCl酸解时间对藜麦染色体制片的影响,探讨最优的根尖处理方法并进行核型分析.结果显示:用0.1%秋水仙素溶液(离体)处理3h,1mol/L HCl 60℃酸解13～14 min的总体作用效果最佳;藜麦W4的核型公式为2n=36=32 m(2SAT)+4sm,核型不对称系数为57.87%,核型分类中属2B型.     

新疆野苹果的不同种下类型染色体核型分析

【目的】新疆野苹果（Malus sieversii）是新疆伊犁地区的主要野生苹果种质资源,是中国苹果资源中的独特分支,加强该资源的研究对保护苹果种质资源的丰富性具有重大意义。对新疆野苹果的不同种下类型进行细胞学分类,探讨新疆野生苹果种下类型之间的亲缘关系,为新疆野苹果资源的保护、开发与利用提供科学依据。【方法】以采自伊犁的新疆野苹果24个种下类型为研究对象,在4月初至4月中旬,选取其幼嫩的茎尖,采用改进的适合新疆野苹果核型分析的染色体制片方法进行压片,并根据不同种下类型染色体数目及其相对长度、平均臂比等核型指标,观察分析新疆野苹果24个种下类型染色体的核型特征。【结果】（1）新疆野苹果24个种下类型均为二倍体,染色体数目为34条,所有种质染色体相对长度平均值为3.23 μm,属小染色体。从着丝点位置观察,多数类型均含有不同数量的m和sm染色体,个别类型只有m染色体,核型公式为2n=2x=34=34m、2n=2x=34=30m+4sm、2n=2x=34=28m+6sm、2n=2x=34=32m+2sm等4种类型。从染色体长度观察,除了香酸野苹果和长柄红霞果以外,其他的类型均含有不同数目的长染色体（L）、中长染色体（M2）、中短染色体（M1）以及短染色体（s）等4种类型,没有发现随体。（2）染色体结构特征方面,新疆野苹果24个种下类型染色体的平均臂比为1.27-1.56,核型不对称系数为56.01%-63.39%。核型类型大部分为1A和1B型,也有个别的2A和2B;1A、1B、2A、2B所占的比例分别为41.67%、37.5%、8.33%和12.50%。（3）进化趋势图显示,黄圆野苹果最为特殊,其核型不对称系数最高（63.39%）,其进化程度最高,其次是霍城圆果野苹果和清香野苹果,小花野苹果的进化程度最低（56.01%）;其余20个种下类型进化趋势具有较高的一致性,趋势较为集中;其中,大扁心野苹果的进化程度最低。（4）聚类分析显示,24个种下类型分为3类,第一类包括9个种下类型,它们具有较高的核型特征相似性,大多数类型的平均臂比大于其他类型,结合进化趋势结果,发现它们的进化趋势比别的类群较高;第二类包括11个,核型类型大多数为1B、2A、2B;第三类4个类型,它们的平均臂比和核型不对称系数最小,核型类型属于1A和1B,说明这类群的遗传相对稳定。【结论】新疆野苹果24个种下类型的核型特征有一定差异,根据核型特征,可以对其进行分类;与传统分类方法比较,其揭示的种下类型之间的亲缘关系更加明晰,聚类结果更能反映出类型之间的一致性与差异性。结合核型特征可初步判断种下类型的进化趋势,这对进一步研究新疆野苹果种下类型的系统进化有重要参考作用。     

Chromosome number in germplasm accessions of Paspalum (Plicatula group) from different regions in Brazil

We determined the chromosome number of 52 accessions of Paspalum from the germplasm collection of the Centro de Pesquisa de Pecuária do Sudeste (CPPSE/EMBRAPA) originating from different regions in Brazil. All accessions belonged to the Plicatula group, 13 of them being P. plicatulum, three P. guenoarum, two P. yaguaronense, two P. compressifolium, one P. atratum, and 31 still unidentified Paspalum sp. Except for a P. yaguaronense accession that presented 2n=60, all the remaining ones presented 2n=40 chromosomes. This is the first report of the chromosome number of P. atratum. Considering that the basic number for most species in the genus Paspalum is ×=10, the accessions analyzed are tetraploids (2n=4×=40) and hexaploids (2n=6×=60). This revised version was published online in July 2006 with corrections to the Cover Date.