棕色田鼠不同性别中R-spondin1基因的特殊表达

哺乳动物睾丸决定的诱导一般依赖于Sry基因,然而棕色田鼠指名亚种的Sry基因已经丢失,而棕色田鼠指名亚种雌雄个体依然有繁殖能力。我们在研究涉及性别决定的一些基因时,发现R-spondin1与性别决定有关。为了探讨R-spondin1在棕色田鼠中的性别决定中的作用,我们用RT-PCR检测R-spondin1在棕色田鼠性腺中的表达。研究结果表明R-spondin1仅在出生后不久的棕色田鼠指名亚种雌性个体的卵巢中表达,在出生后的棕色田鼠指名亚种雄性个体睾丸中未见其表达,这说明R-spondin1可能在棕色田鼠指名亚种卵巢发育中具有某种角色。     

Sex determination of Microtus mandarinus mandarinus is independent of Sry gene

PCR was performed with primers corresponding to the Sry HMG-box of the mouse and eight Microtus species. Primers for the SALL4 gene and the ZFY/ZFX gene were used as positive controls. None of these sets of primers can amplify any homologous segment of the Sry gene in the genomic DNA of Microtus mandarinus mandarinus, but both can amplify the Sry HMG-box in the male mouse, SALL4 bands, and ZFY/ZFX bands in both male and female M. m. mandarinus and mouse. Southern blotting was also used. We used primers for the mouse Sry HMG-box to amplify the Sry HMG-box of the mouse, Microtus arvalis (Microtus), and Pitymys duodecimcostatus (Microtus). The probes were labeled with digoxigenin using PCR after being sequenced. Southern blots were used to detect the genomic DNA of M. m. mandarinus using alkaline phosphatase detection. The results showed that there was a 3.95-kb-blotting band in positive controls: mouse, Microtus arvalis, and Pitymys duodecimcostatus. However, no homologous sequence of the Sry HMG-box was detected in the genomic DNA of M. m. mandarinus. Therefore, we speculate that the Sry HMG-box of M. m. mandarinus is absent or had a big change; sex determination of M. m. mandarinus is independent of Sry. The sex determination mechanism without Sry of M. m. mandarinus is also discussed.     

棕色田鼠罗伯逊易位的研究（简报）

The type of chromosome No. 1 and chromosome number from 53 individuals of Microtus mandarinus have been studied and compared in three sex types: XY, XX, XO. We found that the first pair of autosomes are very unstable, and there are three types: (1) M, M (With a double metacentric chromosome), (2) M, T, T, (With single metacentric chromosome). (3) T, T, T, T (Without metacentric chromosome). The chromosome number of the same sex individuals changes regularly with the type change of chromosome No. 1, that is, the increase of one chromosome in 2n number is always accompanied by the increase of two T and the decrease of one M, and vice versa. The synaptonemal complexes (SCs) of spermatocyte in pachytene nuclei from the males (2n = 51) were analysed by the electron microscopy. The SCs studies demonstrate that there are 23 fully paired autosomal bivalents, XY-bivalent and an autosomal trivalent. This trivalent is formed by one metacentric and two telocentric elements and characterized by the presence of two short side-arms. Meanwhile, all trivalents are in a cis configuration. The study of G-banding also demonstrates that the No. 1 autosome polymorphism is caused by Robertsonian translocation. Robertsonian fission is the main reason of the polymorphism of chromosome No. 1 and of variation of chromosome number in M. mandarinus.     

Exclusion of Sall 4 as the sex-determining gene in the Mandarin vole Microtus mandarinus mandarinus

In previous studies, we have shown that the Sry HMG-box is absent in Microtus mandarinus mandarinus (M. m. mandarinus), suggesting that sex determination of M. m. mandarinus is independent of the Sry gene. We amplified a 312 bp fragment within exon 2 of the Sall4 gene in the mouse and M. m. mandarinus using polymerase chain reaction (PCR) and detected Sall4 using fluorescence in situ hybridization (FISH) technique. The probes for the Sall4 gene were labeled with digoxigenin using PCR and hybridized to chromosomes and interphase nuclei of the mouse and M. m. mandarinus. Our results suggested that Sall4 exists in the genome of male and female M. m. mandarinus, and the sequence within exon 2 of the gene is the same in the mouse and M. m. mandarinus. The results also showed that Sall4 is localized on chromosome 6 in M. m. mandarinus. As they are the sex chromosomes in M. m. mandarinus, the results excluded the Sall4 gene from being the testis-determining factor in this species. We propose that in M. m. mandarinus, sex determination is controlled by another yet unknown gene on the sex chromosomes.     

棕色田鼠XO雌体的减数分裂

采用诱导卵泡发育、卵母细胞培养、制备减数分裂染色体标本等技术 ,对棕色田鼠两种雌体 (XO、XX)的减数分裂进行了比较研究。研究结果表明 :棕色田鼠XO和XX雌体在表型和内外生殖器结构上无差异 ;在用孕马血清促性腺激素刺激XO雌体和XX雌体后 ,两者卵巢上的有腔卵泡数目相近 ;两者产生的卵母细胞数目、生发泡破裂数目以及第一极体排放数目 ,统计学分析差异都不显著。同时表明XO雌体的减数分裂过程正常 ,能得到卵母细胞中期Ⅱ分裂相。据此我们认为 :雌体 (XO)与雌体 (XX)的卵巢功能都正常 ,两者的卵母细胞均具有较强的成熟能力且无差异。因此 ,棕色田鼠XO个体是核型异常、育性正常的雌体。另外 ,具有三种遗传性别的棕色田鼠可能是处于XX/XY与XO/XY性别决定系统进化途径的中间类型 ,其性别决定系统仍处于变化之中     

棕色田鼠血液生理生化指标的测定

报道了棕色田鼠指名亚种的正常血象值及几项血液生化值。结果表明,各项备注学和血液生化学参数值在成年个体间无性别差异（附红细胞数、血红蛋白浓度、红细胞压积外,但此三项指标尚未达到极显著差异水平）。与其它仓鼠科动物的血液生理生化参数值相比较,棕色田鼠除红细胞数、血红蛋白浓度及中性粒细胞略低外,其它各项参数虽有差异,但均无统计学意义。     

棕色田鼠性别决定研究进展

哺乳动物性别决定方式属于雄性异配型性别决定, 依赖于Y染色体, SRY基因是性别决定中最重要的基因。文章报道了棕色田鼠指名亚种有Y染色体, 但是Y染色体上没有SRY基因, 性别决定不依赖于SRY基因, 排除了R-spondin 1基因是性别决定基因, 同时讨论了棕色田鼠指名亚种SRY基因缺失后可能的性别决定 机制。     

棕色田鼠的发声及其频谱分析

对不同年龄的棕色田鼠在不同状态下的发声进行了声谱分析,以研究其发声与行为之间的关系及其发育规律。棕色田鼠幼体的频谱图较简单,一般有１－２个波峰,主能峰频率在１８００ＨＺ左右,且能量区为１个,位于中频区（１３００－２５００ＨＺ）;发声以单音节为主,持续４０－１００μｓ。亚成体频谱图较幼体复杂,为２个相近的能量区,均位于中频区（７５０－１３２０Ｈｚ,１４３１－１５７０Ｈｚ）,ＭＰＦ＝９４５Ｈｚ;叫声单     

中国遗传学会科普工作会议在京召开

培养温度是花药培养的一个十分重要的条 件。但是有关这方面研究的报道是不多的。特 别是早期的一些报道,不但内容比较简单,而且 试验的温度范围都在28℃ 以下^[7-9.14.16]近年 来甘肃农科院等一些单位开始试验用高温培 养,得到良好的效果^[4.5.10.15不过陈英等在水 稻上初步看到在高温培养下花粉愈伤组织的诱 导率虽然提高,但愈伤组织的分化能力有降低 的趋势,特别是当愈伤组织转分化培养基的时 间偏晚时更是如此^[5]。我们过去在小麦上也见 到过类似现象^[1]。因此近年来我们探索了在高 温下诱导的小麦花粉愈伤组织的分化能力的保 持间题。但在这一研究中又看到不同基因型对 培养温度有不同的反应,从而又就这种对培养 温度反应的基因型差异做了初步的遗传学分 析。本文先报道关于基因型差异方面的结果。 其他结果将另文报道。     

Numerical and structural variations of the X chromosomes and no. 2 autosomes in mandarin vole, Microtus mandarinus (Rodentia)

Here we describe our studies on Microtus mandarinus faeceus of Jiangyan in Jiangsu province of China. By karyotype and G-banding analysis we have found variation in chromosome number and polymorphisms of the X chromosome and the second pair of autosomes of the subspecies. Chromosome number of the subspecies is 2n=47-50. The subspecies has three kinds of chromosomal sex: XX, XO and XY, among which one of the X chromosomes is subtelocentric (X(ST)) and the other is metacentric (X(M)). After comparing karyotypes of different subspecies, we found the specific cytogenetic characteristics of Microtus mandarinus, that is they have three kinds of chromosomal sex: XX, XO and XY; X chromosomes are heteromorphic; the chromosome number of female individuals are one less than male individuals; chromosome number of XX individuals are equal to that of XO ones. We hypothesize that Robertsonian translocation is the main reason of the polymorphism of the second pair of autosomes and variety of chromosome number, and it also causes the chromosome number evolution in different subspecies of Microtus mandarinus.     

Chromosomal polymorphism of mandarin vole,Microtus mandarinus (Rodentia)

The mitotic and meiotic chromosomes of mandarin vole, Microtus mandarinus Milne-Edwards, from Shandong Province of China were analyzed by conventional, G- and C-banding and Silver-staining techniques. We detected chromosomal polymorphism in the vole, exhibiting diploid chromosome numbers 2n = 48-50 and variable morphology of the 1st pair, one medium sized telocentric pair and the X chromosomes. Four types of karyotypes were revealed in the population. According to banding analysis, there were pericentric inversion, Robertsonian fusion and translocation in M. mandarinus karyotype evolution. The X displayed two different morphologies, which could be explained by prericentric inversion and a telocentric autosome translocation.     

棕色田鼠对熟悉和陌生异性尿液的识别

本文通过直接接触和非直接接触尿液的方式,探讨了棕色田鼠尿液中挥发性和非挥发性成分在气味识别中的作用。结果表明:在直接接触的情况下,棕色田鼠对熟悉异性鼠的尿液表现出明显的选择倾向;在非接触情况下这种倾向不明显;雌雄棕色田鼠在非接触情况下共处后,在直接接触尿液时,雌雄鼠都对异性熟悉鼠的尿液表现出明显的选择倾向。通过实验发现:棕色田鼠不但能够在直接接触的情况下识别熟悉和陌生异性鼠尿液,而且能够通过感知个体产生的挥发性化学物质而对陌生的异性个体形成记忆,在以后通过其尿液对其进行识别,而在此过程中尿液中非挥发性成分可能也起着一定作用。     

棕色田鼠小肠肌间神经丛NOS的组织化学观察

用NDP-黄递酶组织化学法研究了NOS在棕色田鼠（Microtus mandarinus)小肠肌间神经丛的分布,同样的方法对大白鼠进行了实验比较。结果发现,棕色田鼠小肠肌间祖辈 经丛NOS阳性神经元形态各异,大小悬殊数倍;在神经节和阳性神经纤维中可见阳性神经元呈“串珠”状和“U”型排列。10倍镜下记数100个视野,观察到阳性神经元平均密度为42.8个/mm^2,每个视野内平均有神经节12.4个,每个神经节内平均有NOS阳性神经元8.5个,占其神经节内神经元总数的27.2%,棕色田鼠为野生草食性动物,其NOS在小肠肌间神经丛的分布与其他杂食性啮齿类有相同之处,但也存在着种属差异。     

Comparison of social interaction and neural activation in the main olfactory bulb and the accessory olfactory bulb between Microtus mandarinus and Microtus fortis

To gain insight into the function of AOB and MOB during different social interaction and in different vole species,the behaviors and neural activation of the olfactory bulbs in social interactions of mandarin voles Microtus mandarinus and reed voles Microtus fortis were compared in the present research.Mandarin voles spent significantly more time attacking and sniffing their opponents and sniffing sawdust than reed voles.During same sex encounters,mandarin voles attacked their opponents for a significantly ...     

棕色田鼠胃肠道5-羟色胺细胞的免疫组织化学定位

应用ABC免疫组织化学方法,对棕色田鼠胃肠道内5-羟色胺细胞进行了免疫组织化学定位和形态学观察.结果 表明:5-HTIR细胞在棕色田鼠胃肠道的各段均有分布,其中以十二指肠和直肠段分布密度最高,胃底、胃幽门部、空肠、回肠、盲肠段其次,胃贲门部、胃体、结肠段分布密度最低.5-羟色胺细胞位于胃腺上皮、肠粘膜上皮、肠腺上皮及固有膜,有圆形、椭圆形、梭形、楔形和不规则形,有的还具有胞突.对棕色田鼠胃肠道5-HTIR细胞的分布、形态与功能相适应的特点进行了讨论.     

The behaviour and structure of the sex chromosomes in spermatocytes of Microtus oeconomus

The meiotic behaviour and structure of the sex chromosomes of Microtus oeconomus (2n=30) in Giemsa stained preparations are described. The X-Y pair appears as a sex vesicle at late zygotene. At late pachytene an unfolded sex vesicle is visible. A condensed sex vesicle appears during pre-diffuse diplotene and starts to unfold again during post-diffuse diplotene. At diakinesis and metaphase I the X and Y chromosomes can be recognized in an end-to-end association. During anaphase I, interkinesis and metaphase II the sex chromosomes are heteropycnotic and can therefore easily be recognized during the final stages of meiosis. During spermiogenesis the X and Y chromosomes can be identified in Giemsa stained preparations until the stage of spermatid elongation.