水稻核不育系6442S—7显性早熟性的遗传分析

研究了早籼核不育系6442S-7与明恢63等16个中迟熟品种杂交F1及其部分组成F2和B1F1的抽穗期遗传.结果表明,6442S-7具有完全显性早熟特性,主要受2对无连锁关系的显性早熟基因控制.同时,还对IR68,献国、9311和BG1639等其他4个迟熟品种与6442S－7杂交F1和F2代,以及三交F1代的抽穗期进行遗传分析,发现IR68、献国和BG1639等4个迟熟品种均含1对等位的不完全显性抑制基因,可部分抑制6442S－7显性早熟基因的表达。认为6442S－7携带的显性早熟基因对水稻遗传改良具有重要的应用价值。     

水稻小穗特征基因FZP的图位克隆

FZP是水稻中控制小穗分化的一个关键基因,先前已将它定位在第7染色体上。通过进一步对该基因进行精细定位和图位克隆,找到2个SSR标记NRM6和NRM8,将该基因锁定在一个遗传距离为1．2cM的范围内(两标记与目标基因的遗传距离分别为0．2cM和1．0cM),相应的物理距离为144kb。发现在预期的目标基因位置,存在一个具有类似AP2结构域的基因。已知AP2是一个控制植物花发育的重要基因。因此,这个基因应是FZP的一个候选基因。PCR扩增结果显示,突变体中该基因有一个大约4kb的插人片段,与向共分离。由此可以初步认为,该基因就是FZP。     

在钙离子敏感性方面与RCH1遗传互作的酿酒酵母基因的筛选

酿酒酵母ScRCH1是白念珠菌CaRCH1的同功基因,作为人体溶质转运蛋白SLC10A7的同源蛋白,两者都是细胞质膜上钙离子内流的抑制因子。为了研究酿酒酵母RCH1与基因组中其他基因之间的遗传互作,利用合成遗传阵列(Synthetic Genetic Array,SGA)方法构建了RCH1分别与其他非必需基因之间的双基因缺失株文库。钙离子表型筛选表明RCH1与17个基因之间存在遗传互作,其中4个基因BUD9、THR1、RAS2和CPR7在钙离子敏感性方面的功能以前没有报道过。这些结果为深入研究Rch1对钙离子稳态的调控提供了参考。     

女孩性早熟患者中检出一种新的雌激素受体基因突变

对收集的16例未见血液雌激素水平升高的临床女孩性早熟患者的外周血样本,利用PCR-SSCP方法筛查了雌激素受体基因编码区的可能突变。结果在1例患者发现：其雌激素受体基因8号外显子编码精氨酸的548位密码子,1个C→T转换导致精氨酸残基被半胱氨酸所替代;这一突变使DNA序列中产生1个BtsⅠ酶切位点,通过PCR-RFLP实验证明此患者为Arg548/Cys548杂合体。为证明该突变在性早熟发生中的作用,构建了一个雌激素受体反应元件报道质粒pGL3-promoter-ERE;成功将野生型ESR1基因定点突变,并克隆于PCR3.1真核表达质粒。报道质粒和表达质粒共转染CMF-7细胞,Cys548突变能够增加萤火虫荧光素酶的产生。结果证明该突变雌激素受体在体外具有高活性特征,因而推测在体内也可能具有相应的过高活性,从而导致女孩的性早熟。     

多耐药肺炎克雷伯菌获得性耐药基因检测及指标聚类分析

目的调查多耐药肺炎克雷伯菌中65种获得性耐药基因和7种可移动遗传元件遗传标记基因的存在状况,以及获得性耐药基因和可移动遗传元件遗传标记基因的相关性。方法收集绍兴地区六家医院分离的肺炎克雷伯菌共20株,采用PCR的方法分析65种β-内酰胺类、氨基糖苷类、喹诺酮类获得性耐药基因和7种转座子、插入序列、接合性质粒遗传标记基因,并用指标聚类分析(SPSS法)分析β-内酰胺类、氨基糖苷类和喹诺酮类获得性耐药基因与整合子、转座子、插入序列、接合性质粒遗传标记基因的相关性。结果 20株肺炎克雷伯菌共检测到14种获得性耐药基因(包括6种β-酰胺类获得性耐药基因、6种氨基糖苷类获得性耐药基因、2种喹诺酮类获得性耐药基因)和6种可移动遗传元件遗传标记基因(包括1种整合子遗传标记基因、3种转座子和插入序列基因遗传标记基因、2种接合性质粒遗传标记基因),其余52种基因均未检测到。SPSS法将上述阳性检出基因分成两大簇群。结论绍兴地区六家医院的多耐药肺炎克雷伯菌菌株对抗菌药物的耐药表型与获得性耐药基因相关,且可移动遗传元件的水平转移使细菌的耐药性在同种细菌菌株之间甚至不同种细菌菌株之间得以快速传播。获得性耐药基因与可移动遗传元件遗传标记基因的指标聚类分析显示:OXA-1、aac(6’)-Ⅰb、qnrB、IMP、aadA5、VEB、KPC、qnrS等基因与接合性质粒遗传标记traA相关,提示这些基因在F接合性质粒上;DHA、aph(3′)-Ⅰ等基因与转座子遗传标记tnpU、tnp513相关,提示它们位于转座子上;TEM-1、aac(3)-Ⅱ、qacE△1与接合性质粒遗传标记trbC相关,提示TEM-1、aac(3)-Ⅱ等基因和Ⅰ类整合子可能位于宽范围接合性质粒上;ant(3″)-Ⅰ、rmtB等基因与ISEcp1较为相关,提示这些基因位于插入序列上。     

人类遗传负荷与近亲结婚

据Mckusick统计,人类单基因病及异常性状已达6457种。染色体畸变综合症和多基因病均在IOO种左右。故人类约有1／5～1／4的人患有某种遗传病或与遗传有关的疾病。这不能不引起人们极大的关注。那么人类的遗传负荷（geneticload）到底有多大？遗传负荷是指一个群体中,由于致死基因或有害基因的存在而使该群体适合度降低的现象。遗传负荷一般用群体中每个个体平均所携带的致死基因或有害基因的数量来衡量。1人类群体遗传负荷的估计方法一个群体的遗传负荷的高低,主要决定于常染体隐性致病基因的频率。而个体患遗传病的威胁,主要来自有害…     

性早熟动物造模研究进展

性早熟是儿童常见内分泌疾病，动物实验在研究性早熟的发病机制和药物治疗中必不可少，因此建立合适的动物模型是研究性早熟的必要前提。啮齿类(如大鼠)与非人灵长类动物的青春期发育过程与人类近似，性腺发育指征明确，是性早熟模型常用动物。根据研究内容不同出现了达那唑、N-甲基-DL-天冬氨酸、雌二醇、高脂饲料、不良生活条件、光照及褪黑素、锰暴露、环境内分泌干扰物、颅脑辐射、脑内药物注射等多种性早熟造模方法。目前多采用阴道开口时间、阴道涂片及动情周期观察、血清性激素水平测定、下丘脑基因检测、性器官检测等多种指标对性早熟动物实验进行评估。     

女孩性早熟患者中检出一种新的雌激素受体基因突变

对收集的16例未见血液雌激素水平升高的临床女孩性早熟患者的外周血样本,利用PCR—SSCP方法筛查了雌激素受体基因编码区的可能突变。结果在1例患者发现：其雌激素受体基因8号外显子编码精氨酸的548位密码子,1个C—T转换导致精氨酸残基被半胱氨酸所替代;这一突变使DNA序列中产生1个BtsⅠ酶切位点,通过PCR—RFLP实验证明此患者为Arg548／Cys548杂合体。为证明该突变在性早熟发生中的作用,构建了一个雌激素受体反应元件报道质粒pGL3-promoter—ERE;成功将野生型ESR1基因定点突变,并克隆于PCR3．1真核表达质粒。报道质粒和表达质粒共转染CMF-7细胞,Cys548突变能够增加萤火虫荧光素酶的产生。结果证明该突变雌激素受体在体外具有高活性特征,因而推测在体内也可能具有相应的过高活性,从而导致女孩的性早熟。     

早花基因在植物教学及遗传育种中的应用

不同植物在开花时间上总是存在一定的差异,这种差异有其本身的遗传基础,也与温度和(或)光周期有密切关系,这些性状可能以数学遗传或质量遗传方式遗传下去。深入研究表明植物均不同程度地存在早花基因,Gottschal和Wellensic报道了豆类中的早花基因,报道认为早花基因是隐性等位基因;Murfet报道了在豆类中的早花基因为一个显性一个隐性组成;Bernard报道了大豆的早花基因为两个隐性等位基因;Coyne和Mattson鉴别出了菜豆的三种开花时间基因;Pinihus报道了春小麦中的一个显性早花基因;Ttai讨论了水稻上的复杂开花基因,其早花基因是由在不同位点上的4     

猪13号染色体上拷贝数变异区内基因信息发掘及遗传规律分析

拷贝数变异(Copy number variation, CNV)是染色体上发生的一种微结构变异, 已引起越来越多研究者的关注。本课题组前期已获得猪13号染色体上的32个CNV区域(CNV region, CNVR), 为了发掘CNVR内的基因信息, 文章在线检索了上述CNVR内的基因并进行基因本体(Gene Ontology)分析。结果共发现236个基因, 其中有注释基因169个, 主要参与蛋白质水解、细胞粘附、大分子降解等生物过程。为了探索这些基因拷贝数变异的遗传规律, 文章选择RCAN1(Regulators of calcineurin 1)基因为候选基因, 利用QPCR方法在莱芜猪群中检测了该基因的拷贝数, 并分析了CNV在莱芜猪3个家系中的遗传规律。结果表明, RCAN1基因在莱芜猪群体中存在拷贝数的缺失、重复现象, 其拷贝数变异的遗传规律符合孟德尔遗传方式。     

Variation in growth form and precocity at birth in eutherian mammals.

Using the flexible Chapman-Richards model for describing the growth curves from birth to adulthood of 69 species of eutherian mammals, we demonstrate that growth form differs among eutherian mammals. Thereby the commonly used Gompertz model can no longer be considered as the general model for describing mammalian growth. Precocial mammals have their peak growth rate earlier in the growth process than altricial mammals. However, the position on the altricial-precocial continuum accounts for most growth-form differences only between mammalian lineages. Within mammalian genera differences in growth form are not related to precocity at birth. This indicates that growth form may have been associated with precocity at birth early in mammalian evolution, when broad patterns of body development radiated. We discuss four non-exclusive interpretations to account for the role of precocity at birth on the observed variation in growth form among mammals. Precocial and altricial mammals could differ according to (i) the distribution of energy output by the mother, (ii) the ability of the young to assimilate the milk yield, (iii) the allocation of energy by the young between competing functions and (iv) the position of birth between conception and attainment of physical maturity.     

Association Between Sexual Precocity and Alleles of KISS-1 and GPR54 Genes in Goats

KISS-1 and GPR54 were regarded as key regulators for the puberty onset and fundamental gatekeepers of sexual maturation in mammals. To explore the possible association between variations in KISS-1 and GPR54 with sexual precocity, mutation screening of exon 1 of KISS-1 and exon 1, exon 3, and partial exon 5 of GPR54 was performed in a sexual precocious breed (Jining Grey goats) and sexual late-maturing breeds (Inner Mongolia Cashmere, Angora, and Boer goats) by PCR-SSCP. The results showed that five novel mutations were identified in exon 1 and partial exon 5 of GPR54 including C96 T, T173C, G176A, G825A, and C981 T. The Jining Grey goats with genotype BB or AB had 1.07 (P < 0.05) or 0.40 (P < 0.05) kids more than those with AA. The Jining Grey goats with genotype DD or CD had 1.80 (P < 0.05) or 0.55 (P < 0.05) kids more than CC, respectively. The present study preliminarily showed an association between alleles B and D of GPR54 with high litter size and sexual precocity in Jining Grey goats.     

Pathogenesis of precocious puberty in hypothalamic hamartoma

Astroglial-derived factors, as transforming growth factor (TGF)alpha and TGFbeta, act in the hypothalamus to activate luteinizing hormone-releasing hormone (LHRH) secretion. Hypothalamic hamartomas (HHs) contain normal nervous tissue in a heterotopic location. When symptomatic, they cause precocious puberty and/or characteristic gelastic seizures. Thus far, the pathogenesis of these alterations remains unknown. By examining two HHs associated with sexual precocity, we found that they contained astroglial cells expressing TGFalpha, but no LHRH neurons. In a third patient with HH, only epilepsy was present, but precocious puberty developed shortly after surgery, probably as a consequence of a surgery-induced lesion. These results imply that some HHs induce sexual precocity by activating endogenous LHRH secretion via astroglial-derived factors.     

Violence, Teenage Pregnancy, and Life History

Guided by principles of life history strategy development, this study tested the hypothesis that sexual precocity and violence are influenced by sensitivities to local environmental conditions. Two models of strategy development were compared: The first is based on indirect perception of ecological cues through family disruption and the second is based on both direct and indirect perception of ecological stressors. Results showed a moderate correlation between rates of violence and sexual precocity (r?=?0.59). Although a model incorporating direct and indirect effects provided a better fit than one based on family mediation alone, significant improvements were made by linking some ecological factors directly to behavior independently of strategy development. The models support the contention that violence and teenage pregnancy are part of an ecologically determined pattern of strategy development and suggest that while the family unit is critical in affecting behavior, individuals’ direct experiences of the environment are also important.     

Clinical implications of the organizational and activational effects of hormones

Debate on the relative contributions of nature and nurture to an individual's gender patterns, sexual orientation and gender identity are reviewed as they appeared to this observer starting from the middle of the last century. Particular attention is given to the organization-activation theory in comparison to what might be called a theory of psychosexual neutrality at birth or rearing consistency theory. The organization-activation theory posits that the nervous system of a developing fetus responds to prenatal androgens so that, at a postnatal time, it will determine how sexual behavior is manifest. How organization-activation was or was not considered among different groups and under which circumstances it is considered is basically understood from the research and comments of different investigators and clinicians. The preponderance of evidence seems to indicate that the theory of organization-activation for the development of sexual behavior is certain for non-human mammals and almost certain for humans. This article also follows up on previous clinical critiques and recommendations and makes some new suggestions.     

Sexual Precocity in A 2-Year-Old Boy Caused by Indirect Exposure to Testosterone Cream

ObjectiveTo report a rare case of sexual precocity caused by inadvertent exposure to testosterone cream.MethodsWe report the clinical, laboratory, and radiologic findings of a boy presenting with sexual precocity; review short- and long-term consequences; and discuss preventative measures.ResultsA₂ and 7/12-year-old boy had onset of pubic hair without testicular enlargement and a period of rapid linear growth. History revealed possible topical testosterone exposure from close contact with the child’s father. On physical examination, the boy had Tanner stage II pubic hair distribution. Laboratory evaluation findings were normal for age except for the testosterone concentration, which was comparable to late-pubertal and adult male levels at 371 ng/dL (reference range, < 3-10 ng/dL for prepubertal male). Brain magnetic resonance imaging and testicular ultrasonography were normal. Skeletal age was advanced at age 4 and 6/12 years. Repeated laboratory evaluation, after the child’s father ceased testosterone use, revealed a normal testosterone concentration of 10 ng/dL. Thus, this boy’s sexual precocity was attributed to inadvertent exogenous androgen exposure.ConclusionsWhen examining a child with sexual precocity, asking about possible exposure to androgens and estrogens is important. Patients being treated with these products should be educated about the possible risks of testosterone exposure to others and ways to limit exposure. (Endocr Pract. 2008;14:1027-1030)     

离乳大鼠假性性早熟模型的建立及对雌活性物质的应答

以雌激素含量明确的避孕药物作诱导剂观察了其对离乳Wistsar大鼠性成熟的影响,结果显示在给予避孕药后体重、乳腺、阴门、阴道上皮细胞、卵巢、子宫均发生类似人体假性性早熟变化,而肾上腺、脑垂体、甲状腺等与对照组比较均未见明显差异。     

Sexual development in early- and late-maturing Bos indicus and Bos indicus x Bos taurus crossbred bulls in Brazil

Two experiments were conducted to evaluate sexual development in early- and late-maturing Nelore (Bos indicus) and Canchim (3/8 Bos indicus x 5/8 Bos taurus crossbred) bulls and to determine predictors of sexual precocity, and pubertal and maturity status. In Experiment 1, 12 Nelore bulls where examined from 300 to 900 days of age. Puberty was characterized by an ejaculate containing > or =50 million sperm with > or =10% motile sperm, and maturity by an ejaculate containing > or =70% morphologically normal sperm. In Experiment 2, 28 Canchim bulls where examined from 295 to 488 days of age and puberty was characterized by an ejaculate containing > or =30% motile sperm. In both experiments, bulls were classified as early- or late-maturing based on age at puberty. Early-maturing bulls were younger (P < 0.05) than late-maturing bulls at puberty (527 days versus 673 days in Experiment 1 and 360 days versus 461 days in Experiment 2) and at maturity (660 days versus 768 days in Experiment 1). In general, early-maturing bulls were heavier and had greater scrotal circumference (SC), testes, and testicular vascular cone diameter than late-maturing bulls during the experimental period. Scrotal circumference adjusted for 365 days of age was a good predictor of sexual precocity; minimum yearling SC of 19 and 24 cm for Nelore and Canchim bulls, respectively, had the best predictive values. Early-maturing bulls were lighter and had smaller SC at puberty than late-maturing bulls; therefore, sexual precocity was not related to the attainment of a threshold body weight or testicular size earlier, but to lower thresholds in early-maturing bulls. When predictors of pubertal status were evaluated, SC had the best sensitivity/specificity relationship in Nelore bulls, and high sensitivity and specificity in Canchim bulls. When predictors of sexual maturity were evaluated in Nelore bulls, age, weight, and SC had similar sensitivity, specificity, and predictive values. At puberty, approximately 60% of the sperm present in the ejaculate were morphologically defective. Changes in semen quality after puberty in Nelore bulls were characterized by increased motility and proportion of morphologically normal sperm, with a decrease in the proportion of major sperm defects. In conclusion, early-maturing bulls were more developed in the pre-pubertal period and attained puberty at earlier stages of body and testicular development than late-maturing bulls. Yearling SC could be used to select bulls for sexual precocity and SC was the best predictor of pubertal status. Age, weight, and SC were equally good predictors of sexual maturity in B. indicus bulls.     

The magnificent compromise: cortical field evolution in mammals

The neocortex of mammals is composed of cortical fields that have a unique organization associated with the animal's ecological niche and lifestyle. Each cortical field has a specific pattern of connections with other cortical fields and brain structures, and together they comprise a neocortical network that generates a variety of behaviors. These networks and the behaviors they generate are variable across mammals, and are particularly complex in some species such as humans. Here I discuss the mechanisms that contribute to neocortical organization in mammals, and how this organization has been altered to generate the variability that exists in different lineages.     

McCune-Albright syndrome in a boy may present with a monolateral macroorchidism as an early and isolated clinical manifestation

BACKGROUND: Testis enlargement in McCune-Albright syndrome (MAS) is generally bilateral and associated with clinical and biochemical manifestations of sexual precocity. CASE REPORT: We describe for the first time an unreported clinical expression of MAS in a 4.6-year-old boy presenting with monolateral testis enlargement and no signs of sexual precocity or other clinical manifestations of MAS at the time of presenting with macroorchidism. Both testosterone and LHRH-stimulated gonadotropin levels were in the prepubertal range. Serum inhibin B was increased to a pubertal level indicating Sertoli cell activation. The histological and immunocytochemical evaluation of the enlarged testis revealed Sertoli cell hyperplasia with no mature Leydig cells. Mutation R201C of GNAS1 gene, classically responsible for MAS, was identified in DNA samples from the right testis biopsy and leukocytes. CONCLUSIONS: (a) MAS should be taken into consideration in the clinicopathological approach to a boy with monolateral macroorchidism; (b) testicular enlargement may be only the presenting clinical manifestation of MAS and is not necessarily linked to manifestations of peripheral precocious puberty; (c) testicular autonomous hyperfunction in MAS may be restricted to Sertoli cells, as also demonstrated previously by others.