Parentage analysis of multi-male social groups of tasmanian native hens (Tribonyx mortierii): genetic evidence for monogamy and polyandry

Accurate estimates of male reproductive success are essential to understanding the evolution of polyandrous mating systems. Here, we use multilocus DNA fingerpinting to assess parentage in an island population of Tasmanian native hens (Tribonyx mortierii), which often live in multi-male and/or multi-female social groups. This isolated population presented special challenges to this technique because it was artificially founded from a small number of individuals in the recent past. DNA profiles from four multilocus minisatellite probes were analyzed for adults and offspring from six social groups using two methods: (1) significance of band-sharing coefficients and (2) distribution among a group's offspring of fragments unique to certain adults. Traditional band-sharing analyses did not provide sufficient resolution to establish parentage in this population due to the high level of band-sharing between adults within groups. In contrast, the distribution of unique fragments suggests that in most cases, all offspring within a group have the same male and female genetic parents, so that monogamy may be the predominant genetic mating system of this species. This forces a rexamination of the evolutionary basis of polyandry in these birds. It also demonstrates some of the difficulties in using these highly polymorphic genetic markers for parentage analyses when putative parents are closely related.     

^32P后标记法测DNA加合物

＾３２Ｐ后标记方法测ＤＮＡ－致癌物的加合物过程是用小球菌核酸酶和脾核酸酶将ＤＮＡ及加合物酶解成２′－脱氧核苷３′－单磷酸（３′－ｄＮｍＰ＋３′－ｄｘｍＰ）,以它为底物,用Ｔ４多核苷酸激酶催化,使γ＾３２ＰＡＴＰ的放射＾３２Ｐ转移反应到底物上,形成２′－脱氧核苷３′５′．ｄＮＤＰ＋３′５′＊ｄｘＤＰ）,用ＯＤＳ－ＴＬＣ和ＰＥＩ－ＴＬＣ结合将标记过的二磷酸分离分辨,用自显影制成加合物的指纹图,液闪计数     

中国林蛙Rana chensinensis遗传多样性初步研究

用寡聚核苷酸探针ＬＺＦ－１，对中国林蛙的基因指纹进行了研究，结果表明，中国林蛙３个居群扔Ｈｉｎｆ－１酶切片段的ＤＮＡ指纹图呈现在个体水平，群居水平和物种水平的高度多态性。     

Prenatal diagnosis of citrullinaemia: Review of a 10-year experience including recent use of DNA analysis

Prenatal diagnosis of citrullinaemia has been accomplished by three different methods to date: (1) enzyme assay of cultured fetal cells; (2) quantification of citrullirie in amniotic fluid supernatant; and (3) incorporation of [¹⁴C]citrulline into protein by cultured fetal cells. Our laboratory has used these methods to perform prenatal diagnosis for 28 fetuses over a 10-year period. More recently, DNA polymorphisms were used for prenatal diagnosis by linkage analysis. Of the 28 fetuses studied, 23 were predicted to be unaffected, four were predicted to be affected, and results were conflicting in one case where [¹⁴C]citrulline incorporation erroneously indicated an affected fetus but linkage analysis correctly predicted an unaffected fetus. Because of low levels of enzyme activity in heterozygotes and in certain amniotic fluid cell types, biochemical diagnosis of citrullinaemia is complicated by the risk of false affected results, although [¹⁴C]citrulline incorporation is relatively reliable. When informative, linkage analysis is the preferable method for cases with a 25 per cent risk. The risk of false affected results makes prenatal diagnosis for cases with less than 25 per cent risk of questionable value.     

现代分子生物技术在废水菌群监测中的应用

荧光原位杂交、DNA指纹等现代分子生物技术在废水治理过程中得到了广泛的应用。对现代分子技术的分类及其在废水菌群监测中的应用进行了简要的论述,并通过各类技术间的比较,提出其潜在的问题及应用前景。     

真菌核酸的一种快速提取方法

在总结多种真菌DNA和RNA提取方法的基础上，发展了一种提取真菌核酸新方法，与其它方法相比，该方法具有快速、操作简便等特点，而且提取DNA和RNA步骤基本一致，用该方法提取的DNA完整、纯度高，可用于PR、限制性内切酶酶切和Southern杂交等分子生物学操作；提取RNA产量高，RNA无降解，纯度高，适用Northern和cDNA合成等分子生物学操作。     

中度嗜盐菌Halomonas sp.BYS-1耐盐相关DNA片段的克隆

通过固体亚硝基胍诱变获得了Halom onassp.BYS-1的盐敏感突变株BYS-1M.以pBBR1MCS-2为载体在E.coliDH5α中构建了BYS-1的基因文库.以文库菌E.coliDH5α(pBBR-X)为供体菌、E.coliWD803(pRK2013)为辅助菌、BYS-1M为受体菌进行三亲接合,筛选到了恢复耐盐性能的接合子HR-23,提取接合子HR-23的重组质粒pHR23,酶切确定其插入的耐盐相关DNA片段大小分为5.4 kb.该片段为Halom onassp.BYS-1耐盐相关基因的克隆奠定了基础.图5表1参14     

Accumulation and phytotoxicity of technical hexabromocyclododecane in maize

To investigate the accumulation and phytotoxicity of technical hexabromocyclododecane(HBCD)in maize,young seedlings were exposed to solutions of technical HBCD at different concentrations.The uptake kinetics showed that the HBCD concentration reached an apparent equilibrium within 96 hr,and the accumulation was much higher in roots than in shoots.HBCD accumulation in maize had a positive linear correlation with the exposure concentration.The accumulation of different diastereoisomers followed the orderγ-HBCDβ-HBCDα-HBCD.Compared with their proportions in the technical HBCD exposure solution,the diastereoisomer contribution increased forβ-HBCD and decreased forγ-HBCD in both maize roots and shoots with exposure time,whereas the contribution ofα-HBCD increased in roots and decreased in shoots throughout the experimental period.These results suggest the diastereomer-specific accumulation and translocation of HBCD in maize.Inhibitory effects of HBCD on the early development of maize followed the order of germination rateroot biomass≥root elongationshoot biomass≥shoot elongation.Hydroxyl radical(OH)and histone H2AX phosphorylation(γ-H2AX)were induced in maize by HBCD exposure,indicative of the generation of oxidative stress and DNA double-strand breaks in maize.An OH scavenger inhibited the expression ofγ-H2AX foci in both maize roots and shoots,which suggests the involvement of OH generation in the HBCD-induced DNA damage.The results of this study will offer useful information for a more comprehensive assessment of the environmental behavior and toxicity of technical HBCD.     

Molecular toxicity and defense mechanisms induced by silver nanoparticles in Drosophila melanogaster

The widely use of silver nanoparticles (AgNPs) as antimicrobial agents gives rise to potential environmental risks. AgNPs exposure have been reported to cause toxicity in animals. Nevertheless, the known mechanisms of AgNPs toxicity are still limited. In this study, we systematically investigated the toxicity of AgNPs exposure using Drosophila melanogaster. We show here that AgNPs significantly decreased Drosophila fecundity, the third-instar larvae weight and rates of pupation and eclosion in a dose-dependent manner. AgNPs reduced fat body cell viability in MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays. AgNPs caused DNA damage in hemocytes and S2 cells. Interestingly, the mRNA levels of the entire metallothionein gene family were increased under AgNPs exposure as determined by RNA-seq analysis and validated by qRT-PCR, indicating that Drosophila responded to the metal toxicity of AgNPs by producing metallothioneins for detoxification. These findings provide a better understanding of the mechanisms of AgNPs toxicity and may provide clues to effect on other organisms, including humans.     

Long‐Term Impacts of Poaching on Relatedness,Stress Physiology,and Reproductive Output of Adult Female African Elephants

Abstract: Widespread poaching prior to the 1989 ivory ban greatly altered the demographic structure of matrilineal African elephant (Loxodonta africana) family groups in many populations by decreasing the number of old, adult females. We assessed the long‐term impacts of poaching by investigating genetic, physiological, and reproductive correlates of a disturbed social structure resulting from heavy poaching of an African elephant population in Mikumi National Park, Tanzania, prior to 1989. We examined fecal glucocorticoid levels and reproductive output among 218 adult female elephants from 109 groups differing in size, age structure, and average genetic relatedness over 25 months from 2003 to 2005. The distribution in group size has changed little since 1989, but the number of families with tusked old matriarchs has increased by 14.2%. Females from groups that lacked an old matriarch, first‐order adult relatives, and strong social bonds had significantly higher fecal glucocorticoid values than those from groups with these features (all females R²= 0.31; females in multiadult groups R²= 0.46). Females that frequented isolated areas with historically high poaching risk had higher fecal glucocorticoid values than those in low poaching risk areas. Females with weak bonds and low group relatedness had significantly lower reproductive output (R²[U]=0.21). Females from disrupted groups, defined as having observed average group relatedness 1 SD below the expected mean for a simulated unpoached family, had significantly lower reproductive output than females from intact groups, despite many being in their reproductive prime. These results suggest that long‐term negative impacts from poaching of old, related matriarchs have persisted among adult female elephants 1.5 decades after the 1989 ivory ban was implemented.