Simulation of gene pyramiding in Drosophila melanogaster

Gene pyramiding has been successfully practiced in plant breeding for developing new breeds or lines in which favorable genes from several different lines were integrated.But it has not been used in animal breeding,and some theoretical investigation and simulation analysis with respect to its strategies,feasibility and efficiency are needed before it can be implemented in animals.In this study,we used four different pure fines of Drosophila melanogaster,each of which is homozygous at a specific mutant gene with a visible effect on phenotype,to simulate the gene pyramiding process and analyze the duration and population size required in different pyramiding strategies.We finally got the ideal individuals,which are homozygous at the four target genes simultaneously.This study demonstrates that gene pyramiding is feasible in animal breeding and the interaction between genes may affect the final results.     

Simulation of gene pyramiding in Drosophila melanogaster

Gene pyramiding has been successfully practiced in plant breeding for developing new breeds or lines in which favorable genes from several different lines were integrated.But it has not been used in animal breeding,and some theoretical investigation and simulation analysis with respect to its strategies,feasibility and efficiency are needed before it can be implemented in animals.In this study,we used four different pure lines of Drosophila melanogaster,each of which is homozygous at a specific mutant gene ...     

不同温度条件下果蝇染色体结构的变化

将黑腹果蝇Drosophila melanogaster置于不同温度环境下培养,应用改良苯酚品红染色法制片.发现其唾腺染色体在不同的温度培养条件下,分布于染色体上的膨松区域有明显变化,在15℃和27℃下染色体的变化区域明显较19℃和23℃下的多,这些区域都与机体调控和表达的基因相关.这可能是机体对不适生存条件采取的保护措施所引起更多的染色体或基因发生变化的结果.对不同温度条件下部分染色体膨松区域的特殊基因作了简单讨论.     

汉黄芩苷通过调节抗氧化基因表达和机体代谢延长果蝇寿命

为探究汉黄芩苷是否具有抗衰老作用,本研究以果蝇为模型,考察汉黄芩苷对果蝇自然寿命的影响。采用RT-PCR和UPLC-MS/MS 代谢组学技术,探索汉黄芩苷发挥抗衰老作用的潜在机制。结果显示,0.02和0.5 mg/mL 汉黄芩苷均可整体延长果蝇寿命,并能够分别延长果蝇平均寿命5.64%和5.39%,延长最高寿命2.74%和5.12%;与30 d组相比,汉黄芩苷能够显著上调果蝇体内抗氧化酶基因SOD1、SOD2和CAT的表达水平,下调MTH的表达水平。果蝇代谢组学分析共找到17个潜在生物标志物,主要参与氨基酸代谢（D-谷氨酰胺和D-谷氨酸代谢,丙氨酸、天冬氨酸和谷氨酸代谢,精氨酸和脯氨酸代谢,缬氨酸、亮氨酸和异亮氨酸代谢）和能量代谢（氮代谢）。该结果表明,汉黄芩苷延缓衰老与上调抗氧化基因表达和调控不同代谢途径有关。     

黑腹果蝇的性别控制

性别的形成包括两个过程,即性别决定和性别分化。果蝇的性别控制研究包括性别决定、性别分化、性别鉴定、性别诱导和性别控制5个方面。性别决定是在两种不同发育途径之间的选择,它提供了一个研究基因调控的模式系统。果蝇的性别决定问题已经研究得相当详细［1］。性别分化是使胚胎向着雌性或雄性发育的过程,决定了性别表型。果蝇的性别分化也取得了不少研究成果。近年来,许多重要的性别调控基因已被克隆和鉴定。随着果蝇基因组全序列测定的完成,果蝇的性别控制研究将会更为深入而完善。本文对与黑腹果蝇性别决定和性别分化相关的一些问题进行综述。     

果蝇蛋白质组学研究进展

蛋白质组学旨在阐明基因组所表达的真正执行生命活动的全部蛋白质的表达规律和生物功能。随着人类基因组学计划的逐渐成熟,分子水平的实验技术不断发展,蛋白质组学的研究被提高到了前所未有的高度。果蝇是生命科学领域最为常用的一种模式生物,长期的系统研究也使果蝇的基因组成为至今注释最好的基因组之一,为功能基因组研究奠定了基础。但由于技术的限制,迄今有关果蝇蛋白质组学研究的报道尚不多见。近年来果蝇蛋白质组学的研究主要包括表达谱、修饰谱、比较蛋白质组学和疾病模型蛋白质组等四个方向,为进一步开展人类疾病临床蛋白质组学研究奠定了基础。     

Age-dependent behavior loss in adult Drosophila melanogaster

The use of Drosophila as an organism in which to study aging has been limited by the fact that few biomarkers of aging exist in the adult. In this paper we examine behavior loss relative to longevity in wild-type populations maintained at 22°C and 29°C to determine whether behavior loss—that is, loss of ability to perform certain innate behavioral responses within a defined test interval—can be used as biomarkers of aging. We find that under controlled conditions behavior loss can be used as a landmark of aging in populations maintained at either 22°C or 29°C. The ability to perform normal geotactic and phototactic responses is lost during the reproductive phase of the adult populations, whereas motor activity is not lost until well into the death phase. We feel that the use of behavior loss, together with other parameters of longevity in Drosophila, will allow comparisons to be made between different strains or between different environmental conditions to test their effect on aging. In the companion paper we demonstrate the use of behavior loss to identify a mutation which may accelerate the aging process.     

Differential requirements for the neurogenic gene almondex during Drosophila melanogaster development

During early development, the neurogenic genes of Drosophila melanogaster are involved in the control of cell fates in the neurectoderm; almondex (amx) belongs to this category of genes. We have identified the amx locus and rescued the amx embryonic neurogenic phenotype with a 1.5 kb DNA fragment. Using a small deficiency, we generated a new amx mutant background called amx(m), which is a null allele. Besides the characteristic neurogenic maternal effect caused by loss of amx, amx(m) flies display a new imaginal phenotype resembling loss of function of Notch. We describe amx-induced misregulation of the Notch pathway target E(spl) m7 in embryos and genetic interactions between amx and Notch pathway mutants in adult flies. These data show that wildtype amx acts as a novel positive regulator of the Notch pathway and is required at different levels during development.     

果蝇衰老的调控机制

衰老是一个复杂的生物学过程,涉及到有害物质的积累导致整体生命功能的下降,生物的生理状况逐渐恶化,最终导致疾病和死亡。黑腹果蝇Drosophila melanogaster作为最重要的遗传学工具之一,近年来常被用于衰老的研究,以阐明衰老的发生与发展机制。本文结合本实验室的研究进展,综述了果蝇寿命调控的生理生化机制,如保幼激素、胰岛素/类胰岛素生长因子、TOR信号网络、腺苷酸活化蛋白激酶信号通路、热量限制和饮食限制、氧化应激、小分子RNA以及鞘脂类代谢都会对果蝇的寿命产生影响。除此之外,基因调控网络研究还能够发现潜在的与长寿相关的基因组区域,将有可能发现更多寿命相关基因。以果蝇为模式生物的研究,对于其他昆虫衰老、存活等种群生物学问题的研究以及天敌、益虫保育和害虫控制,具有十分重要的指导意义。     

逆境诱导水稻谷胱甘肽合成酶基因的表达研究

用RACE方法获得了全长的水稻谷胱甘肽合成酶(GS)基因的cDNA,并命名为OsGS(GeneBankaccession No.:AY453405)。该cDNA全长1 892 bp,编码一个由540个氨基酸组成的多肽,预测其氨基端(N端)含有一段定位叶绿体的信号肽。比较水稻基因组定位结果表明OsGS基因位于水稻12号染色体短臂上,转录区全长6 321 bp,由12个外显子和11个内含子组成。通过RT-PCR对OsGS在水稻正常生长条件和逆境条件下的表达进行了研究。结果表明,在正常生长条件下,OsGS在水稻幼苗的根和叶以及抽穗期水稻的根中表达;但不在抽穗期水稻的叶、茎和幼穗中表达,这显示OsGS在水稻中的表达具有发育和组织特异性。利用抽穗期水稻的叶片为材料,经高温、干旱和重金属逆境处理后,OsGS在抽穗期叶片中的转录被诱导表达;而在盐、低温、伤害逆境下则不被诱导。在轻度和中度干旱胁迫4 h后OsGS基因可被诱导表达。外源ABA处理也能够提高OsGS的转录水平,这显示OsGS可能是依赖ABA信号途径的环境胁迫诱导基因。     

黑腹果蝇黑条体突变体的求偶行为

黑腹果蝇Drosophila melanogaster黑条体果蝇(e^bsr)与黑檀体果蝇(e)为同一个基因(ebony)的不同突变体, 两者具有相似的形态表型, 但行为特征表现出明显的差异。本研究以黑条体、 黑檀体和野生型果蝇为研究对象, 首先检测果蝇的视力和活跃度, 再采用不同交配组合进行求偶成功率、交配时间和求偶模式的分析。结果表明: 黑条体果蝇视力与活跃度与野生型果蝇比较无显著差异; 黑条体果蝇的交配成功率和交配潜伏期与野生型果蝇不存在显著的差异; 黑檀体果蝇的交配成功率和交配潜伏期与野生型果蝇存在极显著的差异（P<0.000）。黑条体果蝇表现出异于黑檀体果蝇的活跃度和交配活力, 可能是由于黑条体果蝇ebony基因的新突变导致了果蝇体内多巴胺水平异常, 从而形成了黑条体果蝇独特的求偶模式。     

Evidence of gene conversion associated with a selective sweep in Drosophila melanogaster

Since Drosophila melanogaster colonized Europe from tropical Africa 10 to 15 thousand years ago, it is expected that adaptation has played a major role in this species in recent times. A previously conducted multilocus scan of noncoding DNA sequences on the X chromosome in an ancestral and a derived population of D. melanogaster revealed that some loci have been affected by directional selection in the European population. We investigated if the pattern of DNA sequence polymorphism in a region surrounding one of these loci can be explained by a hitchhiking event. We found strong evidence that the studied region around the gene unc-119 was shaped by a recent selective sweep, including a valley of reduced heterozygosity of 83.4 kb, a skew in the frequency spectrum, and significant linkage disequilibrium on one side of the valley. This region, however, was interrupted by gene conversion events leading to a strong haplotype structure in the center of the valley of reduced variation.     

Correlation of phenotypes of the apterous mutation in Drosophila melanogaster

The apterous (ap) mutant in Drosophila melanogaster exhibits phenotypes of wing deficiency, precocious adult death, and nonvitellogenic oocyte development. The latter phenotype previously has been shown to result from juvenile hormone (JH) deficiency in the adult stage. To explore the relationship between the hormone deficiency and the other phenotypes, the expression of each phenotype was measured in five alleles of ap (including a new, chemically-induced allele, ap^77f) as wing length, survival five days after eclosion, and initiation and progress of vitellogenic oocyte development. No correlation could be found between severity of wing phenotype and that of precocious adult death or nonvitellogenesis. However, the latter phenotypes were correlated in both ap homozygotes and allelic heterozygotes, since adults that survive have wild-type vitellogenesis, and those fated for precocious death fail to develop vitellogenic oocytes. These results indicate that no relationship exists between wing and JH deficiencies, but that precocious adult death is related to hormone deficiency — probably through pleiotropy, rather than through causality.     

Gene expression patterns accompanying a dietary shift in Drosophila melanogaster

The ability of many organisms to switch to new hosts can be critical to their survival in the wild. However, the genetic mechanisms underlying such shifts are poorly understood. In this study, we used complementary DNA (cDNA) microarrays to ask if changes in gene expression are observed in response to a dietary shift in Drosophila melanogaster, a dietary generalist. We found significant and repeatable differential expression in a number of genes related to metabolic function and stress, suggesting that a functional genomics approach will be useful in seeking loci involved in the ability of flies to utilize different resources.