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Background

Butterflies and moths are emerging as model organisms in genetics and evolutionary studies. The family Hesperiidae (skippers) was traditionally viewed as a sister to other butterflies based on its moth-like morphology and darting flight habits with fast wing beats. However, DNA studies suggest that the family Papilionidae (swallowtails) may be the sister to other butterflies including skippers. The moth-like features and the controversial position of skippers in Lepidoptera phylogeny make them valuable targets for comparative genomics.

Results

We obtained the 310 Mb draft genome of the Clouded Skipper (Lerema accius) from a wild-caught specimen using a cost-effective strategy that overcomes the high (1.6 %) heterozygosity problem. Comparative analysis of Lerema accius and the highly heterozygous genome of Papilio glaucus revealed differences in patterns of SNP distribution, but similarities in functions of genes that are enriched in non-synonymous SNPs. Comparison of Lepidoptera genomes revealed possible molecular bases for unique traits of skippers: a duplication of electron transport chain components could result in efficient energy supply for their rapid flight; a diversified family of predicted cellulases might allow them to feed on cellulose-enriched grasses; an expansion of pheromone-binding proteins and enzymes for pheromone synthesis implies a more efficient mate-recognition system, which compensates for the lack of clear visual cues due to the similarities in wing colors and patterns of many species of skippers. Phylogenetic analysis of several Lepidoptera genomes suggested that the position of Hesperiidae remains uncertain as the tree topology varied depending on the evolutionary model.

Conclusion

Completion of the first genome from the family Hesperiidae allowed comparative analyses with other Lepidoptera that revealed potential genetic bases for the unique phenotypic traits of skippers. This work lays the foundation for future experimental studies of skippers and provides a rich dataset for comparative genomics and phylogenetic studies of Lepidoptera.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1846-0) contains supplementary material, which is available to authorized users.  相似文献   
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Bst DNA聚合酶大片段作为一种常用的DNA聚合酶,因其独特的特点:能引发链置换反应、高保真、耐高温等,而成为一种重要的DNA多重置换扩增酶。目的:为减少成本,设计一种高产,方便且扩增活性高的Bst DNA聚合酶大片段表达体系;探究该酶应用于胃癌石蜡包埋组织基因组DNA的扩增条件。方法:采用p TWIN1质粒作为载体克隆表达Bst DNA聚合酶大片段,应用几丁质亲和层析柱纯化该酶,使用该酶对人类基因组DNA进行不同温度下扩增,探究其最适反应温度,并据此对胃癌石蜡包埋组织基因组DNA进行扩增。结果:由此得到的Bst DNA聚合酶大片段能运用于胃癌石蜡包埋组织基因组DNA的扩增,扩增效率可达200倍,并能应用于a CGH芯片。结论:扩增得到保真性高,覆盖基因组范围大的DNA扩增产物。该应用与a CGH结合,使得对少量的癌症石蜡包埋组织DNA样本进行全基因组扩增,并进行其基因拷贝数变异研究成为可能。  相似文献   
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交互网络(Internet)的发展为联网的计算机用户之间进行信息交流提供了有效途径.就分子生物学家而言,他们不仅可以利用电子邮件系统发送和接收信息,而且更重要的是能够存取大量的分子生物学数据库和软件.利用Internet可以开展多种序列分析作业,包括序列数据库的类似性检索、基因编码区鉴定和蛋白质二级结构分析等.一个数据库,例如GenBank,可以通过多种方式来存取:a.电子邮件文件服务器,b.文件传送协议(FTP),c.Gopher,WAIS或WWW等服务器-客户机(Server-Client)系统.专为分子生物学家设计的BIOSCI电子公告牌为研究人员开展学术讨论、寻求别人帮助和与数据库人员交流提供了极大的方便.  相似文献   
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Summary Among the fertile sugar beet lines with nuclear sterility maintenance genes, rf, in a homozygous recessive state, sublines capable of reverting spontaneously at a high rate to sterility were identified. Of 24 related fertile sublines studied, 6 were found to spontaneously revert to sterility with a frequency of about 19%. Genetic analysis confirmed the cytoplasmic nature of spontaneously arising sterility. Reversion to sterility in these sublines was accompanied by alterations in the mitochondrial genome structure: loss of the autonomously replicating minicircle c (1.3 kb) and changes in the restriction patterns of high-molecular-weight mitochondrial DNA (mtDNA). Southern hybridixation analysis with cloned minicircle c as a probe revealed no integration of this DNA molecule into the main mitochondrial and nuclear genomes of the revertants. Comparative BamHI and EcoRI restriction analysis of the mtDNA from the sterile revertants and fertile parental subline showed that the spontaneous reversion is accompanied by extensive genomic rearrangement. Southern blot analysis with cloned -subunit of F1-ATPase (atpA) and cytochrome c oxidase subunit II (COX II) genes as probes indicated that the changes in mtDNA accompanying spontaneous reversion to sterility involved these regions. The mitochondrial genomes of the spontaneous revertants and the sterile analogue were shown to be identical.  相似文献   
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Glycine latifolia (Benth.) Newell & Hymowitz (2= 40), one of the 27 wild perennial relatives of soybean, possesses genetic diversity and agronomically favorable traits that are lacking in soybean. Here, we report the 939‐Mb draft genome assembly of G. latifolia (PI 559298) using exclusively linked‐reads sequenced from a single Chromium library. We organized scaffolds into 20 chromosome‐scale pseudomolecules utilizing two genetic maps and the Glycine max (L.) Merr. genome sequence. High copy numbers of putative 91‐bp centromere‐specific tandem repeats were observed in consecutive blocks within predicted pericentromeric regions on several pseudomolecules. No 92‐bp putative centromeric repeats, which are abundant in G. max, were detected in G. latifolia or Glycine tomentella. Annotation of the assembled genome and subsequent filtering yielded a high confidence gene set of 54 475 protein‐coding loci. In comparative analysis with five legume species, genes related to defense responses were significantly overrepresented in Glycine‐specific orthologous gene families. A total of 304 putative nucleotide‐binding site (NBS)‐leucine‐rich‐repeat (LRR) genes were identified in this genome assembly. Different from other legume species, we observed a scarcity of TIR‐NBS‐LRR genes in G. latifolia. The G. latifolia genome was also predicted to contain genes encoding 367 LRR‐receptor‐like kinases, a family of proteins involved in basal defense responses and responses to abiotic stress. The genome sequence and annotation of G. latifolia provides a valuable source of alternative alleles and novel genes to facilitate soybean improvement. This study also highlights the efficacy and cost‐effectiveness of the application of Chromium linked‐reads in diploid plant genome de novo assembly.  相似文献   
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微生物菌种改良的新方法新策略   总被引:5,自引:1,他引:4  
自然分离得到的原始菌种远不能达到工业生产要求,通过菌种改良获得高产菌种是有效的手段。传统方法虽然无需了解过多遗传背景就能取得成效,但往往耗时费力。随着DNA重组技术、原生质体融合、组学研究的应用日益广泛,微生物菌种改良的新方法和新策略诸如代谢工程、基因组改组和系统生物技术、核糖体工程、表观遗传修饰等逐步发展起来。以下综述了近年来菌种改良相关领域方法和策略特别是首次报道的表观遗传修饰的最新进展。  相似文献   
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