In the wake of constant improvements in sequencing technologies, numerous insect genomes have been sequenced. Currently, 1219 insect genome-sequencing projects have been registered with the National Center for Biotechnology Information, including 401 that have genome assemblies and 155 with an official gene set of annotated protein-coding genes. Comparative genomics analysis showed that the expansion or contraction of gene families was associated with well-studied physiological traits such as immune system, metabolic detoxification, parasitism and polyphagy in insects. Here, we summarize the progress of insect genome sequencing, with an emphasis on how this impacts research on pest control. We begin with a…
Multispecies host-parasite evolution is common, but how parasites evolve after speciating remains poorly understood. Shared evolutionary history and physiology may propel species along similar evolutionary trajectories whereas pursuing different strategies can reduce competition. We test these scenarios in the economically important association between honey bees and ectoparasitic mites by sequencing the genomes of the sister mite species Varroa destructor and Varroa jacobsoni. These genomes were closely related, with 99.7% sequence identity. Among the 9,628 orthologous genes, 4.8% showed signs of positive selection in at least one species. Divergent selective trajectories were discovered in conserved chemosensory gene families (IGR, SNMP), and…
Background New sequencing technologies have lowered financial barriers to whole genome sequencing, but resulting assemblies are often fragmented and far from textquoteleftfinishedtextquoteright. Updating multi-scaffold drafts to chromosome-level status can be achieved through experimental mapping or re-sequencing efforts. Avoiding the costs associated with such approaches, comparative genomic analysis of gene order conservation (synteny) to predict scaffold neighbours (adjacencies) offers a potentially useful complementary method for improving draft assemblies.Results We employed three gene synteny-based methods applied to 21 Anopheles mosquito assemblies to produce consensus sets of scaffold adjacencies. For subsets of the assemblies we integrated these with additional supporting data to confirm…
Kodamaea ohmeri is a symbiont of the small hive beetle (SHB), which is a scavenger of honey bee colonies. The SHB causes absconding of the economically important honey bee (Apis mellifera) and deposits K. ohmeri in the honeycomb. We describe long-read sequencing and further analyses of the K. ohmeri genome.
The small hive beetle (SHB) is an opportunistic parasite that feeds on bee larvae, honey, and pollen. While SHBs can also feed on fruit and other plant products, like its plant-feeding relatives, SHBs prefer to feed on hive resources and only reproduce inside bee colonies. As parasites, SHBs are inevitably exposed to bee-associated microbes, either directly from the bees or from the hive environment. These microbes have unknown impacts on beetles, nor is it known how extensively beetles transfer microbes among their bee hosts. To identify sets of beetle microbes and the transmission of microbes from bees to beetles, a…
The stingless bee Melipona bicolor is the only bee in which true polygyny occurs. Its mitochondrial genome was first sequenced in 2008, but it was incomplete and no information about its transcription was known. We combined short and long reads of M. bicolor DNA with RNASeq data to obtain insights about mitochondrial evolution and gene expression in bees. The complete genome has 15,001?bp, including a control region of 255?bp that contains all conserved structures described in honeybees with the highest AT content reported so far for bees (98.1%), displaying a compact but functional region. Gene expression control is similar to…
Morella rubra, red bayberry, is an economically important fruit tree in south China. Here, we assembled the first high-quality genome for both a female and a male individual of red bayberry. The genome size was 313-Mb, and 90% sequences were assembled into eight pseudo chromosome molecules, with 32 493 predicted genes. By whole-genome comparison between the female and male and association analysis with sequences of bulked and individual DNA samples from female and male, a 59-Kb region determining female was identified and located on distal end of pseudochromosome 8, which contains abundant transposable element and seven putative genes, four of them…
Haematococcus pluvialis is a freshwater species of Chlorophyta, family Haematococcaceae. It is well known for its capacity to synthesize high amounts of astaxanthin, which is a strong antioxidant that has been utilized in aquaculture and cosmetics. To improve astaxanthin yield and to establish genetic resources for H. pluvialis, we performed whole-genome sequencing, assembly, and annotation of this green microalga. A total of 83.1 Gb of raw reads were sequenced. After filtering the raw reads, we subsequently generated a draft assembly with a genome size of 669.0?Mb, a scaffold N50 of 288.6?kb, and predicted 18,545 genes. We also established a robust…
Multispecies host-parasite evolution is common, but how parasites evolve after speciating remains poorly understood. Shared evolutionary history and physiology may propel species along similar evolutionary trajectories whereas pursuing different strategies can reduce competition. We test these scenarios in the economically important association between honey bees and ectoparasitic mites by sequencing the genomes of the sister mite species Varroa destructor and Varroa jacobsoni. These genomes were closely related, with 99.7% sequence identity. Among the 9,628 orthologous genes, 4.8% showed signs of positive selection in at least one species. Divergent selective trajectories were discovered in conserved chemosensory gene families (IGR, SNMP), and…
The ability to generate long sequencing reads and access long-range linkage information is revolutionizing the quality and completeness of genome assemblies. Here we use a hybrid approach that combines data from four genome sequencing and mapping technologies to generate a new genome assembly of the honeybee Apis mellifera. We first generated contigs based on PacBio sequencing libraries, which were then merged with linked-read 10x Chromium data followed by scaffolding using a BioNano optical genome map and a Hi-C chromatin interaction map, complemented by a genetic linkage map.Each of the assembly steps reduced the number of gaps and incorporated a substantial…
PacBio Sequencing is characterized by very long sequence reads (averaging > 10,000 bases), lack of GC-bias, and high consensus accuracy. These features have allowed the method to provide a new gold standard in de novo genome assemblies, producing highly contiguous (contig N50 > 1 Mb) and accurate (> QV 50) genome assemblies. We will briefly describe the technology and then highlight the full workflow, from sample preparation through sequencing to data analysis, on examples of insect genome assemblies, and illustrate the difference these high-quality genomes represent with regard to biological insights, compared to fragmented draft assemblies generated by short-read sequencing.
The citrus fruit fly Bactrocera (Tetradacus) minax is a major and devastating agricultural pest in Asian subtropical countries. Previous studies have shown that B. minax interacts with hosts via an efficient chemosensory system. However, knowledge regarding the molecular components of the B. minax chemosensory system has not yet been well established. Herein, based on our newly generated whole-genome dataset for B. minax and by comparison with the characterized genomes of 6 other fruit fly species, we identified, for the first time, a total of 25 putative odorant-binding receptors (OBPs), 4 single-copy chemosensory proteins (CSPs) and 53 candidate odorant receptors (ORs).…
Herbal medicine is a major component of complementary and alternative medicine, contributing significantly to the health of many people and communities. Quality control of herbal medicine is crucial to ensure that it is safe and sound for use. Here, we investigated a comprehensive quality evaluation system for a classic herbal medicine, Danggui Buxue Formula, by applying genetic-based and analytical chemistry approaches to authenticate and evaluate the quality of its samples. For authenticity, we successfully applied two novel technologies, third-generation sequencing and PCR-DGGE (denaturing gradient gel electrophoresis), to analyze the ingredient composition of the tested samples. For quality evaluation, we used…
Over the past decade, the field of genomics has seen such drastic improvements in sequencing chemistries that high-throughput sequencing, or next-generation sequencing (NGS), is being applied to generate data across many disciplines. NGS instruments are becoming less expensive, faster, and smaller, and therefore are being adopted in an increasing number of laboratories, including clinical laboratories. Thus far, clinical use of NGS has been mostly focused on the human genome, for purposes such as characterizing the molecular basis of cancer or for diagnosing and understanding the basis of rare genetic disorders. There are, however, an increasing number of examples whereby NGS…
Impressive progress has been made in the field of Next Generation Sequencing (NGS). Through advancements in the fields of molecular biology and technical engineering, parallelization of the sequencing reaction has profoundly increased the total number of produced sequence reads per run. Current sequencing platforms allow for a previously unprecedented view into complex mixtures of RNA and DNA samples. NGS is currently evolving into a molecular microscope finding its way into virtually every fields of biomedical research. In this chapter we review the technical background of the different commercially available NGS platforms with respect to template generation and the sequencing reaction…