Female Aedes aegypti mosquitoes infect more than 400 million people each year with dangerous viral pathogens including dengue, yellow fever, Zika and chikungunya. Progress in understanding the biology of mosquitoes and developing the tools to fight them has been slowed by the lack of a high-quality genome assembly. Here we combine diverse technologies to produce the markedly improved, fully re-annotated AaegL5 genome assembly, and demonstrate how it accelerates mosquito science. We anchored physical and cytogenetic maps, doubled the number of known chemosensory ionotropic receptors that guide mosquitoes to human hosts and egg-laying sites, provided further insight into the size and composition of the sex-determining M locus, and revealed copy-number variation among glutathione S-transferase genes that are important for insecticide resistance. Using high-resolution quantitative trait locus and population genomic analyses, we mapped new candidates for dengue vector competence and insecticide resistance. AaegL5 will catalyse new biological insights and intervention strategies to fight this deadly disease vector.

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Ticks transmit more pathogens to humans and animals than any other arthropod. We describe the 2.1 Gbp nuclear genome of the tick, Ixodes scapularis (Say), which vectors pathogens that cause Lyme disease, human granulocytic anaplasmosis, babesiosis and other diseases. The large genome reflects accumulation of repetitive DNA, new lineages of retro-transposons, and gene architecture patterns resembling ancient metazoans rather than pancrustaceans. Annotation of scaffolds representing ∼57% of the genome, reveals 20,486 protein-coding genes and expansions of gene families associated with tick–host interactions. We report insights from genome analyses into parasitic processes unique to ticks, including host ‘questing', prolonged feeding, cuticle synthesis, blood meal concentration, novel methods of haemoglobin digestion, haem detoxification, vitellogenesis and prolonged off-host survival. We identify proteins associated with the agent of human granulocytic anaplasmosis, an emerging disease, and the encephalitis-causing Langat virus, and a population structure correlated to life-history traits and transmission of the Lyme disease agent.

Ionotropic GABA receptors are abundant in both vertebrate and invertebrate nervous systems, where they mediate rapid, mostly inhibitory synaptic transmission. A GABA-gated chloride channel subunit from Drosophila melanogaster [Resistant to Dieldrin (RDL)] has been cloned, functionally expressed, and found to exhibit many aspects of the pharmacology of native, bicuculline-insensitive insect GABA receptors. RDL is the target of the commercially important insecticide fipronil. A point mutation in the channel-lining region of the RDL molecule is known to underlie most cases of resistance to insecticides acting on GABA receptors. RDL is widely distributed throughout the insect nervous system, but the subunit composition of RDLcontaining in native receptors is unknown. It is possible that in some instances, RDL coexpresses with glutamate-gated chloride channel subunits. Other ionotropic receptor subunits (LCCH3 and GRD) form GABA-gated cation channels when heterologously expressed. Interest in RDL as a model ligandgated anion channel has been enhanced by the recent discovery of pre-mRNA A-to-I editing, which, together with alternative splicing, adds to the functional diversity of this GABA receptor subunit.Ionotropic GABA receptor molecules (GABARs) are members of the dicysteine-loop ('Cys-loop') superfamily of neurotransmitter receptors, which also includes nicotinic acetylcholine receptors, type 3 5-hydroxytryptamine receptors, and glycine receptors (Karlin and Akabas, 1995;Karlin, 2002;Olsen et al., 2004). Ionotropic GABARs are pentameric proteins. Each polypeptide subunit possesses a long N-terminal extracellular domain containing residues that contribute to the neurotransmitter binding site and four transmembrane regions (M1-M4), the second of which (M2) provides many of the residues that line the integral chloride channel (Whiting, 2003;Kim et al., 2004;Darlison et al., 2005). Vertebrate ionotropic GABARs may be divided into two pharmacological categories: bicuculline-sensitive GABA A receptors (composed of ␣ 1-6 , ␤ 1-3 , ␥ 1-3 , ␦, ⑀, , and 1-3 subunits and allosterically modulated by benzodiazepines and barbiturates as well as pregnane steroids) and bicuculline-insensitive GABA C receptors (composed of the three known isoforms of the subunit and insensitive to the majority of modulators of GABA A receptors) (Mustafa, 1995;Sieghart, 1995;McKernan and Whiting, 1996;Whiting, 2003;Connolly and Wafford, 2004;Rudolph and Mohler, 2004). This division into A and C subtypes is difficult to reconcile with recent findings on GABARs in brainstem neurons, which are composed of 1 subunits coexpressed with ␣1 and ␥2 subunits (Milligan et al., 2004) to yield receptors with properties of both GABA A and GABA C subtypes. Furthermore, GABA A and GABA B receptors, which differ structurally and in their signaling mechanisms, may be closely functionally coupled. This is supported by the recent finding that the GABA A ␥2S subunit forms a complex with GABA B R1 subunits (thereby enhancing GABA B receptor trafficking to the c...