Chromosome variations inXenopsylla astia Rothschild, 1911 (Siphonaptera). A preliminary report

Thomas, Cheriyan; Prasad, Rajendra

doi:10.1007/bf01932337

Cited by 2 publications

(1 citation statement)

References 9 publications

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“…A large fraction of the total assembly (85.6% or 654 Mb) was found in nine scaffolds (all greater than 10 Mb, hereafter BIG9), while the remaining 14.4% (119.8 Mb) comprised scaffolds less than 1 Mb in length; therefore, we suggest the C. felis genome contains nine chromosomes (Fig. 1a), an estimate consistent with previously determined flea karyotypes [28,29]. The 3724 shorter scaffolds (all less than 1 Mb) mapped back to unique locations on BIG9 scaffolds (Additional file 1: Fig.…”

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confidence: 88%

A chromosome-level assembly of the cat flea genome uncovers rampant gene duplication and genome size plasticity

et al. 2020

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Background Fleas (Insecta: Siphonaptera) are small flightless parasites of birds and mammals; their blood-feeding can transmit many serious pathogens (i.e., the etiological agents of bubonic plague, endemic and murine typhus). The lack of flea genome assemblies has hindered research, especially comparisons to other disease vectors. Accordingly, we sequenced the genome of the cat flea, Ctenocephalides felis, an insect with substantial human health and veterinary importance across the globe. Results By combining Illumina and PacBio sequencing of DNA derived from multiple inbred female fleas with Hi-C scaffolding techniques, we generated a chromosome-level genome assembly for C. felis. Unexpectedly, our assembly revealed extensive gene duplication across the entire genome, exemplified by ~ 38% of protein-coding genes with two or more copies and over 4000 tRNA genes. A broad range of genome size determinations (433–551 Mb) for individual fleas sampled across different populations supports the widespread presence of fluctuating copy number variation (CNV) in C. felis. Similarly, broad genome sizes were also calculated for individuals of Xenopsylla cheopis (Oriental rat flea), indicating that this remarkable “genome-in-flux” phenomenon could be a siphonapteran-wide trait. Finally, from the C. felis sequence reads, we also generated closed genomes for two novel strains of Wolbachia, one parasitic and one symbiotic, found to co-infect individual fleas. Conclusion Rampant CNV in C. felis has dire implications for gene-targeting pest control measures and stands to complicate standard normalization procedures utilized in comparative transcriptomics analysis. Coupled with co-infection by novel Wolbachia endosymbionts—potential tools for blocking pathogen transmission—these oddities highlight a unique and underappreciated disease vector.

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Section: Resultssupporting

confidence: 88%

A chromosome-level assembly of the cat flea genome uncovers rampant gene duplication and genome size plasticity

et al. 2020

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A chromosome-level assembly of the cat flea genome uncovers rampant gene duplication and genome size plasticity

Driscoll

Verhoeve

Gillespie

et al. 2020

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27Background: Fleas (Insecta: Siphonaptera) are small flightless parasites of birds and mammals; 28 their blood-feeding can transmit many serious pathogens (i.e. the etiological agents of bubonic 29 plague, endemic and murine typhus). The lack of flea genome assemblies has hindered research, 30 especially comparisons to other disease vectors. Accordingly, we sequenced the genome of the 31 cat flea, Ctenocephalides felis, an insect with substantial human health and veterinary importance 32 across the globe. 33Results: By combining Illumina and PacBio sequencing with Hi-C scaffolding techniques, we 34 generated a chromosome-level genome assembly for C. felis. Unexpectedly, our assembly 35 revealed extensive gene duplication across the entire genome, exemplified by ~38% of protein-36 coding genes with two or more copies and over 4,000 tRNA genes. A broad range of genome 37 size determinations (433-551 Mb) for individual fleas sampled across different populations 38 supports the widespread presence of fluctuating copy number variation (CNV) in C. felis. 39Similarly broad genome sizes were also calculated for individuals of Xenopsylla cheopis 40 (Oriental rat flea), indicating that this remarkable "genome-in-flux" phenomenon could be a 41 siphonapteran-wide trait. Nevertheless, cat flea genomes have not experienced substantial 42 inflation due to rampant CNV, nor do we find a significant reduction in gene families as has been 43 described for other parasites. Quizzically, individual fleas were found to be co-infected with 44 parasitic and symbiotic Wolbachia, both of which are novel strains unique to C. felis. Conclusion: Rampant CNV in C. felis has dire implications for gene-targeting pest control 46 measures and stands to complicate standard normalization procedures utilized in comparative 47 transcriptomics analysis. Coupled with paradoxical co-infection with novel Wolbachia 48 endosymbionts, which are potential tools for blocking pathogen transmission, these oddities 49 highlight a unique and underappreciated human disease vector. 50 51 Background 52 With over 2,500 described species, fleas (Hexapoda: Siphonaptera) are small (~3 mm) flightless 53 insects that parasitize mainly mammals and birds [1]. Diverging from Order Mecoptera 54 (scorpionflies and hangingflies) in the Jurassic period [2], fleas are one of 11 extant orders of 55Holometabola, a superorder of insects that collectively go through distinctive larval, pupal, and 56 adult stages. The limbless, worm-like flea larvae contain chewing mouthparts and feed primarily 57 on organic debris, while adult mouthparts are modified for piercing skin and sucking blood. 58Other adaptations to an ectoparasitic lifestyle include wing loss, extremely powerful hind legs for 59 jumping, strong claws for grasping, and a flattened body that facilitates movement on host fur 60 and feathers. 61The Oriental rat flea, Xenopsylla cheopis, and to a lesser extent the cat flea, Ctenocephalides 62 felis, transmit Yersinia pestis, the causative agent of bubonic plague [3][4][5]. Flea...

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Chromosome variations inXenopsylla astia Rothschild, 1911 (Siphonaptera). A preliminary report

Cited by 2 publications

References 9 publications

A chromosome-level assembly of the cat flea genome uncovers rampant gene duplication and genome size plasticity

A chromosome-level assembly of the cat flea genome uncovers rampant gene duplication and genome size plasticity

A chromosome-level assembly of the cat flea genome uncovers rampant gene duplication and genome size plasticity

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