Solving the 250-year-old mystery of the origin and global spread of the German cockroach, Blattella germanica.

The origin of the German cockroach, Blattella germanica, is enigmatic, in part because it is ubiquitous worldwide in human-built structures but absent from any natural habitats. The first historical records of this species are from ca. 250 years ago (ya) from central Europe (hence its name). However, recent research suggests that the center of diversity of the genus is Asian, where its closest relatives are found. To solve this paradox, we sampled genome-wide markers of 281 cockroaches from 17 countries across six continents. We confirm that B. germanica evolved from the Asian cockroach Blattella asahinai approximately 2,100 ya, probably by adapting to human settlements in India or Myanmar. Our genomic analyses reconstructed two primary global spread routes, one older, westward route to the Middle East coinciding with various Islamic dynasties (~1,200 ya), and another younger eastward route coinciding with the European colonial period (~390 ya). While Europe was not central to the early domestication and spread of the German cockroach, European advances in long-distance transportation and temperature-controlled housing were likely important for the more recent global spread, increasing chances of successful dispersal to and establishment in new regions. The global genetic structure of German cockroaches further supports our model, as it generally aligns with geopolitical boundaries, suggesting regional bridgehead populations established following the advent of international commerce.

Next Generation Sequencing Revolutionizes Organismal Biology Research in Bats.

The advent of next generation sequencing technologies (NGS) has greatly accelerated our understanding of critical aspects of organismal biology from non-model organisms. Bats form a particularly interesting group in this regard, as genomic data have helped unearth a vast spectrum of idiosyncrasies in bat genomes associated with bat biology, physiology, and evolution. Bats are important bioindicators and are keystone species to many eco-systems. They often live in proximity to humans and are frequently associated with emerging infectious diseases, including the COVID-19 pandemic. Nearly four dozen bat genomes have been published to date, ranging from drafts to chromosomal level assemblies. Genomic investigations in bats have also become critical towards our understanding of disease biology and host-pathogen coevolution. In addition to whole genome sequencing, low coverage genomic data like reduced representation libraries, resequencing data, etc. have contributed significantly towards our understanding of the evolution of natural populations, and their responses to climatic and anthropogenic perturbations. In this review, we discuss how genomic data have enhanced our understanding of physiological adaptations in bats (particularly related to ageing, immunity, diet, etc.), pathogen discovery, and host pathogen co-evolution. In comparison, the application of NGS towards population genomics, conservation, biodiversity assessment, and functional genomics has been appreciably slower. We reviewed the current areas of focus, identifying emerging topical research directions and providing a roadmap for future genomic studies in bats.

Hybrid de novo genome assembly of the sexually dimorphic Lady Amherst's pheasant.

Pheasants are an important group of birds, valued for their economic benefit as poultry birds, game birds, and as ornamental species for their plumage. Lady Amherst's pheasant Chrysolophus amherstiae is an ornamental species, valued for its elaborate and beautiful plumage. In this study, we present a high-quality de novo hybrid genome assembly of C. amherstiae. Previous attempts to sequence the genome of this species resulted in draft-level assemblies, which are not available in the public domain. Using a combination of Illumina short reads and Oxford Nanopore's long-reads, we assembled a high-quality genome of N50 ~3.9 Mb and near complete BUSCO assessment. We observed a correlation between effective population size and past climatic conditions, with an increase in population size during the warm interglacial periods. We further observed significant fluctuations in genes involved with the immune system and visual perception. C. amherstiae is a highly dimorphic species, and significant fluctuations in gene families involved in immune response, visual perception, among others, suggesting a role of mate choice and sexual selection in the evolution and maintenance of exaggerated traits in the males.

Correction: Filovirus-reactive antibodies in humans and bats in Northeast India imply zoonotic spillover.

[This corrects the article DOI: 10.1371/journal.pntd.0007733.].

Filovirus-reactive antibodies in humans and bats in Northeast India imply zoonotic spillover.

Bats are reservoirs for several zoonotic pathogens, including filoviruses. Recent work highlights the diversity of bat borne filoviruses in Asia. High risk activities at the bat-human interface pose the threat of zoonotic virus transmission. We present evidence for prior exposure of bat harvesters and two resident fruit bat species to filovirus surface glycoproteins by screening sera in a multiplexed serological assay. Antibodies reactive to two antigenically distinct filoviruses were detected in human sera and to three individual filoviruses in bats in remote Northeast India. Sera obtained from Eonycteris spelaea bats showed similar patterns of cross-reactivity as human samples, suggesting them as the species responsible for the spillover. In contrast, sera from Rousettus leschenaultii bats reacted to two different virus glycoproteins. Our results indicate circulation of several filoviruses in bats and the possibility for filovirus transmission from bats to humans.