Recurrent evolution of two competing haplotypes in an insect DNA virus

Abstract

1Hosts and viruses are constantly evolving in response to each other: as hosts attempt to suppress the virus, 2 the virus attempts to evade and suppress the host's immune system. This arms race results in the evolution 3 of novel pathways in both the host and virus to gain the upper hand. Here we describe the coevolution 4 between Drosophila species and a common and virulent DNA virus. We identify two distinct viral types 5 that differ 100-fold in viral titer in infected individuals, with similar effects across multiple species. Our 6 analysis suggests that one of the viral types appears to have recurrently evolved at least 4 times in the past 7 ~30,000 years, including in another geographically distinct species, due to the high effective mutation rate 8 which increases with titer. The higher titer viral type is associated with suppression of the host immune 9 system and an increased transmission rate compared to the low viral titer type. Both types are maintained 129 2016; PALMER et al. 2019).130 Among populations there is a positive correlation between the frequency of the High type and 131 overall DiNV infection frequency (Figure 1D, GLM logistic regression z-value = 6.104, p-value = 132 0.00883), suggesting that the High type may have a higher effective transmission rate, resulting in a 133 higher number of new individuals infected, per DiNV infected individual. The transmission rate appears 134 157 the frequency of the virus infection. E. Expression (in FPKM per viral particle) of gp83 increases with the 158 number of High DiNV haplotype SNPs. 159 160

Selection and demography shape genomic variation in a ‘Sky Island’ species

“…Interestingly, D. innubila is burdened by Drosophila innubila nudivirus (DiNV), a Nudivirus that infects 40-50% of individuals in the wild(Unckless 2011a;Hill and Unckless 2020). A close relative of the virus suppresses Toll-regulated AMPs in D. melanogaster(Palmer et al 2018;Hill and Unckless 2020), which might explain why the Toll pathway and AMPs are fast evolving in D. innubila. Five AMPs showed consistently positive DoS and selection effect values (which are also among the highest in the genome): four Bomanins and Listericin .…”

Caracterización de baculovirus autóctonos para el control de la oruga militar tardía (<i>Spodoptera frugiperda</i>)

“…DISCUSIÓN SNP presentes en SfMNPV son bialélicos y específicos para solo un aislamiento, lo que sugiere que estos SNP podrían utilizarse como herramientas de genotipado. Recientemente, se ha empleado la variación genómica entre distintos aislamientos de nudivirus con títulos virales diferentes para inferir posiciones en el genoma que están directamente asociadas con la virulencia, 186 un resultado que resalta la utilidad de la información genómica para predecir propiedades infectivas. Con el mayor acceso a tecnologías de secuenciación de alto rendimiento y la disponibilidad de herramientas computacionales para analizar los datos generados, creemos que la secuenciación de nuevos aislamientos de SfMNPV a través de diferentes escalas temporales y geográficas nos permitirán comprender de manera más precisa los determinantes moleculares de la patogenicidad de este virus.…”