Project description:Species paraphyly and social parasitism: phylogenomics, morphology, and geography clarify the evolution of the Pseudomyrmex elongatulus group (Hymenoptera: Formicidae), a Mesoamerican ant clade
Project description:Although situated ~400 km from the east coast of Africa, Madagascar exhibits cultural, linguistic, and genetic traits from both Southeast Asia and Eastern Africa. The settlement history remains contentious; we therefore used a grid-based approach to sample at high-resolution the genomic diversity (including maternal lineages, paternal lineages, and genome-wide data) across 257 villages and 2704 Malagasy individuals. We find a common Bantu and Austronesian descent for all Malagasy individuals with a limited paternal contribution from Europe and the Middle East. Admixture and demographic growth happened recently, suggesting a rapid settlement of Madagascar during the last millennium. However, the distribution of African and Asian ancestry across the island reveals that the admixture was sex biased and happened heterogeneously across Madagascar, suggesting independent colonization of Madagascar from Africa and Asia rather than settlement by an already-admixed population. In addition, there are geographic influences on the present genomic diversity, independent of the admixture, showing that a few centuries is sufficient to produce detectable genetic structure in human populations.
Project description:To make clear the genetic diversity and virulence evolution at the genome-wide level of A. pleuropneumoniae Keywords: comparative genomic hybridization
Project description:Viruses can disperse collectively using extracellular vesicles and other types of multi-virion structures. It has been hypothesized that, by increasing the cellular multiplicity of infection, this dispersal mode may favor cooperation among viral genomes. However, the spread of defective variants that function as social cheaters could also be promoted. To better understand the nature of virions present in vesicles, here we examine the genetic diversity harboured by vesicles of coxsackievirus B3 (CVB3), a model enterovirus. Our results confirm that CVB3 vesicles contain multiple infectious particles. However, we also find that virus variants coinfecting a cell typically allocate their progenies into different vesicles, precluding long-term interactions among them. Furthermore, Illumina sequencing indicates that dispersal through vesicles does not increase viral population genetic diversity appreciably. We conclude that vesicles enable the co-dispersal of groups of virions, but that these groups are highly related since they share the same parental genome. This should restrict the evolution of defective viruses, but also makes cooperation among different viral genetic variants unlikely. Our results are in line with a fundamental tenet of social evolution theory, according to which the evolution of cooperation typically requires that the interacting partners are genetically related.
