Verrier, E. | Search bioRxiv

bioRxiv2023

Unraveling human, rodent and snake Kolmioviridae replication to anticipate cross-species transmission

The recent discovery of Hepatitis D (HDV)-like viruses across a wide range of taxa led to the establishment of the Kolmioviridae family. Recent studies suggest that kolmiovirids can be satellites of viruses other than Hepatitis B virus (HBV), challenging the strict HBV/HDV-association dogma. Studying whether kolmiovirids are able to replicate in any animal cell they enter is essential to assess their zoonotic potential. Here, we compared replication of three kolmiovirids: HDV, rodent (RDeV) and snake deltavirus (SDeV) in vitro and in vivo. We show that SDeV has the narrowest and RDeV the broadest host cell range. High resolution imaging of infected cells revealed nuclear viral hubs with a peculiar RNA-protein organization. Finally, in vivo hydrodynamic delivery of infectious clones showed that both HDV and RDeV, but not SDeV, efficiently replicate in mouse liver, forming massive nuclear viral hubs. Our comparative analysis lays the foundation for the discovery of specific host factors controlling Kolmioviridae host-shifting.

microbiology↗

bioRxiv2023

Reintroducing genetic diversity in populations from cryopreserved material: The case of Abondance, a French local dairy cattle breed

BackgroundGenetic diversity is a necessary condition for populations to evolve under adaptation, selection or both. However, genetic diversity is often threatened, in particular in domestic animal populations where artificial selection, genetic drift and inbreeding are strong. In this context, cryopreserved genetic resources appear as a promising option to reintroduce lost variants and to limit inbreeding. However, while more common in plant breeding, the use of cryopreserved resources is less documented in animals due to a longer generation interval making it difficult to fill the performance gap due to continuous selection. Thus, this study investigates one of the only concrete cases presenting the results of the use of cryopreserved semen of a bull born in 1977 and belonging to a disappeared lineage, into the breeding scheme of a French local dairy cattle breed, the Abondance breed, more than 20 years later. ResultsWe found that this re-used bull was very original relative to the current population and thus allowed to restore genetic diversity lost over time. The expected negative gap in milk production due to continuous selection has been absorbed in a few years by preferential mating with elite cows. Moreover, the re-use of this old bull did not increase the level of inbreeding, it even tended to reduce it by avoiding mating with relatives. Finally, the reintroduction of an old bull in the breeding scheme allowed for increased performance for reproductive abilities, a trait that was less subject to selection in the past. ConclusionsThe use of cryopreserved material was efficient to manage the genetic diversity of an animal population, by mitigating the effects of both inbreeding and strong selection. However, attention should be paid toward mating in order to limit the disadvantages associated with the provision of genetic originality, notably a discrepancy in the breeding values for selected traits or an increase in inbreeding. Therefore, a careful characterization of the genetic resources available in cryobanks could help to ensure the sustainable management of populations and of local or small ones in particular. These results could also be transferred to the conservation of wild populations.

genetics↗