The composition of parasite communities in two cyprinid species in southern France – native and threatened Parachondrostoma toxostoma and introduced Chondrostoma nasus – was investigated. In sympatry, these two species form two hybrid zones in the Durance and Ardeche Rivers. Due to their different feeding preference and habitat positions in allopatry, we supposed a difference in parasite communities between fish species. We expected more similar parasite communities in sympatric zones associated with habitat overlap (facilitating the transmission of ectoparasites) and similar feeding (more generalist behaviour when compared to allopatry, facilitating the transmission of endoparasites) in both fish species. Finally, we investigated whether P. toxostoma x C. nasus hybrids are less parasitized then parental species.

Hybridization is a common phenomenon in fish and is considered to be a major source of diversification. Deciphering the remoulding of genomic regions and phenotypes in zones where hybrid specimens occur is of particular interest to elucidate the emergence of evolutionary novelties. This approach is particularly challenging because the first step of hybridization seems to be the most important stage in the emergence of hybrid lineages. However, the signal can be significantly altered after only a few generations. We studied 41 microsatellites and partial cytochrome b gene sequences in 970 specimens belonging to two fish species (Chondrostoma nasus and Parachondrostoma toxostoma) in allopatric/parapatric zones, hybrids between them in a natural sympatric zone: the Ardèche basin. We showed that the genomic architecture in hybrids presented pattern heterogeneity of selection for the different loci. Indeed, the upstream part of the river (Rosières and Labeaume) presented an overdominant fitness of heterozygotes (12.20%) corresponding to a genomic compatibility, and underselection was observed for 4.88%-7.32% of the loci tested indicating a genomic incompatibility. Moreover the upstream station (Rosières) presented a positive selection of invasive C. nasus homozygotes (17.07% to 21.95%) indicating that hybridization may increase the fitness of admixed individuals. We showed that hybrid morphology (body shape based on 21 landmarks) correlated with genomic dilution indicating a species fingerprint. However, we demonstrated that the hybrid morphology was not a linear modification between the two parental species but a trade-off between several correlated traits. Hybrid specimens present a mosaic of genomic combination, showing regions with genomic compatibility and others with genomic incompatibility between the two species. Positive selection (invasive advantage ranging from 9.76% to 21.95% of the loci) was evidenced in the upstream part of the Ardèche indicating that environmental selection makes a substantial contribution. Although the presence of a dam is known to impose heterogeneous hybrid zones between these two species, we demonstrated in this study that a natural environment can also generate a hybrid zone with a large number (and diversity) of hybrids. The combination of the two genomes in the hybrids results in complex ontogenetic trajectories (with different morphological traits evolving at different rates) that correspond to novel developmental pathways.

After causing mass disasters that claimed the lives of tens of thousands of soldiers from countries around the world, the two Great Wars left some of them lost and missing. In France, these corpses reside in a legal vagueness where they belong neither to forensic anthropology nor archeology. Nevertheless, the process of identification and determining the cause of death requires the use of modern forensic anthropology by applying biological profiling and DNA analysis. New genomic methods also provide insight into the health statuses of these military populations, providing new perspectives on these periods of humanitarian crisis.

Red cell polymorphisms can provide evidence of human migration and adaptation patterns. In Eurasia, the distribution of Diego blood group system polymorphisms remains unaddressed. To shed light on the dispersal of the Di^a antigen, we performed analyses of correlations between the frequencies of DI*01 allele, C2-M217 and C2-M401 Y-chromosome haplotypes ascribed as being of Mongolian-origin and language affiliations, in 75 Eurasian populations including DI*01 frequency data from the HGDP-CEPH panel. We revealed that DI*01 reaches its highest frequency in Mongolia, Turkmenistan and Kyrgyzstan, expanding southward and westward across Asia with Altaic-speaking nomadic carriers of C2-M217, and even more precisely C2-M401, from their homeland presumably in Mongolia, between the third century BCE and the thirteenth century CE. The present study has highlighted the gene-culture co-migration with the demographic movements that occurred during the past two millennia in Central and East Asia. Additionally, this work contributes to a better understanding of the distribution of immunogenic erythrocyte polymorphisms with a view to improve transfusion safety.

Cet article a été suscité à partir d’un double constat. Un constat factuel qui montre que lors de la Covid 19, de façon récurrente et sous des expressions diverses, les épidémies de peste ont été convoquées, à divers titres. Un constat anthropologique qui met en évidence non pas les similitudes historiques et épidémiologiques des crises épidémiques (Peste-Covid 19), ni une forme quelconque d’analogie possible, mais bien le dessin de la peste en filigrane de la Covid 19, au prisme de certains invariants anthropologiques : le rapport à la mort et son cortège de peurs, en temps de crise, liées à l’alimentation, à la contagion ; les rituels engendrés, de formes anciennes ou nouvelles ; les règles d’exception liées à la gestion de crise sanitaire. Il s’agit, par- delà les échos, les récurrences, de mettre à jour ces invariants structurant le social.