Biology subjects

Lecompte, E.

Publications and source records attributed to Lecompte, E..

4 recordsLinked to original sources

bioRxiv2026

Wolbachia facilitates the reproduction of a parthenogenetic ladybug

Wolbachia is a bacterial endosymbiont that is primarily transmitted from mother to offspring. To increase their transmission, some strains manipulate their hosts reproduction to favor female offspring, such as by inducing parthenogenesis. Here, we assess whether Wolbachia induces parthenogenesis in recently discovered parthenogenetic populations of the ladybug Nephus voeltzkowi by treating females with an antibiotic. Females from sexual populations, which we show are not infected by Wolbachia, serve as a control. Our results demonstrate that the treatment decreases Wolbachia load, subsequently reducing egg production and development among parthenogenetic females, while having no effect on sexual females. Wolbachia load and reproduction then rebound when the treatment is removed. This suggests that the Wolbachia infection is necessary for successful reproduction in the parthenogenetic females, and it may play a two-part role by facilitating egg laying and late embryo development. The cooccurrence of Wolbachia infection and parthenogenesis in N. voeltzkowi, as well as Wolbachias manipulation of host reproduction makes this a likely candidate of Wolbachia-induced parthenogenesis outside of haplo-diploids. Understanding how Wolbachia can impact diverse insect reproductive systems can shed a light on the extent in which these bacteria can manipulate hosts for their own gain.

evolutionary biology↗

bioRxiv2023

Genetic tracing of the white-bellied pangolins (Phataginus tricuspis) trade in western central Africa

African pangolins are intensively harvested to feed illegal trade networks. We focused on the conservation genetics of the most trafficked African species, the white-bellied pangolin (WBP; Phataginus tricuspis), through the genotyping of 562 individuals from reference populations and urban bushmeat markets in a vibrant trade hub from western Central Africa. Across Cameroon, Equatorial Guinea and northern Gabon, we observed a lack of genetic differentiation and a signature of isolation-by-distance possibly due to unsuspected dispersal capacities involving a Wahlund effect. Despite a higher level of genetic diversity compared to western Africa, we detected a 74-83% decline in the effective population size of WBP during the Middle Holocene. Private allele frequency tracing approach indicated up to 600 km sourcing distance by large urban markets from Cameroon, involving transnational trade activities. The 20 microsatellites markers used in this study provided the necessary power to distinguish among all WBP individuals and should be considered a valuable resource for future forensic applications. Because lineage admixture was detected in the study area, we recommend a multi- locus approach for tracing the WBP trade. The Yaounde market was a major recruiter of genetic diversity in the region, and should receive urgent conservation action to mitigate the pangolin trade.

genetics↗

bioRxiv2021

The antique genetic plight of the Mediterranean monk seal (Monachus monachus)

Disentangling the impact of Late Quaternary climate change from human activities can have crucial implications on the conservation of endangered species. We investigated the population genetics and demography of the Mediterranean monk seal (Monachus monachus), one of the worlds most endangered marine mammals, through an unprecedented dataset encompassing historical (extinct) and extant populations from the eastern North Atlantic to the entire Mediterranean Basin. We show that Cabo Blanco (Western Sahara/Mauritania), Madeira, Western Mediterranean (historical range), and Eastern Mediterranean regions segregate into four populations. This structure is likely the consequence of recent drift, combined with long-term isolation by distance (R2 = 0.7), resulting from prevailing short-distance (< 500 km) and infrequent long-distance dispersal (< 1,500 km). All populations (Madeira especially), show high levels of inbreeding and low levels of genetic diversity, seemingly declining since historical time, but surprisingly not being impacted by the 1997 massive die-off in Cabo Blanco. Approximate Bayesian Computation analyses support scenarios combining local extinctions and a major effective population size decline in all populations during Antiquity. Our results suggest that the early densification of human populations around the Mediterranean Basin coupled with the development of seafaring techniques were the main drivers of the decline of Mediterranean monk seals.

genetics↗

bioRxiv2018

Contrasted sex chromosome evolution in primates with and without sexual dimorphism

AO_SCPLOWBSTRACTC_SCPLOWSex chromosomes are typically comprised of a non-recombining region and a recombining pseudoautosomal region. Accurately quantifying the relative size of these regions is critical for sex chromosome biology both from a functional (i.e. number of sex-linked genes) and evolutionary perspective (i.e. extent of Y degeneration and X-Y heteromorphy). The evolution of the pseudoautosomal boundary (PAB) - the limit between the recombining and the non-recombining regions of the sex chromosomes - is well documented in haplorrhines (apes and monkeys) but not in strepsirrhines (lemurs and lorises), which represent almost 30% of all primates. Here we studied the PAB of seven species representing the main strepsirrhine lineages by sequencing a male and a female genome in each species and using sex differences in coverage to identify the PAB. We found that during primate evolution, the PAB has remained unchanged in strepsirrhines whereas several recombination suppression events moved the PAB and shortened the pseudoautosomal region in haplorrhines. Strepsirrhines are well known to have much lower sexual dimorphism than haplorrhines. We suggest that mutations with antagonistic effects between males and females have driven recombination suppression and PAB evolution in haplorrhines. Our work supports the view that sexually antagonistic mutations have influenced the evolution of sex chromosomes in primates.

evolutionary biology↗