Insights on the potential role of doubly uniparental inheritance of mitochondria in genetic structure and fitness of the marine bivalve Macoma balthica
Résumé
Mito-nuclear genetic incompatibilities (MNI) can contribute to reproductive isolation. The remarkable system of doubly uniparental inheritance (DUI) of bivalves is an attractive model to study the role of MNI in maintaining reproductive isolation because males carry two highly divergent mitochondrial genomes. We look for MNIs in populations of Macoma balthica, a littoral species characterized by DUI and hybrid zones that may be conducive to MNIs. We inventoried interacting mitochondrial and nuclear genes using reference transcriptomes and used these data to build a custom capture bait set. We applied the latter to 254 male individuals (bearing both male and female mitotypes) across the hybrid zone spanning from Finistère to Cotentin along the seashore of Western France. We will look for statistical signatures of MNIs for male- and female-specific mitochondrial function pathways. Genomic data will be coupled to an ecophysiological assessment of mitochondrial function across the hybrid zone. Enzyme activities involved in bioenergetics (Citrate synthase and ATPase) will be assessed in and out of the hybrid zone to investigate the effect of MNI on individual energetic metabolism. We hope these data will help shed light on the potential interaction between DUI and MNIs in shaping patterns of genetic structure and local adaptation of the baltic tellin.