Inheritance pattern of microsatellite loci in the polyploid Adriatic sturgeon (Acipenser naccarii)

The Adriatic sturgeon is a highly endangered tetraploid species whose conservation depends up ex-situ management of the remnant genetic variability. Understanding whether the species follows a tetrasomic or a disomic inheritance pattern is of primary importance to set up a parental allocation procedure and to establish a long-term breeding plan. Moreover, comprehending the inheritance modality can strongly contribute to understanding the origin of tetraploidy in this species. For this purpose, microsatellite inheritance patterns were analyzed in 7 complete families and at 7 loci for a total of 12 family/locus combinations. For each available family, a preliminary selection of loci was performed, in order to avoid ambiguities due to allele dosage, null alleles or interference between parental contributions. Results allowed to unambiguously reject a strict disomic inheritance pattern and to suggest tetrasomy as the more likely model. Accordingly, parental chromosomes can be expected to pair in the gametes in all possible combinations, though a certain degree of preferential pairing could not be excluded for the limited statistical power reached. This study represents the first investigation of the inheritance pattern in the Adriatic sturgeon and provides relevant information for the correct management of its residual genetic diversity.

► Tetrasomic versus disomic inheritance pattern in a polyploid sturgeon species.
► A preliminary selection of microsatellite loci allowed to follow allele inheritance.
► Pure disomic inheritance pattern was significantly rejected.
► All parental chromosome combination were observed.