No evidence of doubly uniparental inheritance in the brown mussel Perna perna from the RFLP analyses of the mitochondrial 16S rDNA

Abstract

The doubly uniparental mode of inheritance, characteristic of the Mytilidae, consists of an F-type mitochondrial lineage transmitted only through females and an M-type lineage present only in male gonads and therefore transmitted only through males. In this work, we search for evidence of two mitochondrial lineages in Perna perna by studying the same 16S rRNA region that allowed for the discovery of doubly uniparental inheritance in the Mytilus group and in one venerid clam. The region was screened for substitutions using eight restriction enzymes to analyze two kinds of tissues (somatic and gonadal) from 20 males and 20 females from the south of Brazil. A restriction map was constructed after confirming restriction sites with sequence analysis. After amplification with the same primers used in previous studies, a fragment of 517 bp was obtained, which was 10 bp shorter than the one from Mytilus species. No variation was found among individuals or between sexes or kinds of tissue (gonadal and somatic). The absence of variation in this region was confirmed by sequence analysis, and this result left us unable to reject the hypothesis of common maternal mitochondrial inheritance. The 16S rDNA sequence obtained for Perna perna was aligned with twenty-three representative sequences from fifteen mytilid species available in GenBank, and a neighborjoining tree was constructed. The phylogenetic analysis showed all Perna species clustered together in a single branch, which was supported 100% by bootstrap analysis and was more closely related to the branch of the Mytilus group than the other representative genera of the Mytilidae.

Expansion of aquaculture parks and the increasing risk of non‐native species invasions in Brazil

“…; Weber et al . ). Studies show that this mussel may have replaced natural mussel banks in middens on rocks along the coast ranging from Espírito Santo to Rio Grande do Sul states; such impact has also been registered in other areas of the world (Souza et al .…”

“…There is no consensus regarding the origin of the brown mussel (Perna perna), which is considered a cryptogenic species (sensu Carlton 1996). However, strong biogeographical evidence, as well as genetic and paleontological studies, indicates that the species is natural to coastal regions of Africa and that it was introduced to the Brazilian coast between the XVII and XIX centuries, having slave ships as vectors (Souza et al 2003;Weber et al 2009). Studies show that this mussel may have replaced natural mussel banks in middens on rocks along the coast ranging from Esp ırito Santo to Rio Grande do Sul states; such impact has also been registered in other areas of the world (Souza et al 2003;Souza et al 2009).…”

Mitochondrial DNA paradox: sex-specific genetic structure in a marine mussel – despite maternal inheritance and passive dispersal

“…These sex-specific differences are unlikely to be an artifact of two mitochondrial genomes being subject to differential evolutionary constraints sensu 10], because this should have resulted in two copies of COI amplifying with the universal primers used here. Maternally- and paternally-inherited mtDNA genomes are usually highly distinct [ 10 , 16 , 17 ], but the fact that we did not even find genetic structure between males and females (which would be expected if there was a recent masculinisation of female-transmitted mtDNA) suggests that P. perna does not exhibit DUI (see also [ 18 ]) and so can serve as a model for other marine invertebrates in which the sexes are separate and mtDNA is inherited only in the female line.…”

Dispersal barriers and stochastic reproductive success do not explain small-scale genetic structure in a broadcast spawning marine mussel

“…DNA was extracted from foot tissue in the 3 molluscs and from cirri in C. dentatus using the CTAB extraction protocol (Doyle & Doyle 1990). The mitochondrial COI gene was amplified as described previously (Nicastro et al 2008); it is matrilineally inherited in all 4 species (Weber et al 2009, Teske et al 2012). Levels of haplotype and nucleotide diversity were determined in DnaSP v5.10.01 (Librado & Rozas 2009).…”