Mitochondrial DNA analyses of Donax trunculus (Mollusca: Bivalvia) population structure in the Iberian Peninsula, a bivalve with high commercial importance

Abstract

1. The wedge clam, Donax trunculus (Linnaeus, 1758), is an ecologically and economically important species found in the warm waters of the Atlantic and Mediterranean areas. Donax trunculus has been suffering from a severe population decline in some wild stocks of the Iberian Peninsula, and genetic monitoring of wild populations can provide valuable information to support conservation measures and management policies.2. In this study, mitochondrial 16S rDNA (16S) and cytochrome b (Cytb) gene variation was examined at 18 localities across the Iberian Peninsula to test whether the patterns of genetic diversity, population structure, and demographic inferences previously deduced by using microsatellites are supported by these molecular markers. 3. Samples (N = 557) were collected from 18 localities of the Iberian Peninsula and attention was paid to the north-western Atlantic area, where wild stocks have diminished greatly. Analysis of molecular variance, fixation index ( F ST ), and demographic inferences were estimated based on mitochondrial DNA. Since D. trunculus shows doubly uniparental inheritance, both types of mitochondrial DNA (F and M) were analysed. 4. A high level of genetic diversity was detected using the haplotype diversity dataset, showing different geographic patterns. 5. F ST values for the M type revealed significant differentiation between populations on both sides of the Almeria-Oran front, and between the locality from the Alboran Sea (FU) and localities from the Atlantic Ocean. However, the F type did not detect the differentiation of FU. This makes the M genome sequences more suitable for investigating genetic structure of D. trunculus populations. 6. Management and recovering strategies of this important resource should consider the genetic structure observed. 7. Several strategies for conservation and management of this commercial and ecologically important bivalve are proposed. * Both authors contributed equally to this work.

Sequence characterization of the 5S ribosomal DNA and the internal transcribed spacer (ITS) region in four European Donax species (Bivalvia: Donacidae)

“…Overall, 5S and ITS sequences show higher values of nucleotide diversity ( D. trunculus : 0.019–0.022; D. vittatus : 0.022–0.056) than other nuclear (18S, 28S and H3) and mitochondrial (16S and Cytb) markers in the same Donax species ( D. trunculus : ~0.005, [ 23 ]; D. vittatus : 0–0.007, [ 23 ]), possibly due to the high variability of NTS and ITS, even though 5S and 5.8S genes present high conservation degree through species [ 14 , 38 ], but also they are of smaller length. These results are in line with other marine species such as Hexaplex trunculus [ 33 ] where 5S was more variable than mitochondrial sequences (12S, 16S and COI).…”

“…In addition, Theologidis et al [ 96 ] have studied the mode of inheritance of mitochondrial DNA. Recently, microsatellite markers have also been developed [ 64 , 82 ] and population genetic analyses based on this type of molecular markers [ 57 , 63 , 82 ] and mitochondrial markers [ 23 ] have been carried out.…”

Polylactic acid synthesis, biodegradability, conversion to microplastics and toxicity: a review

“…Mollusks are a diverse group of filter feeders which can be found in a variety of aquatic habitats. They provide ecological services to a number of organisms ranging from habitat to food (Fernández-Pérez et al 2018). Being filter feeders, mollusks can accumulate and transfer microplastics to higher trophic levels, which will have detrimental effects on their consumers including humans.…”

Impacts of Microplastics on Marine Organisms and in Human Health

“…They are a diverse group that can be found in a variety of aquatic habitats settings. They play a crucial role in ecosystem engineering, reshaping aquatic bottom conditions while also providing habitat, security, and food for a variety of other taxa (Fernández Pérez et al 2018).…”