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Scallops (family Pectinidae) comprise species of high commercial value, supporting both commercial fisheries and mariculture activities. Accurate and reliable molecular methods for the species level identification are of outstanding utility for taxonomic and food authentication surveys. The mitochondrial 16S rRNA gene has been used to design species-specific primers for identification of different bivalve species. However, the low interspecific variability at the 3′ end of this gene has limited its utility and only few scallop species have been assessed. In this study, we used the high variable 5′ end of the 16S gene to develop a novel decaplex PCR assay that enabled a fast and accurate identification of eight commercially important scallop species in a single PCR reaction. A total of 285 individuals including fresh and manufactured samples from eight different processed presentations from 11 different scallop species were collected representing diverse locations around the world. Our assay accurately identified all the analysed samples at the species level. Furthermore, to enhance the utility of our assay, the PCR product amplified by the family specific primer set that was utilized as positive control was also used for the identification of unknown (non-target) scallop species by DNA sequencing analysis. In its present form, our multiplex PCR method can be of great utility for different types of studies involving scallop species and for research institutes and governmental agencies that regulate seafood authentication around the world.

Scallops (Bivalvia, Pectinidae) are among the most valuable source of marine food. With about 350 extant species distributed worldwide and a total global production comprising 18 species, the development of proper species-level identification assays is imperative. DNA barcoding has proven to be a useful tool in species identification. A partial region at the 5' end of the mitochondrial cytochrome c oxidase subunit I (COI) gene, known as the "Folmer region," was proposed as the most suitable DNA barcoding marker. However, Folmer primers have failed to amplify polymerase chain reaction (PCR) products in different organisms, including scallops. Searching for an alternative barcoding gene region, we analyzed the complete mitochondrial 16S rRNA gene in 15 scallop species. We found that the interspecific variation at the 5' end is twice as high as that at the 3' end. Based on that evidence, we designed a novel Pectinidae family-specific primer set, aiming to amplify a partial region at the 5' end of the 16S rRNA gene, and tested its suitability as a barcoding tool. A neighbor-joining analysis identified correctly 100 % of the scallop specimens analyzed, with high bootstrap support. Our new primers are well suited for DNA barcoding analysis and may contribute to scallop food industry surveys, as well as routine taxonomic surveys.

In recent years much attention has been paid to the effect on wages of skill-biased technology, especially the use of computers. Although empirical studies have shown a positive relationship between computer-use and earnings, doubts have been cast on whether this is a causal relationship or merely represents unobserved other factors, which are themselves positively linked to computer usage. In this paper we provide evidence that computers themselves raise wages. Although their impact on wages falls as other controls are included in the regression, it still remains significant whilst the effect of another proxy for unobserved factors becomes insignificant. Furthermore, improvements in computer use have an additional impact on earnings, supporting the productivity interpretatio