DNA extraction and RAPD markers to assess the genetic similarity among Gelidium sesquipedale (Rhodophyta) populations

A simple method developed for genomic DNA isolation from fungus was tested on the red alga, Gelidium sesquipedale (Clem.) Born et Thur., which is commercially exploited for its high sulfated polysaccharide (agar) content. This method is faster, cheaper, and less toxic than conventional phenol/chloroform methods. Random amplified polymorphic DNA (RAPD) amplifications were performed successfully without the necessity of purifying the DNA. RAPD markers were used to investigate the genetic similarity among three natural populations of G. sesquipedale from southern Portugal. Bulked-genomic DNA samples of 15 different individuals were made in each population. These can be conceived of as a sample of the population DNA. Of the 62 primers screened, 41 produced bands and 22 revealed polymorphisms. Genetic similarities among populations were high. Populations that are further away from each other have the lowest similarity coefficients, whereas the intermediate Ingrina population, located on the south coast, showed higher genetic similarity with the Odeceixe population located on the southwest coast, than with the Sao Rafael southern population. This suggests a higher genetic flow between Odeceixe and Ingrina or the result may be a founder effect in the sense that the species has propagated from the east coast to the south coast of Portugal. We conclude that the use of this isolation method with RAPD analysis is appropriate to characterize the genetic variability of this commercial species along its geographical distribution. Large sample sizes can be screened at a relatively low cost. Finding genetic markers for commercial populations of C. sesquipedale may be of industrial interest.

Automatic identification of whole-part relations in Portuguese

Dissertação de Mestrado, Ciências da Linguagem, Faculdade de Ciências Humanas e Sociais, Universidade do Algarve, 2014

Insights into population structure of Diplodus vulgaris along the SW Portuguese coast from otolith elemental signatures

The common two-banded sea bream (Diplodus vulgaris) is an important fish in the marine ecosystems of the NW Atlantic and Mediterranean. In southern Portugal it is a major fishery resource being targeted mainly by the artisanal fleets. Although there is some knowledge of the age, growth and reproductive biology of the species, information about its population structure is scarce and somewhat limited to the Mediterranean Sea. In this study the otolith elemental signatures of 90 specimens of D. vulgaris of the same age group (2+ years) and cohort collected from the important fishery regions of SW Portugal (Sesimbra, Sagres and Faro) have been analysed by inductively coupled plasma mass spectrometry (ICP-MS). Two different methodologies have been applied: solution based analysis of the whole otoliths; representative of the entire life-history prior to capture, and laser ablation analysis of otolith cores; representative of the larval and early post-settlement phase. Whole otolith comparisons utilised Sr/Ca, Ba/Ca, Mn/Ca, Li/Ca and Ni/Ca to demonstrate regional population structure. Classification accuracy rates from linear discriminant function analyses (LDFA) of whole otolith chemistry data were high for each region; Faro - 93%, Sagres - 90% and Sesimbra - 80%. Comparison of the otolith core chemistry utilised Sr/Ca, Ba/Ca, Mn/Ca and Mg/Ca and Zn/Ca. LDFA for the otolith core chemistry also achieved accurate classification for samples from Sesimbra (73%), but there was high overlap of otolith chemistry between samples from Faro and Sagres (47 and 43% classification accuracy respectively). The whole otolith results suggest that D. vulgaris are resident in the regional fishing areas during the juvenile phase. Both the core and whole otolith chemistry data supported separation of the Sesimbra fishery region from the more southern and closely associated Faro and Sagres regions for management purposes. However, while the whole otolith data indicated that the populations at Faro and Sagres likely remained separated in the juvenile stage, the otolith core chemistry data was inconclusive as to whether recruitment to these two areas was derived, or not, from different spawning areas.