Fabio Maria Guarino

Satellite DNA (sat-DNA) was previously described as junk and selfish DNA in the cellular economy, without a clear functional role. However, during the last two decades, evidence has been accumulated about the roles of sat-DNA in different cellular functions and its probable involvement in tumorigenesis and adaptation to environmental changes. In molluscs, studies on sat-DNAs have been performed mainly on bivalve species, especially those of economic interest. Conversely, in Gastropoda (which includes about 80% of the currently described molluscs species), studies on sat-DNA have been largely neglected. In this study, we isolated and characterized a sat-DNA, here named PcH-sat, in the limpet Patella caerulea using the restriction enzyme method, particularly HaeIII. Monomeric units of PcH-sat are 179 bp long, AT-rich (58.7%), and with an identity among monomers ranging from 91.6 to 99.8%. Southern blot showed that PcH-sat is conserved in P. depressa and P. ulyssiponensis, while a smeared signal of hybridization was present in the other three investigated limpets (P. ferruginea, P. rustica and P. vulgata). Dot blot showed that PcH-sat represents about 10% of the genome of P. caerulea, 5% of that of P. depressa, and 0.3% of that of P. ulyssiponensis. FISH showed that PcH-sat was mainly localized on pericentromeric regions of chromosome pairs 2 and 4–7 of P. caerulea (2n = 18). A database search showed that PcH-sat contains a large segment (of 118 bp) showing high identity with a homologous trait of the Nin-SINE transposable element (TE) of the patellogastropod Lottia gigantea, supporting the hypothesis that TEs are involved in the rising and tandemization processes of sat-DNAs.

Aim Physiological and metabolic performance are key mediators of the functional response of species to environmental change. Few environments offer such a multifaceted array of stressors as high‐altitude habitats, which differ markedly in temperature, water availability, UV radiation and oxygen pressure compared to low‐altitude habitats. Species that inhabit large altitudinal gradients are thus excellent models to study how organisms respond to environmental variation. Location Tenerife island, Canary Islands archipelago (Spain). Taxon Tenerife lizard ( Gallotia galloti , Lacertidae). Methods We integrated data on age structure, thermal and hydric regulatory behaviour and four metabolic and stress‐related biomarkers for an insular lizard that inhabits an extreme altitudinal range (sea level to 3700 m a.s.l.), to understand how an ectotherms' age, ecophysiology and metabolism can be affected by extreme environmental variation. Results We found marked differences in metabolic stress markers associated with altitude (particularly in the abundance of carbonyl metabolites and relative telomere length), but without a linear pattern along the altitudinal cline. Contrary to expectations, longer telomeres and lower carbonyl content were detected at the highest altitude, suggesting reduced stress in these populations. Evaporative water loss differed between populations but did not follow a linear altitudinal gradient. Lizard age structure or thermal physiological performance did not markedly change across different altitudes. Mixed signals in life‐history and thermal ecology across populations and altitude suggest complex responses to variable conditions across altitude in this species. Main Conclusions Our integrative study of multiple functional traits demonstrated that adaptation to highly divergent environmental conditions in this lizard is potentially linked to an interplay between plasticity and local adaptation variably associated with different functional traits.