Tesis Doctorado
Latitudinal variatión in the genetic architecture and gene expressión of physiólogical traits in the land snail cornu aspersum
Author
Gaitán-Espitia, Juan Diego
Institutions
Abstract
Environmental variation across geographical gradients is a key driver in the evolution of biodiversity, giving rise to genetic and phenotypic variation within species, and affecting survival and reproduction of the organisms. Such variation has been well documented acrosslatitudinal gradients, in which climatic conditions are paramount factors affecting the rate of most biological processes through changes in the rates of physiological and biochemicalprocesses. For instance, lower mean temperatures, extreme seasonality and shorter growing seasons at higher latitudes would be expected to cause a decline in the biological perfomance ofectotherms. However, if a reduction in the rates of biological processes involves a reduction in fitness, then organisms may evolve compensatory responses for the constraints imposed by highlatitude habitats. In principie, two alternative models could explain the evolution of a latitudinal compensation in ectotherms. One model is through local thermal adaptation, which predicts that organisms from high latitudes should function better at low temperatures inrelation to their counterparts from lower latitudes. The alternative model is through countergradient variation, which predicts that organisms compensate for the climatic constraints at high latitudes by increasing performance, growth, and fecundity relative to theirlower-latitude counterparts when compared ata common temperature. Under this context, this thesis presents the findings from a body of research that broadly encompassed the examinationof the intraspecific variation and adaptive differentiation of physiological traits in ectotherms using as biological model the land snail Cornu aspersum. The integration of different approachesallowed the study of not only the phenotypic variation in natural populations but also the genetic basis that underlie this variation. The results indicate that populations of C. aspersumacross a latitudinal gradient in Chile, adopt a mixed strategy of latitudinal compensation through thermal adaptation and countergradient variation in performance and growth rates.However, it was not found evidences of phenotypic compensations in the maintenance metabolism, which was also evidenced at the genomic and transcriptomic level among populations of the land snail. PFCHA-Becas Doctorado en Ciencias Mención Sistemáatica y Ecología 157p. PFCHA-Becas TERMINADA