Mutations as molecular tools : The metabolic-rate dependent molecular clock and DNA barcoding of allied species

• Main Author: Brustle, Lena
• Other Authors: Kallersjo, Mari, University of Helsinki, Faculty of Biosciences, Department of Biological and Environmental Sciences, Finnish Museum of Natural History, Helsingin yliopisto, biotieteellinen tiedekunta, bio- ja ympäristötieteiden laitos, Helsingfors universitet, biovetenskapliga fakulteten, institutionen för bio- och miljövetenskaper, Muona, Jyrki
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Helsingin yliopisto 2010
• Subjects: evoluutiobiologia; karelia*
• Online Access: http://hdl.handle.net/10138/22437

Mutation and recombination are the fundamental processes leading to genetic variation in natural populations. This variation forms the raw material for evolution through natural selection and drift. Therefore, studying mutation rates may reveal information about evolutionary histories as well as phylogenetic interrelationships of organisms. In this thesis two molecular tools, DNA barcoding and the molecular clock were examined. In the first part, the efficiency of mutations to delineate closely related species was tested and the implications for conservation practices were assessed. The second part investigated the proposition that a constant mutation rate exists within invertebrates, in form of a metabolic-rate dependent molecular clock, which can be applied to accurately date speciation events. DNA barcoding aspires to be an efficient technique to not only distinguish between species but also reveal population-level variation solely relying on mutations found on a short stretch of a single gene. In this thesis barcoding was applied to discriminate between Hylochares populations from Russian Karelia and new Hylochares findings from the greater Helsinki region in Finland. Although barcoding failed to delineate the two reproductively isolated groups, their distinct morphological features and differing life-history traits led to their classification as two closely related, although separate species. The lack of genetic differentiation appears to be due to a recent divergence event not yet reflected in the beetles molecular make-up. Thus, the Russian Hylochares was described as a new species. The Finnish species, previously considered as locally extinct, was recognized as endangered. Even if, due to their identical genetic make-up, the populations had been regarded as conspecific, conservation strategies based on prior knowledge from Russia would not have guaranteed the survival of the Finnish beetle. Therefore, new conservation actions based on detailed studies of the biology and life-history of the Finnish ...