Caracterización de la estructura genética poblacional de fasciola hepática mediante marcadores alozímicos y microsatélites

  1. Vázquez Prieto, Severo
unter der Leitung von:
  1. Esperanza Paniagua Crespo Doktormutter
  2. Román Vilas Peteiro Co-Doktorvater

Universität der Verteidigung: Universidade de Santiago de Compostela

Fecha de defensa: 05 von Juli von 2012

Gericht:
  1. Florencio Martínez Ubeira Präsident
  2. María Elvira Ares Mazás Sekretärin
  3. Marta González Warleta Vocal
  4. Mercedes Mezo Vocal
  5. María Dolores Bargues Vocal
Fachbereiche:
  1. Departamento de Microbioloxía e Parasitoloxía

Art: Dissertation

Zusammenfassung

Twelve polymorphic genetic markers, eight allozymic loci and four microsatellites, were used to characterize 20 infrapopulations of Fasciola hepatica (all flukes from 10 individual cattle and 10 sheep) from 11 farms in Northwest Spain. Results suggest different patterns of population genetic structure depending on the host species. Individuals identified as clones were much more frequent in sheep. The common presence of clones and its nonrandom occurrence among individual hosts suggests clumped transmission of liver flukes in sheep. After reducing significant repeated multilocus genotypes to one unique copy within infrapopulations, results show relatively high levels of gene diversity within infrapopulations from cattle and sheep (0.411 and 0.360 on average, respectively). However, parasites of sheep appear to show significantly more structured variation at the infrapopulation level (Standardized FST = 0.087 and 0.170 for parasites of cattle and sheep, respectively). Compared to the parasites from cattle, results suggest that populations from sheep show lower levels of gene flow, higher degree of aggregate transmission, higher probability of mating within clones, and lower parasitic load. These differences have implications for the evolution of anthelmintic resistance because they affect the effective population size and the degree of inbreeding. The development and rapid spread of resistance seems likely in the parasites of cattle because populations from the study area are characterized by high gene flow. However, results also suggest that the efficient selection of a new recessive advantageous mutation would be favored in parasites of sheep due to a greater potential for inbreeding.