Genetic population structure and connectivity of the mud creeper Terebralia palustris (Linnaeus, 1767) in Kenya, Tanzania and Madagascar
Ratsimbazafy, H. (2012). Genetic population structure and connectivity of the mud creeper Terebralia palustris (Linnaeus, 1767) in Kenya, Tanzania and Madagascar. MSc Thesis. VUB: Brussel. 17 pp.
|
| Beschikbaar in | Auteur |
|
Documenttype: Doctoraat/Thesis/Eindwerk
|
| Trefwoorden |
Terebralia palustris (Linnaeus, 1767) [WoRMS]
ISW, West Indian Ocean [Marine Regions]
Marien/Kust |
| Author keywords |
Terebralia palustris; population genetic; connectivity; gene flow; Western Indian Ocean |
| Abstract |
Terebralia palustris (Potamididae: Gastropoda), the largest prosobranch of the muddy substrates in mangrove forests is widespread in the Indian Ocean as well as the Indo-Pacific region. The duration of the larval phase remains unknown but the estimate for other prosobranch suggests a possible larval stage of two months which could enhance a high potential of dispersal. Mitochondrial cytochrome c oxidase subunit I (COI) gene was used to investigate 177 individuals from 10 sites over Kenya, Tanzania and Madagascar by means of DNA sequencing. 624 base pairs were examined and 26 haplotypes were identified. Two haplotypes were shared among all the populations and only three mutational steps were found as a maximum genetic distance. Genetic diversity as well as historical demography analysis indicates population expansion. Isolation- by- distance analysis revealed no significant increase in genetic diversity with increasing geographic distance. Analysis of molecular variance (AMOVA) revealed no significant genetic differentiation among populations. These results indicate high gene flow as well as high level of connectivity between the Kenyan and Tanzanian part of the Eastern African coast and Western Malagasy coast for Terebralia palustris even within large geographic distances reaching more than one thousand kilometres. Geological history is more likely the origin of this population expansion. And the oceanography acting more likely as drift factor for the larvae combined with the occurrence of Islands which could act as stepping stones as well as the possibility that Terebralia palustris could have a long duration of larval phase are potential factors driving to this panmictic population in the region. |
|
