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| Author(s): |
Bruno Udelsmann
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Campinas, SP. |
| Institution: | Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia |
| Defense date: | 2009-11-02 |
| Examining board members: |
Vera Nisaka Solferini;
Louis Bernard Klaczko;
Sergio Russo Matioli;
Luiz Francisco Lembo Duarte
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| Advisor: | Sónia Cristina da Silva Andrade; Vera Nisaka Solferini |
| Abstract | |
In this study, Stramonita haemastoma individuals, a gastropod who inhabits marine rocky shores, were analysed through isozymes electrophoresys and traditional morphometrics. Nine localities in the brazilian shore, extending from Santa Catarina to Rio de Janeiro were sampled. In a preliminary study, a genetic distinction in two different groups was detected. This distinction continues to be found, with evident differentiation in three loci and in minor degree in other loci. After the interpretation of the isozymes data, individuals were adressed as belonging to groups A or B according to their genotypes. To corroborate with this division a genotype atribution test was performed using the software Structure, which resulted in a division 92% similar. The groups A and B were treated independently to obtain the genetic variability and structure parameters. Values were similar to other molluscs whith similar larval development, with moderately high variation and reduced population structure. Group B has higher population structure indicating possible differences in development or dispersal. There were few deviations to Hardy-Weinberg and few linkage disequilibrium, many loci differed in frequencies between populations of distinct groups. Genetic distance was in average 0,338 between populations of distinct genetic groups, a value comparable to other cogeneric species. Between group A populations the distance was in average 0,006 and between group B populations distance was of 0,015 in average. The same individual from the genetic analysis were used for the morphometrics. Eight different shell measures were used. Data was analysed measure by measure and through principal components analysis. The majority of variation was found between sample sites rather than between the groups A and B. From the results of this study it is possible to affirm that the taxonomy of S. haemastoma is not fully understood. The groups A and B have typical characteristics of cogeneric sibling species. More studies are necessary, in broader areas to asses the groups the status of distinct species, by the moment S. haemastoma should be adressed as a species complex. (AU) | |