by Alex Garcia-Cisneros
After a longer period than seems, at least to me, I defended my thesis the last 28th of June. Some members of the ChallenGen project joined the festive day together. The thesis analysed the biology, genetic structure and phylogeography of two starfish species,
Coscinasterias tenuispina and
Echinaster sepositus.
During these years of thesis work, we found a low genetic diversity in both asteroid species, lower than other echinoderms with the same distribution range. However, the reasons differ depending on the species. Low diversity in
E. sepositus can be explained by a recent demographic expansion from few individuals with few alleles, while in
C. tenuispina by the presence of asexual reproduction processes along all its distribution range, even with totally monoclonal populations. Furthermore, our results demonstrate that fissiparity in
C. tenuispina increases with environmental instability. However, well-fed individuals do not lose their potential for sexual reproduction (development of gonads, only males). Finally, a last chapter in
C. tenuispina presents at least one mechanism to avoid or postpone senescence and ensure persistence of clonal populations: telomere elongation.
Although there were nerves, or more precisely, I was extremely nervous, it was a really good festive day.
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| Me, with my son, receiving the PhD certificate from Marta Pascual, the principal investigator at the UB of the Challengen project, who was a member of the thesis tribunal. |
