Symbiotic genomic acquisition and metazoan phylogeny
Scudo, F. M.
IGBE-CNR, Via Abbiategrasso 207, I-27100 Pavia, Italy
Barnacles' phylogeny was Darwin's most time consuming and least conclusive entreprise mainly because their cement is not found in any other animal (if it were endogenous, and shared with other crustaceans, it would be a most illuminating feature). If the apparent symbiotic origin of this unique adaptation could be somehow traced - even just at the molecular level - inferring its
convergence effects could allow to identify the three crustacean stocks from which they orginated. These appear being quite different through other features such as the peculiar eye-like attachment structure of the lepadidae. On the other hand hyrudinean key traits have been well identified at the molecular level as due to extant or pregressed bacterial symbioses. Slow progress in ascertaining the phylogeny of these symbioses would help confirming their apparent diphyletic orgin, allowing to reasonably sort out their parental stocks. Also the two pogonophoran subphyla quite likely originated from two anellid stocks through symbiotic convergence, unfortunately only well known on the tube worms side. At a different level, the viral symbioses which most likely gave rise to mobile, repetitive elements look even more promising, as for the alu so widespread in the primates and its monomeric counterpart in the rodents. As inferred from their flanking regions, times of origin of alu-like elements are close to the radiation of modern mammals as inferred from scattered, still controversial paleontological data. Timings ascertained in this way seem more reliable than those from base changes in third position, that are more strongly constrained by function and whose rates appear being more variable among lineages.
| LOCATION |
DATE |
TIME |
| Lecture Hall II |
Monday, April 6 |
10:40 am |