Poster: Genome evolution

Abs # 841: How Diverse are Green Algae? Molecular Evidence from Oklahoma Isolates

Presenter:	Painter, Jacob L, jake@jakepainter.com
Authors	Painter, Jacob L (A)   Buchheim, Julie  (A)   Buchheim, Mark  (A)
Affiliations:	(A): The University of Tulsa

Recent investigations have led to predictions that most eukaryotic microbial species have a cosmopolitan worldwide distribution with low species diversity. The ability to tolerate varied environments coupled with an apparent absence of barriers to dispersal have contributed to the hypothesis of global distribution and low diversity. Pan-global distribution of eukaryotic microbes is predicated on the broad validity of a morphological species concept. However, the use of a "morphospecies" concept for identifying green microalgae, where cryptic species abound, may underestimate the actual genetic diversity. The research presented here was designed to begin addressing these concerns by collecting and characterizing (by comparative 18S rDNA analysis) green microalgae isolated from different freshwater sites in the Tulsa, Oklahoma (USA) area. Results from this study revealed substantial molecular differences among the collected algal samples, with many 18S rDNA sequences that are new to science. Local diversity among Scenedesmus and Mychonastes isolates is particularly pronounced. The unexpected molecular diversity appears to be incongruent with hypotheses of low species diversity. Furthermore, these results fail to eliminate endemism as an explanation for the distribution of green microalgae.