ANALYSIS OF EVOLUFIONARY RELATIONSHIP BETWEEN ASTASIA LONGA AND EUGLENA GRACILIS BY USING RAPD TECHNIQUE AND CLADISTIC ANALYSIS

Although both Astasia longa and Euglena gracdlis belong to different genera, they share many morphological characters except that A. longa has no chloroplast. In the 1940‘ s, on the basis of the finding that in darkness or upon addition of scrne chemicals, E. gmcilis would fade reversibly or irreversibly, scrne scholars hypothesised that A. longa evolved from E. gracilis by losing chloroplast.The authors‘ use of RAPD and cladistic analyses in a study on the evolutionary relationship between A .longa and E. gmcilis showed that the A. longa ‘ s relationship with E. gmcilis was closer than that with other green euglenoids. This proves the hypothesis that A. longa evolved from E. gmcills is reasonable. The results d this study suggest that saprophytic colorless euglenoids were transformed fromgreen euglenoids by losing their choroplasts.

Analysis of evolutionary relationship betweenAstasia longa andEuglena gracilis by using RAPD Technique and cladistic analysis

Although bothAstasia longa andEuglena gracilis belong to different genera, they share many morphological characters except thatA. longa has no chloroplast. In the 1940's, on the basis of the finding that in darkness or upon addition of some chemicals,E. gracilis would fade reversibly or irreversibly, some scholars hypothesised thatA. longa evolved fromE. gracilis by losing chloroplast. The author's use of RAPD and cladistic analyses in a study on the evolutionary relationship between A. longa andE. gracilis showed that theA. longa's relationship withE. gracilis was closer than that with other green euglenoids. This proves the hypothesis thatA. longa evolved fromE. gracilis is reasonable. The results of this study suggest that saprophytic colorless euglenoids were transformed from green euglenoids by losing their choroplasts. Project 39570063 supported by NSFC and also by Special Fund of CAS.