Production of asexual and sexual offspring in the triploid sexual planarian Dugesia ryukyuensis  

作　　者：Kazuya KOBAYASHI Sachiko ARIOKA Motonori HOSHI Midori MATSUMOTO 

机构地区：[1]Department of Biosciences and Informatics,Keio University,Yokohama,Japan

出　　处：《Integrative Zoology》2009年第3期265-271,共7页整合动物学（英文版）

基　　金：supported in part by a Grant-in-Aid for Scientific Research(Nos.100082 and 16086209)from the Ministry of Science;Culture,Sports and Education,Japan(MH and MM)and from PRESTO,Japan Science and Technology Corporation(KK).

摘　　要：Certain freshwater planarians reproduce asexually as well as sexually,and their chromosomal ploidies include polyploidy,aneuploidy and mixoploidy.Previously,we successfully performed an experiment in which a clonal population produced by asexual reproduction of the Dugesia ryukyuensis(OH strain)switched to the sexual mode of reproduction.Worms of this strain are triploid with a pericentric inversion on Chromosome 4.The worms were switched to sexual reproduction after being fed with sexually mature Bdellocephala brunnea,which is a sexually reproducing species.The resulting sexualized OH strain produced cocoons filled with several eggs.Two putative factors,Mendelian factor(s)and chromosomal control(s),have been proposed as determining the reproductive mode.The present study demonstrated that inbreeding of the resultant sexualized worms produced the following four types of offspring through sexual reproduction:diploid asexual worms,triploid asexual worms,diploid sexual worms and triploid sexual worms.The chromosomal mutation on Chromosome 4 was inherited by these offspring independent of their reproductive mode.These results provide two important pieces of information:(i)the putative genetic factor was not necessarily inherited in a Mendelian fashion;and(ii)the reproductive mode is not regulated by chromosomal changes such as polyploidy or chromosomal mutations.This suggests that asexuality in D.ryukyuensis is regulated by an unknown factor(s)other than a Mendelian factor or a chromosomal control.

关 键 词：ASEXUALITY Dugesia ryukyuensis PLANARIAN POLYPLOIDY reproductive mode. 

分 类 号：Q95[生物学—动物学]