Editing Blepharisma (section)

==Reproduction and sexual phenomena==
[[File:Blepharisma diagram.png|thumb|upright=1.5|left| {{center|''Blepharisma'' morphology}}]]

Like all ciliates, ''Blepharisma'' reproduce asexually, by [[fission (biology)|binary fission]], dividing transversally. Fission may occur spontaneously, as part of the [[vegetative reproduction|vegetative]] [[cell cycle]], or it may follow a sexual phenomenon called [[isogamy|conjugation]], a process through which genetic material is exchanged between cells. In conjugation, two organisms come into close contact, and a temporary cytoplasmic bridge forms between them. The [[micronuclei]] of each cell then undergo [[meiosis]], and [[haploid]] micronuclei pass from one individual to the other. This permits the reshuffling of hereditary characteristics, as in other types of [[sexual reproduction]]. Conjugation is immediately followed by binary fission of the two conjugants.<ref>{{cite book | last1 = Lynn | first1 = Denis H. | title = The Ciliated Protozoa: Characterization, Classification and Guide to the Literature | edition = 3 | publisher = Springer | year = 2007 | pages = 23}}</ref>

In ''Blepharisma'', as in some other ciliates, chemical substances called gamones are used to induce conjugation by stimulating interaction between compatible mating partners.<ref>{{cite journal | title = Developmentally and environmentally regulated expression of gamone 1: the trigger molecule for sexual reproduction in ''Blepharisma japonicum'' | journal = Journal of Cell Science | date = 31 May 2005 | last1 = Sugiura| doi = 10.1242/jcs.02359 | first1 = M. | volume = 118 | issue = 12 | pages = 2735–41|display-authors=etal | pmid=15928050| doi-access = free }}</ref>

Although clonal cells of ''Blepharisma'' are sometimes able to conjugate with one another (a phenomenon known as [[selfing]]),<ref name=Miyake>Miyake A. (1981). Cell interaction by gamones in Blepharisma In: Sexual Interactions in Eukaryotic Microbes (O’Day, D.H. editor), pp. 95-129 New York: Academic Press. {{ISBN|978-0124312975}}</ref> conjugation ordinarily involves the interaction of cells of different mating types. In the species ''Blepharisma japonicum'', there are two mating types (I and II), each type excreting a specific pheromone (termed gamone 1 and gamone 2, respectively).<ref name=Miyake /><ref name="pmid20167456">{{cite journal |vauthors=Sugiura M, Shiotani H, Suzaki T, Harumoto T |title=Behavioural changes induced by the conjugation-inducing pheromones, gamone 1 and 2, in the ciliate Blepharisma japonicum |journal=Eur. J. Protistol. |volume=46 |issue=2 |pages=143–9 |year=2010 |pmid=20167456 |doi=10.1016/j.ejop.2010.01.002 }}</ref>  When sexually mature mating-type I cells are moderately starved, they autonomously produce and secrete gamone I.<ref name=Miyake />  Gamone 1 specifically acts on mating-type II cells, transforming them so that they can unite with type I cells, and inducing them to secrete gamone 2.  Gamone 2 then transforms type I cells so that they can unite with type II cells.  Cells that can unite may then undergo conjugation. Conjugation of opposite mating types promotes [[outcrossing]] and the masking of deleterious recessive mutations in the diploid phase of the sexual cycle.<ref name="pmid9299310">{{cite journal |vauthors=Bernstein C, Bernstein H |title=Sexual communication |journal=J. Theor. Biol. |volume=188 |issue=1 |pages=69–78 |year=1997 |pmid=9299310 |doi=10.1006/jtbi.1997.0459 |bibcode=1997JThBi.188...69B }}</ref>

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