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TIME‐LAPSE ANALYSES OF SEXUAL ISOLATION BETWEEN TWO CLOSELY RELATED MATING GROUPS OF THE CLOSTERIUM EHRENBERG SPECIES COMPLEX (CHLOROPHYTA) 1
Author(s) -
Ichimura Terunobu,
Kasai Fumie
Publication year - 1987
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.1987.tb04201.x
Subject(s) - biology , mating , mating type , reproductive isolation , sexual reproduction , group (periodic table) , strain (injury) , isolation (microbiology) , botany , zoology , evolutionary biology , genetics , gene , microbiology and biotechnology , anatomy , demography , population , chemistry , organic chemistry , sociology
Sexual isolation between Groups A and B of Closterium ehrenbergii, two closely related species, was studied by a multiple‐choice mating method, as well as the nochoice mating method which has been used in previous work on microalgae. Time lapse photomicrographs and the difference in cell shape and size between the two mating groups allowed identification of a given cell in the mixture as either Group A or B, even when certain morphological changes occurred during the several day culture required for sexual induction. When plus and minus mating types of Group A were mixed with those of Group B (multiplechoice mating), no intergroup hybrid zygospores were formed. However, many intragroup zygospores of either Group A or B were formed. When one plus strain of Group A was mixed with one minus strain of Group B or when one plus strain of Group B was mixed with one minus strain of Group A (no‐choice mating), intergroup sexual interactions took place resulting in a small number of hybrid zygospores; however, the process took much longer than intragroup sexual interactions. It was also shown that cell size difference itself hardly affects sexual interactions between haploid and autodiploid strains of Group A. It is suggested that sexual isolation between Groups A and B would be complete in nature, although they may interact sexually in the laboratory.