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GENOTYPIC VARIATION AND ALTERNATING DNA LEVELS AT CONSTANT CHROMOSOME NUMBERS IN THE LIFE HISTORY OF THE BROWN ALGA HAPLOSPORA GLOBOSA (TILOPTERIDALES) 1
Author(s) -
Kuhlenkamp Ralph,
Müller Dieter G.,
Whittick Alan
Publication year - 1993
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.0022-3646.1993.00377.x
Subject(s) - sporophyte , biology , gametophyte , parthenogenesis , ploidy , spore , chromosome , population , botany , meiosis , zoology , genetics , embryo , gene , pollen , demography , sociology
The brown algal order Tilopteridales contains three monospecific genera with reduced life histories, Which are assumed to have been derived form ancestors with oogamous reproduction and alternation of generations. The Newfoundland population of Haplospora globosa Kjellman still shows an alternation of gametophytes and sporophytes, but the chromosome Numbers remain equal because of parthenogenesis and apomeiosis, However, DNA fluorometry showed that the DNA level is twice as high in the Sporophytes as in the gametophytes, The DNA variation at constant chromosome numbers is presumably due to endomitosis combined with a law degree of polyteny. A genotypic variant of Haplospora is represented by the population at Helgoland (F.R.G.) where only sporophytes exist, Spores develop into sporophytes instead of gametophytes, and the plants have reduced chromosome number but the same DNA level as the Newfoundland sporophytes