Evolutionary Significance of Polyploidy in the Pteridophyta

Polyploidy occurs in the heterosporous and homosporous Pteridophyta, but with a much higher frequency in the latter. Ninety-six percent of the homosporous Pteridophyta show a gametic chromosome number greater than 27, whereas 90 percent of the heterosporous ones possess a gametic chromosome number l...

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Bibliographic Details
Published in:Science (American Association for the Advancement of Science) 1966-07, Vol.153 (3733), p.305-307
Main Authors: Klekowski, Edward J., Baker, Herbert G.
Format: Article
Language:English
Subjects:
Ferns
Gametophytes
Male animals
Mammary glands
Ploidies
Polyploidy
Rats
RNA
Sporophytes
True ferns
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Summary:Polyploidy occurs in the heterosporous and homosporous Pteridophyta, but with a much higher frequency in the latter. Ninety-six percent of the homosporous Pteridophyta show a gametic chromosome number greater than 27, whereas 90 percent of the heterosporous ones possess a gametic chromosome number less than 28. Ultrafrequent establishment of polyploidy in the homosporous Pteridophyta appears to be necessary to create and maintain genetic variation in the face of the homozygotizing effects of habitual self-fertilization in the monoecious gametophytes of these plants.
ISSN:0036-8075
1095-9203
DOI:10.1126/science.153.3733.305