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Article: Genetic polymorphism as evidence of outbreeding in graptoloids

Special Papers in Palaeontology - No. 13 - Cover Image
Publication: Special Papers in Palaeontology
Number: 13
Thematic Volume: Graptolite studies in honour of O. M. B. Bulman
Edited By: R. B. Rickards, D. E. Jackson and C. P. Hughes
Publication Date: 1974
Page(s): 15 18
Authored By: Adam Urbanek and Valdar Jaanusson
Addition Information

How to Cite

URBANEK, A., JAANUSSON, V. 1974. Genetic polymorphism as evidence of outbreeding in graptoloids. In RICKARDS, R. B., JACKSON, D. E., HUGHES, N. F. (eds.). Graptolite studies in honour of O. M. B. Bulman. Special Papers in Palaeontology13, pp. 15–18.

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Since graptoloids occupied a relatively stable and little differentiated pelagic biotope, numerous instances of genetic polymorphism within their species may be considered as indirect evidence of outbreeding as the mode of their reproduction. Under such conditions genetic polymorphism could be maintained mainly as a result of the heterotic effect, and outcrossing is the only way to provide the requisite heterozygosity.

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