منابع مشابه
Sex Allocation: Evolution to and from Dioecy
Sex allocation in hermaphrodites should evolve in response to changes in the frequency of unisexuals. As predicted, it has now been demonstrated that hermaphrodites respond to the removal of males from experimental plant populations by increasing their allocation to male function.
متن کاملRepeated evolution of dioecy from monoecy in Siparunaceae (Laurales).
Siparunaceae comprise Glossocalyx with one species in West Africa and Siparuna with 65 species in the neotropics; all have unisexual flowers, and 15 species are monoecious, 50 dioecious. Parsimony and maximum likelihood analyses of combined nuclear ribosomal ITS and chloroplast trnL-trnF intergenic spacer sequences yielded almost identical topologies, which were used to trace the evolution of t...
متن کاملRepeated evolution of dioecy from androdioecy in Acer.
The evolution of breeding systems was studied in the genus Acer, with special attention to the origin of androdioecy and dioecy, using a phylogenetic approach. Parsimony and maximum-likelihood techniques were used to infer the ancestral character state and trends in the evolution of breeding systems. Information on breeding systems was obtained from the literature, and phylogenetic relationship...
متن کاملEVOLUTION OF DIOECY and SEX CHROMOSOMES
Why are there two sexes in certain species, instead of one hermaphroditic sex? Why are Y chromosomes shorter than X chromosomes, but only in certain lineages? I propose that differences between sexes are initially determined by differential methylation in nuclear DNA between females and males, driving Muller’s ratchet. Methylation of promoters suppresses transcription, including loci coding for...
متن کاملThe evolution of gender specialization from dimorphic hermaphroditism: paths from heterodichogamy to gynodioecy and androdioecy.
Several different pathways for the evolution of dioecy from hermaphroditism have been invoked and analyzed. These have largely considered either the spread of male- or female-sterility mutations in a monomorphic hermaphroditic population (i.e., the evolution of gynodioecy or androdioecy, respectively) or the gradual divergence in sex allocation of two classes of individuals, one that becomes in...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Evolution
سال: 1970
ISSN: 0014-3820
DOI: 10.1111/j.1558-5646.1970.tb01820.x