Results 131 to 140 of about 2,154 (173)
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Biphasic Retention of One-Trial Learning in a Clonal Fish (Poecilia formosa)
Nature New Biology, 1972Most species used for behavioural studies are bisexual. Sexual dimorphism determines genotypic diversity and behavioural variation within a species. The relative contribution of a genome to a specific behaviour is for the most part indiscernible, but gene changes can alter behaviour in many different ways1.
W H, Riege, A, Cherkin
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Polymorphic MHC loci in an asexual fish, the amazon molly (Poecilia formosa; Poeciliidae)
Molecular Ecology, 2008AbstractGenes of the major histocompatibility complex (MHC) encode molecules that control immune recognition and are highly polymorphic in most vertebrates. The remarkable polymorphisms at MHC loci may be maintained by selection from parasites, sexual selection, or both.
Schaschl, H +4 more
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Mating preferences of Amazon mollies (Poecilia formosa) in multi-host populations
Behaviour, 2012Gynogenesis is a peculiar mode of clonal reproduction in which eggs need to be pseudo-fertilized by sperm, but the male genes are not passed on to the offspring. One mating system in which gynogenesis is found involves a unisexual hybrid, the Amazon molly (Poecilia formosa), which typically uses males of its two parental species as sperm donors.
Brandon L. Joachim, Ingo Schlupp
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Cytophotometric evidence for triploidy in hybrids of the gynogenetic fish, Poecilia formosa
Journal of Experimental Zoology, 1965AbstractAmounts of DNA per nucleus were estimated by microphotometry in Feulgen‐stained tissue sections from several species of poeciliid fish and their hybrid offspring. In terms of average nuclear volumes as well as relative DNA levels, the all‐female gynogenetic species P. formosa was indistinguishable from the related bisexual species P.
Rasch, Ellen M. +3 more
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Environmental Biology of Fishes, 2013
Unisexual sperm-dependent species depend on a sexual host for reproduction, and must live in sympatry with their sperm donor. If niche overlap between the species is substantial, the intrinsic faster population growth of the unisexual over sexual species can cause competitive exclusion of the host from resources, causing the demise of the unisexual ...
Laura Alberici da Barbiano +4 more
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Unisexual sperm-dependent species depend on a sexual host for reproduction, and must live in sympatry with their sperm donor. If niche overlap between the species is substantial, the intrinsic faster population growth of the unisexual over sexual species can cause competitive exclusion of the host from resources, causing the demise of the unisexual ...
Laura Alberici da Barbiano +4 more
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Acta ethologica, 2002
The Tamesi molly, Poecilia latipunctata, has a very limited biogeographical range in northeast Mexico. This area is nested within the ranges of the Atlantic molly, Poecilia mexicana, and the unisexual Amazon molly, Poecilia formosa. Based on morphology, especially fin shape, the Tamesi molly has been considered to be a "short-fin" molly.
Andreas Niemeitz +4 more
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The Tamesi molly, Poecilia latipunctata, has a very limited biogeographical range in northeast Mexico. This area is nested within the ranges of the Atlantic molly, Poecilia mexicana, and the unisexual Amazon molly, Poecilia formosa. Based on morphology, especially fin shape, the Tamesi molly has been considered to be a "short-fin" molly.
Andreas Niemeitz +4 more
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EVIDENCE FOR A MONOPHYLETIC ORIGIN OF TRIPLOID CLONES OF THE AMAZON MOLLY, POECILIA FORMOSA
Evolution, 2005Asexual reproduction in vertebrates is rare and generally considered an evolutionary dead end. Asexuality is often associated with polyploidy, and several hypotheses have been put forward to explain this relationship. So far, it remains unclear whether polyploidization in asexual organisms is a frequent or a rare event. Here we present a field study on
Kathrin P, Lampert +3 more
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The development of thyroid neoplasia in old age in the amazon molly, Poecilia formosa
Experimental Gerontology, 1977Abstract In a previous paper we have described the appearance of a thyrotrophin sensitive thyroid neoplasm in an few senile individuals from a laboratory population of guppies, Lebistes reticulatus (Peters). Material has now been examined from the closely related species, Poecilia formosa , the Amazon molly, in which the incidence of thyroid ...
A D, Woodhead, R B, Setlow, R W, Hart
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Proceedings of the Royal Society of London. Series B. Biological Sciences, 1966
The histological study of the homotransplanted pituitary of Poecilia formosa , grafted for 7 weeks in fish that were hypophysectomized 3 weeks after the transplantation, revealed considerable variation in the size and cellular composition of the grafts. However, certain general conclusions were drawn from the study.
M, Olivereau, J N, Ball
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The histological study of the homotransplanted pituitary of Poecilia formosa , grafted for 7 weeks in fish that were hypophysectomized 3 weeks after the transplantation, revealed considerable variation in the size and cellular composition of the grafts. However, certain general conclusions were drawn from the study.
M, Olivereau, J N, Ball
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