Sympatric Speciation
Mostrando 13-24 de 33 artigos, teses e dissertações.
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13. When houseguests become parasites: Sympatric speciation in ants
National Academy of Sciences.
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14. Reticulate sympatric speciation in Cameroonian crater lake cichlids
BioMed Central.
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15. Conflict between nuclear and mitochondrial DNA phylogenies of a recent species radiation: What mtDNA reveals and conceals about modes of speciation in Hawaiian crickets
It has been asserted that recent mtDNA phylogenies support the plausibility of sympatric speciation, long considered a controversial mechanism of the origin of species. If such inferences are reliable, mtDNA phylogenies should be congruent with phylogenies based on other data. In previous work, a mtDNA phylogeny suggested that diversification of the Hawaiian
National Academy of Sciences.
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16. Postzygotic isolating factor in sympatric speciation in Rhagoletis flies: Reduced response of hybrids to parental host-fruit odors
Rhagoletis pomonella is a model for sympatric speciation (divergence without geographic isolation) by means of host-plant shifts. Many Rhagoletis species are known to use fruit odor as a key olfactory cue to distinguish among their respective host plants. Because Rhagoletis rendezvous on or near the unabscised fruit of their hosts to mate, behavioral prefere
National Academy of Sciences.
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17. Ecologically dependent postmating isolation between sympatric host forms of Neochlamisus bebbianae leaf beetles
Ecological speciation is the promotion of reproductive isolation via the divergent adaptation of populations to alternative environments. A prediction peculiar to ecological speciation is that hybrids between such populations should be adapted poorly to parental environments, yielding reduced fitness and postmating isolation. However, F1 analyses alone canno
National Academy of Sciences.
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18. Selective maintenance of allozyme differences among sympatric host races of the apple maggot fly
Whether phytophagous insects can speciate in sympatry when they shift and adapt to new host plants is a controversial question. One essential requirement for sympatric speciation is that disruptive selection outweighs gene flow between insect populations using different host plants. Empirical support for host-related selection (i.e., fitness trade-offs) is s
The National Academy of Sciences of the USA.
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19. Ancient mitochondrial DNA and morphology elucidate an extinct island radiation of Indian Ocean giant tortoises (Cylindraspis).
Ancient mitochondrial DNA sequences were used for investigating the evolution of an entire clade of extinct vertebrates, the endemic tortoises (Cylindraspis) of the Mascarene Islands in the Indian Ocean. Mitochondrial DNA corroborates morphological evidence that there were five species of tortoise with the following relationships: Cylindraspis triserrata ((C
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20. Sympatric speciation by sexual conflict
It is well established that sexual conflict can drive an endless coevolutionary chase between the sexes potentially leading to genetic divergence of isolated populations and allopatric speciation. We present a simple mathematical model that shows that sexual conflict over mating rate can result in two other general regimes. First, rather than “running away
National Academy of Sciences.
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21. Divergent selection during speciation of Lake Malawi cichlid fishes inferred from parallel radiations in nuptial coloration
Repeated evolution of the same phenotypic difference during independent episodes of speciation is strong evidence for selection during speciation. More than 1,000 species of cichlids, >10% of the world's freshwater fish species, have arisen within the past million years in Lakes Malawi and Victoria in eastern Africa. Many pairs of closely related sympatric s
National Academy of Sciences.
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22. Alternative adaptations, speciation, and phylogeny (A Review)
Alternative adaptations—different adaptive phenotypes maintained in the same life stage and the same population but not necessarily simultaneously expressed in the same individual—represent contrasting character sets produced by the same genome, in effect allowing a single species to occupy more than one sympatric niche. Such alternatives are particularl
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23. Disruptive sexual selection against hybrids contributes to speciation between Heliconius cydno and Heliconius melpomene.
Understanding the fate of hybrids in wild populations is fundamental to understanding speciation. Here we provide evidence for disruptive sexual selection against hybrids between Heliconius cydno and Heliconius melpomene. The two species are sympatric across most of Central and Andean South America, and coexist despite a low level of hybridization. No-choice
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24. Gene Flow and Natural Selection in the Origin of Drosophila Pseudoobscura and Close Relatives
The divergence of Drosophila pseudoobscura and close relatives D. persimilis and D. pseudoobscura bogotana has been studied using comparative DNA sequence data from multiple nuclear loci. New data from the Hsp82 and Adh regions, in conjunction with existing data from Adh and the Period locus, are examined in the light of various models of speciation. The pri