Effects of specialization on genetic differentiation in sister species of bark beetles

Article Abstract:

Specialization and its effects on genetic differentiation in sister species of bark beetles are discussed. The study is novel in that it uses phylogeny estimate to establish directionality in the evolution of specialization to evaluate correlates and consequences. D. jeffreyi is the specialist in the study and D. ponderosae is the generalist. Overall levels of allozyme variation were similar. In the three shared polymorphic loci studied, each species had the same number, in total, of alleles, but allele frequencies varied with population.

Evolution (Biology), Trees, Trees (Plants), Origin of species, Dendroctonus, Phytophagous insects, Bark beetles

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Are flightless Galapaganus weevils older that the Galapagos Islands they inhabit?

Article Abstract:

The flightless Galapaganus weevils and whether or not they are older that the Galapagos Islands they inhabit are discussed. Sequences of the mtDNA locus encoding cytochrome oxidase subunit I were taken from samples of seven species occurring in different ecological zones of the oldest southeastern islands and the central island. Two well-supported clades that correspond to the species groups already defined by morphological characters were shown. They are from the most parsimonious tree obtained. The estimate based on a mtDNA clock is greater than the geological ages of the extant islands, but agrees well with molecular dating of other endemic animals. The explanation proposed involves submerged islands.

Argentina, Oceania, Beetles, Galapagos Islands, Island ecology, Submerged lands

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Congruence between allozyme and cytochrome b gene sequence data in assessing genetic differentiation within the Iberian endemic Chondrostoma lemmingii (Pisces: Cyprinidae)

Article Abstract:

Allozyme and cytochrome b gene sequence data have been analyzed to assess genetic differentiation within the endemic Iberian Chondrostoma lemmingii (Pisces: Cyprinidae). Ten populations were studied using 26 loci encoding 19 enzymes and all the nucleotide sequence of the mitochondrial cytochrome b gene. The differentiation process was the result not only of hydrographical basin isolation. It was also the result of an ancient endorrheism event that took placed before hydrographical configuration. That might explain the marked differences of the Duero basic population.

Spain, Physiological aspects, Heredity, Iberian Peninsula, Cytochromes, Isoenzymes, Lemmings

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