The genetic control of the supernatant form of aspartate aminotransferase (AAT) was studied in the cutthroat trout (Salmo clarki) through a series of experimental matings. 509 individuals of eight ...families were examined to determine (1) the number of loci, (2) the mode of inheritance (i.e. disomic or tetrasomic), and (3) the linkage relationship of the loci involved. The variation observed is controlled by a duplicated locus resulting from a presumed tetraploid event of an ancestral salmonid. The inheritance experiments revealed the presence of two disomic loci rather than a single tetrasomic locus, indicating that disomy has been reestablished for the chromosomes carrying the AAT loci. The two families in which linkage between these loci could be tested displayed significant nonrandom segregation between these loci with an estimated frequency of recombination of 30.6%. These results are discussed in regard to the proposed evolution of tetraploidy in the family Salmonidae.
Pallid and shovelnose sturgeon are electrophoretically indistinguishable at 37 loci. They share the same allele at 34 monomorphic loci and have similar allelic frequencies at three polymorphic loci. ...This complete lack of genetic divergence between species is unusual among fish that have been studied. The close genetic similarity is apparently due to recent or incomplete reproductive isolation accompanied by rapid morphological differentiation.
We detected hybrids between the bull trout (Salvelinus confluentus) and the brook trout (S. fontinalis) in three samples from the Upper Columbia River drainage in Montana using 10 isozyme loci that ...differentiate these species. The occurrence of only first generation, male hybrids indicates that these hybrids are almost certainly sterile. We counted 10 meristic characters from all of the bull trout, brook trout, and their hybrids in the sample from the South Fork of Lolo Creek. Univariate and multivariate analyses of the meristic data conclusively indicated that the hybrids are not meristically intermediate to the parental species. The hybrids had counts higher than either of the parental species or counts similar to the parental species with the higher count. The consistent tendency for the hybrids to have high meristic counts is suggested to be due to reduced developmental rate caused by genetic incompatibility between the parental genomes.
We describe protein variation at 34 genetic loci among 23 populations of the salamander genus Dicamptodon. Four major genetic groups emerge, congruent with the four morphological groups detected by ...Nussbaum (1976). The genetic data confirm the specific identity of D. copei. However, recognition of Idaho populations as D. aterrimus is warranted on the basis of equivalently great genetic divergence from Coastal-Cascade D. ensatus and D. copei. The lineage divergence time of this major phylogenetic event is estimated at 7.5 MYBP, in contrast to estimates placing it in the late Pleistocene.
The Population Biology of Invasive Specie Sakai, Ann K.; Allendorf, Fred W.; Holt, Jodie S. ...
Annual review of ecology and systematics,
01/2001, Letnik:
32
Journal Article
Contributions from the field of population biology hold promise for understanding and managing invasiveness; invasive species also offer excellent opportunities to study basic processes in population ...biology. Life history studies and demographic models may be valuable for examining the introduction of invasive species and identifying life history stages where management will be most effective. Evolutionary processes may be key features in determining whether invasive species establish and spread. Studies of genetic diversity and evolutionary changes should be useful for understanding the potential for colonization and establishment, geographic patterns of invasion and range expansion, lag times, and the potential for evolutionary responses to novel environments, including management practices. The consequences of biological invasions permit study of basic evolutionary processes, as invaders often evolve rapidly in response to novel abiotic and biotic conditions, and native species evolve in response to the invasion.
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