Genetic survey of caribou populations using microsatellite DNA

Microsatellite loci are highly variable regions of eukaryotic DNA that consist of tandemly repeated sequences of one to six nucleotides in length. The use of microsatellites and the Polymerase Chain Reaction (PCR) are powerful tools for quantifying genetic variation within and among individual populations. Recently, we have developed primers for caribou that amplify 4 microsatellite loci. These microsatellite loci were used to survey the genetic variation in populations of Barren-ground caribou (Rangifer tarandus groenlandicus), Peary caribou (R.t. pearyi) and Woodland caribou (R.t. caribou) of Canada. The four loci examined were all polymorphic, revealing high levels of heterozygosity (> 0.74) in all of the study populations

Monozygotic Twin Wolves with Divergent Life Histories

Genetic evidence for monozygotic (identical) twinning in mammalian species is rare in the literature. Here we report what may be the first pair of monozygotic twins identified in a wild caniform carnivore, the grey wolf (Canis lupus). One of these individuals remained in its natal population of Banks Island, Northwest Territories, Canada, while its twin migrated across the polar sea ice to the mainland. This suggests divergent life history strategies in genetically identical individuals, making this incidence of twinning particularly interesting.Il est rare que la documentation fasse état de preuves génétiques à l’égard de jumeaux monozygotes (identiques) chez les espèces de mammifères. Ici, nous faisons mention de ce qui pourrait être la première paire de jumeaux monozygotes identifiée chez un carnivore caniforme sauvage, le loup gris (Canis lupus). Un de ces individus est resté au sein de sa population natale de l’île Banks, dans les Territoires du Nord-Ouest, au Canada, tandis que son jumeau a migré jusqu’à la terre ferme au moyen de la glace polaire. Cela laisse entrevoir des stratégies de cycle biologique différentes chez des individus génétiquement identiques, ce qui rend cette gémellité particulièrement intéressante

Genetic relationships of three Yukon caribou herds determined by DNA typing

In this paper we examine genetic relationships of caribou (Rangifer tarandus caribou) in the Aishihik, Chisana, and Wolf Lake herds in the Yukon using DNA fingerprinting. The assignment test used in this analysis showed that the caribou herds were distinct. This finding is consistent with movement data from radio-collared caribou which demonstrates home range fidelity. We found a high level of heterozygosity and a genetic basis for population boundaries. DNA fingerprinting may provide an effective means to compare ecological and genetic relationships

Monozygotic Twin Wolves with Divergent Life Histories

Genetic evidence for monozygotic (identical) twinning in mammalian species is rare in the literature. Here we report what may be the first pair of monozygotic twins identified in a wild caniform carnivore, the grey wolf (Canis lupus). One of these individuals remained in its natal population of Banks Island, Northwest Territories, Canada, while its twin migrated across the polar sea ice to the mainland. This suggests divergent life history strategies in genetically identical individuals, making this incidence of twinning particularly interesting.Il est rare que la documentation fasse état de preuves génétiques à l’égard de jumeaux monozygotes (identiques) chez les espèces de mammifères. Ici, nous faisons mention de ce qui pourrait être la première paire de jumeaux monozygotes identifiée chez un carnivore caniforme sauvage, le loup gris (Canis lupus). Un de ces individus est resté au sein de sa population natale de l’île Banks, dans les Territoires du Nord-Ouest, au Canada, tandis que son jumeau a migré jusqu’à la terre ferme au moyen de la glace polaire. Cela laisse entrevoir des stratégies de cycle biologique différentes chez des individus génétiquement identiques, ce qui rend cette gémellité particulièrement intéressante

A Paired-Comparision of the MultiFunction CardioGramsm (MCG) and Sestamibi SPECT Myocardial Perfusion Imaging (MPI) to Quantitative Coronary Angiography for the Detection of Relevant Coronary Artery Obstruction (≥70%) - A Single-Center Study of 116 Consecutive Patients Referred for Coronary Angiography

<p><b>Background:</b> An analysis of the US National Cardiovascular Data Registry has revealed that only 38% of patients referred for coronary angiography after non-invasive coronary testing have relevant coronary obstruction (CO) (&#8805;70%) of one or more coronary arteries.</p><p><b>Methods:</b> A single-center trial was undertaken in 165 consecutive, symptomatic patients with either known or suspected coronary disease and/or valve disease(VHD) who agreed to undergo cardiac catheterization and coronary angiography if stress myocardial perfusion imaging was abnormal. A total of 116 patients with abnormal SPECT MPI tests, persistent chest pain, or significant VHD underwent final analysis. An MCG coronary obstruction (CO) score of &#8805; 4.0 was considered indicative of relevant CO (&#8805;70%) in one or more coronary arteries. Angiographic results were finalized by consensus of two angiographers.</p><p><b>Results:</b> CO (&#8805;70%) was present in 53 of 116 patients (46%). The MCG CO score was significantly higher for patients with relevant CO (5.4 &#177; 1.9 vs. 2.5 &#177; 1.9). The MCG correctly classified 103 of the 116 patients (89%) enrolled in the study as either having or not having CO (&#8805;70%) (sensitivity- 91%; specificity- 87%; NPV- 92%; PPV- 86%). SPECT MPI was abnormal in 99 of the 116 (85%) patients undergoing catheterization, but correctly classified only 54 of the 116 patients (47%) entered in the study as either having or not having relevant CO (sensitivity-85%; specificity-14%; NPV - 53%; PPV- 45%).</p><p><b>Conclusions:</b> The MCG was shown in this paired-comparison trial with SPECT MPI to safely and accurately identify patients with relevant CO (&#8805;70%) prior to catheterization.</p