scholarly journals Genetic variation in transferrin as a predictor for differentiation and evolution of caribou from eastern Canada

Rangifer ◽  
1991 ◽  
Vol 11 (2) ◽  
pp. 65 ◽  
Author(s):  
Knut H. Røed ◽  
Michael A. D. Ferguson ◽  
Michel Crête ◽  
Tom A. Bergerud
Keyword(s):  
High Frequency ◽  
Gel Electrophoresis ◽  
Rangifer Tarandus ◽  
Genetic Differences ◽  
The Other ◽  
Baffin Island ◽  
Eastern Canada ◽  
Low Frequencies ◽  
Svalbard Reindeer ◽  
Rangifer Tarandus Groenlandicus

Polycrylamide gel electrophoresis was used to analyse tranferrrin variation in caribou populations from Manitoba, Ontario, Québec/Labrador, and from Baffin Island, Northwest Territories in eastern Canada. The transferrin allele frequencies in these populations were compared with those previously reported for Canadian barren-ground caribou, Rangifer tarandus groenlandicus, Alaska caribou, R.t. grand, Peary caribou, R.t. pearyi, Svalbard reindeer, R.t. pla-tyrhynchus, and Eurasian tundra reindeer, R.t. tarandus. A total of twenty different alleles was detected in the analysed material, considerable genetic heterogeneity being detected among regions. Three alleles that were relatively common in caribou from Ontario, Manitoba and Québec/Labrador, were not present in R.t. grand, R.t. pearyi, R.t. tarandus or R.t. platyrhynchus, and present only at very low frequencies 'm R.t. groenlandicus. These findings, together with genetic identity analyses, suggest that the caribou in Manitoba, Ontario, and Québec/Labrador are mainly of the R.t. caribou type, and that little interbreeding has occurred with other subspecies. The large genetic distance in the transferrin locus between R.t. caribou and other subspecies of reindeer/caribou suggests that, during the Wisconsin glaciation the ancestral populations of R.t. caribou survived in a refugium different from that of the ancestral populations of the other subspecies. Significant genetic differences between Baffin Island caribou and all other populations were mainly due to the presence of one allele that was in high frequency in Baffin Island caribou, but that was absent, or present in very low frequencies, in all other reindeer/caribou populations. The genetic differences between Baffin Island caribou and the other subspecies were greater than the differences between several of the currently recognized subspecies.

scholarly journals Physics Augmented U-Net: A High-Frequency Aware Generative Prior for Microscopy

2021 ◽  
Author(s):  
Jathurshan Pradeepkumar ◽  
Mithunjha Anandakumar ◽  
Vinith Kugathasan ◽  
Andrew Seeber ◽  
Dushan N Wadduwage
Keyword(s):  
High Frequency ◽  
Forward Model ◽  
The Other ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Experimental Conditions ◽  
Low Frequencies ◽  
High Frequencies ◽  
Proposed Model ◽  
Microscopy Images

A key challenge in optical microscopy is to image fast at high-resolution. To address this problem, we propose "Physics Augmented U-Net", which combines deep learning and structured illumination microscopy (SIM). In SIM, the structured illumination aliases out-of-band high-frequencies to the passband of the microscope; thus SIM captures some high-frequencies even when the image is sampled at low-resolution. To utilize these features, we propose a three-element method: 1) a modified U-Net model, 2) a physics-based forward model of SIM 3) an inference algorithm combining the two models. The modified U-Net architecture is similar to the seminal work, but the bottleneck is modified by concatenating two latent vectors, one encoding low-frequencies (LFLV), and the other encoding high-frequencies (HFLV). LFLV is learned by U-Net contracting path, and HFLV is learned by a second encoding path. In the inference mode, the high-frequency encoder is removed; HFLV is then optimized to fit the measured microscopy images to the output of the forward model for the generated image by the U-Net. We validated our method on two different datasets under different experimental conditions. Since a latent vector is optimized instead of a 2D image, the inference mode is less computationally complex. The proposed model is also more stable compared to other generative prior-based methods. Finally, as the forward model is independent of the U-Net, Physics Augmented U-Net can enhance resolution on any variation of SIM without further retraining.

Transferrin variation in caribou (Rangifer tarandus L.) on the Canadian Arctic islands

1986 ◽  
Vol 64 (1) ◽  
pp. 94-98 ◽  
Author(s):  
K. H. Røed ◽  
H. Staaland ◽  
E. Broughton ◽  
D. C. Thomas
Keyword(s):  
Genetic Distance ◽  
Gel Electrophoresis ◽  
Rangifer Tarandus ◽  
Polyacrylamide Gel Electrophoresis ◽  
Canadian Arctic ◽  
High Arctic ◽  
Polyacrylamide Gel ◽  
Common Allele ◽  
Island Populations ◽  
Svalbard Reindeer

Polyacrylamide gel electrophoresis was used to analyse transferrin variation in caribou from the Canadian Arctic islands. Sixteen alleles were detected in Peary caribou (Rangifer tarandus pearyi). The most common allele was TfG2, which increased in frequency from 0.167 at the Boothia Peninsula to 0.236 in the Peel population and 0.340 in the Parry population. The presence of this allele, which is the most common allele in Svalbard reindeer (R. t. platyrhynchus) and not detected in Norwegian reindeer (R. t. tarandus), suggests a common origin for the Peary caribou and the Svalbard reindeer. The large genetic distance in the transferrin locus between continental and island populations suggests the isolation of a High Arctic population in a northern refugium during the Wisconsin glaciation.

scholarly journals The frequency of antlerless females among Svalbard reindeer

Rangifer ◽  
1998 ◽  
Vol 18 (6) ◽  
pp. 81 ◽  
Author(s):  
Bente W. Jacobsen ◽  
Jonathan E. Colman ◽  
Eigil Reimers
Keyword(s):  
High Frequency ◽  
Rangifer Tarandus ◽  
Chi Square ◽  
Svalbard Reindeer

The distribution of females with no, one and two antlers was recorded during July 1994 in Svalbard reindeer, Rangifer tarandus platyrhynchus, and compared wirh 1974 data from Reimers (1993) and Larsen (1977). On Reinsdyrflya, 50% of the females were anrlerless, 16% one antlered and 34% rwo antlered. In Nordenskiold Land, 2% of the females were antlerless, 1% one antlered and 97% two antlered. These percentages have not changed since Reimers' study in 1974 in Reinsdyrflya (Chi square 2= 1.16, P > 0.05) and Nordenskiold Land (Chi square 2 = 1.69, P > 0.05). The reason for the high frequency of anrlerless females on Reinsdyrflya is not understood.

scholarly journals Transferrin variation and evolution of Canadian barren-ground caribou

Rangifer ◽  
1990 ◽  
Vol 10 (3) ◽  
pp. 385 ◽  
Author(s):  
Knut H. Røed ◽  
D. C. Thomas
Keyword(s):  
Genetic Variation ◽  
Allele Frequency ◽  
Gel Electrophoresis ◽  
Rangifer Tarandus ◽  
High Arctic ◽  
Ancestral Population ◽  
Allele Frequency Distribution ◽  
Frequency Pattern ◽  
Barren Ground ◽  
Svalbard Reindeer

Blood samples were obtained from 95 barren-ground caribou (Rangifer tarandus groenlandicus) of the Beverly herd in Northwest Territories, Canada. Polyacrylamid gel electrophoresis was used to score for genetic variation in the locus coding for transferrin. The pattern of allele frequency distribution are compared with previously reported values of Eurasian tundra reindeer (R.t. tarandus), Alaska caribou (R.t. granti), Peary caribou (R.t. pearyi), and Svalbard reindeer (R.t. platyrhynchus). In the Beverly herd a total of 21 different transferrin alleles were detected. The amount of genetic variation was higher in the Canadian barren-ground caribou than what has been detected in other subspecies of reindeer/caribou. Highly gene-tical differences in the allele frequencies were detected between the Canadian barren-ground caribou and the other subspecies. The genetic identity analyses indicates approximately the same amount of genetic differentiation when the Canadian barren-ground caribou are compared with Alaska caribou as with the Peary caribou. The allele frequency pattern could be explained by a possible origin of the Canadian barren-ground caribou from an ancestral population which was genetical influenced by animals surviving the We-ichselian glaciation in refugia both in high Arctic, in Beringia, and south of the ice sheet.

Surplus killing as exemplified by wolf predation on newborn caribou

1985 ◽  
Vol 63 (2) ◽  
pp. 295-300 ◽  
Author(s):  
Frank L. Miller ◽  
Anne Gunn ◽  
Eric Broughton
Keyword(s):  
Northwest Territories ◽  
Canis Lupus ◽  
Rangifer Tarandus ◽  
The Other ◽  
Wolf Predation ◽  
Barren Ground ◽  
Rangifer Tarandus Groenlandicus

We searched for newborn calf carcasses of migratory barren-ground caribou (Rangifer tarandus groenlandicus) in June 1982 in the Northwest Territories. On 17 June, we found 34 calves killed by wolves (Canis lupus), clumped in a 3-km2 area. The calves had been killed apparently within minutes of each other and about 24 h before being found. Wolves had not fed on 17 of the carcasses and had only partially eaten the other 17. Ground observations illustrate the speed of and efficiency with which wolves can kill calves: a single wolf killed three calves on one occasion and three and possibly four calves on a second occasion at average kill rates of 1 calf/min, and 1 calf/8 min or 1 calf/6 min between the first and last deaths. We attributed the surplus killing of newborn caribou calves to their high densities and their vulnerability on the calving grounds. We recommend that a distinction be made between "surplus killing" and "excessive killing" by predators.

An EMI Immunity Study of TMR Heads in Quasi-Static Tester due to the Direction of Sweeping Frequency

2009 ◽  
Vol 152-153 ◽  
pp. 447-450 ◽  
Author(s):  
Apirat Siritaratiwat ◽  
A. Kruesubthaworn ◽  
V. Ungvichian
Keyword(s):  
Energy Level ◽  
Electromagnetic Interference ◽  
High Frequency ◽  
The Other ◽  
Barkhausen Noise ◽  
Comparative Effect ◽  
Low Frequencies ◽  
Head Gimbal Assembly ◽  
Test Parameters ◽  
Recording Heads

This report aims to investigate a comparative effect of Electromagnetic Interference (EMI) on recording heads due to sweeping directions of low-to-high and high-to-low frequencies. Four selected Quasi-Static Tester (QST) parameters; MR resistance, MR amplitude asymmetry, Barkhausen noise and Hysteresis, are used for monitoring the effect of EMI on Head Gimbal Assembly (HGA). It is undoubtedly found that the Asymmetry and Hysteresis parameters provide insufficient indication of EMI effect for both sweeping frequency directions. On the other hand, it is discovered that the sweeping direction of the low-to-high frequency is more effective to two test parameters; MR resistance and Barkhausen noise, than the other direction. The dramatic energy accumulation is possibly explained this phenomenon but this energy level is not high enough to cause the Hysteresis change.

scholarly journals Transferrin variation and evolution of Alaskan reindeer and caribou, Rangifer tarandus L.

Rangifer ◽  
1986 ◽  
Vol 6 (2) ◽  
pp. 247 ◽  
Author(s):  
Knut H. Røed ◽  
Ken R. Whitten
Keyword(s):  
Allele Frequency ◽  
Frequency Distribution ◽  
Gel Electrophoresis ◽  
Rangifer Tarandus ◽  
Polyacrylamide Gel Electrophoresis ◽  
Polyacrylamide Gel ◽  
Allele Frequency Distribution ◽  
Common Allele ◽  
Frequency Distributions ◽  
Svalbard Reindeer

Polyacrylamide gel electrophoresis was used to analyse transferrin variation in wild caribou (Rangifer tarandus granti) and domestic reindeer (R.t. tarandus) from Alaska. Eighteen alleles were detected in caribou and ten alleles were detected in reindeer. The most common allele was Tf 1 with a frequency of 0.304 and 0.408 in caribou and reindeer, respectively. The allele frequency distributions were significantly different in reindeer and caribou. This finding, together with the absence in reindeer of nine alleles present in caribou, suggests that little genetic exchange has taken place between caribou and reindeer in Alaska. The allele frequency distribution in Alaska caribou and reindeer are compared with those for other populations of caribou and reindeer. This comparison indicates that Alaskan caribou as well as Eurasian reindeer have evolved from a common ancesteral population different from the ancesteral population of Peary cairbou (R.t. pearyi) and Svalbard reindeer (R.t. platyrhynchus).

scholarly journals Chance or Necessity—The Fungi Co−Occurring with Formica polyctena Ants

Insects ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 204
Author(s):  
Igor Siedlecki ◽  
Michał Gorczak ◽  
Alicja Okrasińska ◽  
Marta Wrzosek
Keyword(s):  
Molecular Identification ◽  
High Frequency ◽  
Its Rdna ◽  
The Other ◽  
Formica Polyctena ◽  
Ant Nests ◽  
Mutualistic Fungi ◽  
The Tropics ◽  
High Diversity ◽  
Better Than

Studies on carton nesting ants and domatia−dwelling ants have shown that ant–fungi interactions may be much more common and widespread than previously thought. Until now, studies focused predominantly on parasitic and mutualistic fungi–ant interactions occurring mostly in the tropics, neglecting less−obvious interactions involving the fungi common in ants’ surroundings in temperate climates. In our study, we characterized the mycobiota of the surroundings of Formica polyctena ants by identifying nearly 600 fungal colonies that were isolated externally from the bodies of F. polyctena workers. The ants were collected from mounds found in northern and central Poland. Isolated fungi were assigned to 20 genera via molecular identification (ITS rDNA barcoding). Among these, Penicillium strains were the most frequent, belonging to eight different taxonomic sections. Other common and widespread members of Eurotiales, such as Aspergillus spp., were isolated very rarely. In our study, we managed to characterize the genera of fungi commonly present on F. polyctena workers. Our results suggest that Penicillium, Trichoderma, Mucor, Schwanniomyces and Entomortierella are commonly present in F. polyctena surroundings. Additionally, the high diversity and high frequency of Penicillium colonies isolated from ants in this study suggest that representatives of this genus may be adapted to survive in ant nests environment better than the other fungal groups, or that they are preferentially sustained by the insects in nests.

Normal Synaptonemal Complex and Abnormal Recombination Nodules in Two Alleles of the Drosophila Meiotic Mutant mei-W68

Genetics ◽  
2003 ◽  
Vol 163 (4) ◽  
pp. 1337-1356 ◽  
Author(s):  
Adelaide T C Carpenter
Keyword(s):  
Electron Microscopy ◽  
Synaptonemal Complex ◽  
High Frequency ◽  
Serial Section ◽  
The Other ◽  
Wild Type ◽  
Recombination Nodules ◽  
Section Electron ◽  
Serial Section Electron Microscopy ◽  
Section Electron Microscopy

Abstract The meiotic phenotypes of two mutant alleles of the mei-W68 gene, 1 and L1, were studied by genetics and by serial-section electron microscopy. Despite no or reduced exchange, both mutant alleles have normal synaptonemal complex. However, neither has any early recombination nodules; instead, both exhibit high numbers of very long (up to 2 μm) structures here named “noodles.” These are hypothesized to be formed by the unchecked extension of identical but much shorter structures ephemerally seen in wild type, which may be precursors of early recombination nodules. Although the mei-W68L1 allele is identical to the mei-W681 allele in both the absence of early recombination nodules and a high frequency of noodles (i.e., it is amorphic for the noodle phene), it is hypomorphic in its effects on exchange and late recombination nodules. The differential effects of this allele on early and late recombination nodules are consistent with the hypothesis that Drosophila females have two separate recombination pathways—one for simple gene conversion, the other for exchange.

scholarly journals Recombination of Ty elements in yeast can be induced by a double-strand break.

Genetics ◽  
1995 ◽  
Vol 140 (1) ◽  
pp. 67-77 ◽  
Author(s):  
A Parket ◽  
O Inbar ◽  
M Kupiec
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Strand Break ◽  
Double Strand Break ◽  
The Other ◽  
Direct Repeats ◽  
Yeast Saccharomyces Cerevisiae ◽  
Low Frequencies ◽  
Ty Elements ◽  
Main Family

Abstract The Ty retrotransposons are the main family of dispersed repeated sequences in the yeast Saccharomyces cerevisiae. These elements are flanked by a pair of long terminal direct repeats (LTRs). Previous experiments have shown that Ty elements recombine at low frequencies, despite the fact that they are present in 30 copies per genome. This frequency is not highly increased by treatments that cause DNA damage, such as UV irradiation. In this study, we show that it is possible to increase the recombination level of a genetically marked Ty by creating a double-strand break in it. This break is repaired by two competing mechanisms: one of them leaves a single LTR in place of the Ty, and the other is a gene conversion event in which the marked Ty is replaced by an ectopically located one. In a strain in which the marked Ty has only one LTR, the double-strand break is repaired by conversion. We have also measured the efficiency of repair and monitored the progression of the cells through the cell-cycle. We found that in the presence of a double-strand break in the marked Ty, a proportion of the cells is unable to resume growth.

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