Wyniki wyszukiwania

1

Non-disjunction frequency in male complex Robertsonian heterozygotes of the common shrew

100%

Fedyk S., Chetnicki W.

Acta Theriologica

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2010

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tom 55

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nr 1

1-8

Common shrews display two types of Robertsonian (Rb) heterozygosity: simple (where CIII configurations are formed at meiosis I) and complex (which have longer meiotic chains or rings). Based on an analysis of large sample sizes (over 100) of MII cells per specimen, we estimated the non-disjunction frequency in seven Rb homozygotes and 21 complex Rb heterozygotes (CIV and CV) of Sorex araneus Linnaeus, 1758. The analysis showed high betweenindividual variability. The mean level of non-disjunction in homozygotes (2.01%) was significantly lower than in CIV and CV heterozygotes (4.27% and 5.78%, respectively). The study demonstrated that non-disjunction frequency in male CIV and CV heterozygotes was similar to that in simple heterozygotes in the common shrew.

2

Morphometric difference between the Novosibirsk and Tomsk chromosome races of Sorex araneus in a zone of parapatry

84%

Polyakov A. V., Onischenko S. S., Ilyashenko V. B., Searle J. B., Borodin P. M.

Acta Theriologica

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2002

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tom 47

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nr 4

A hybrid zone between the Novosibirsk and Tomsk chromosome races of the common shrew Sorex araneus Linnaeus, 1758 was found near Novosibirsk city (West Siberia, Russia) in an area unimpeded by geographic barriers. In this zone, the shrews of both races and their hybrids were trapped and karyotyped and 22 features of their cranial and postcranial skeleton were measured. Canonical discriminant analysis revealed 3 distinct groups of individuals, which corresponded to the 3 karyotypic categories involved in the analysis. The first discriminant function reflected the differences in the size of skeletal elements. The Novosibirsk shrews and the hybrids were significantly smaller than the Tomsk shrews. The second discriminant function was interpreted as a parameter of skeletal proportionality. The hybrids were significantly less proportional than the parental races. This study revealed one of the clearest examples of morphological differentiation between chromosome races of the common shrew.

3

A hybrid zone between the chromosomal races Legucki Mlyn and Popielno of the common shrew in North-Eastern Poland: preliminary results

84%

Moska M.

Acta Theriologica

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2003

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tom 48

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nr 4

A newly discovered hybrid zone between two karyotypic races, Łęgucki Młyn (g/r, h/k, i/o, j/l, m/n, p, q) and Popielno (g/r, h/q, i/k, j/l, m/n, o, p), of the common shrew Sorex araneus Linnaeus, 1758 has been studied in north-eastern Poland. In the Łęgucki Młyn/Popielno hybrid zone the complex heterozygotes form theoretically only short meiotic chain configurations, consisting of four or five elements. In all hybrid populations a high frequency of complex heterozygotes was observed, varying from 0.30 to 0.43 between localities. In the centre of the hybrid zone the frequencies of telocentrics h and k increased. In two individuals of the hybrid populations (Krutyń I and Krutyń II), homozygous telocentric for chromosome arms h, i, k, o and q were observed.

4

Evolution of the common shrew Sorex araneus: chromosomal and molecular aspects

84%

Wojcik J. M., Ratkiewicz M., Searle J. B.

Acta Theriologica. Supplement

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2002

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tom 47

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nr 1

We review data on the chromosomal variation in the common shrew Sorex araneus Linnaeus, 1758 in the context of recent molecular findings. The article considers all aspects of chromosomal variation in this species: within-population polymorphism, karyotypic races, hybrid zones between karyotypic races, chromosomal evolution, and speciation. The recent molecular data provide vital information on different evolutionary processes such as inbreeding, genetic drift, population expansion, and selective forces. In particular, the molecular data challenge traditional models for the fixation of chromosomal variants, provide new insights into the manner of spread of such variants once they are formed and allow in-depth analysis of gene exchange between karyotypic races.

5

Maximization of the frequency of recombinants in the hybrid zones of Sorex araneus in northern Poland

84%

Szalaj K. A., Fedyk S., Banaszek A., Chetnicki W.

Acta Theriologica

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1995

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tom 40

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nr 3

We studied populations of Sorex araneus Linnaeus, 1758 in the upper Drwęca River valley and in the vicinity of Lake Szeląg Wielki. We found that the cline of frequency of metacentric np decays in the Drwęca River valley, which results in a smooth transition between the Stobnica race (karyotype hi, ko, gm, np) and the Laska race (hi, ko, gm). However, on the west shore of Lake Szeląg Wielki the cline of frequency of metacentric gm disappears. Reduction of frequencies of autosomes np and gm makes possible broadening of the ciines of metacentrics gr and mn, originating from the Łęgucki Mtyn race. This results in a reduction of the number of hybrids and maximization of frequency of recombinants (hi, ko, gr, mn), which reaches the value of 1.0 in the populations located on the west shore of the lake. We compared studied populations with those in the Pasłęka River valley, and those between the Pasłęka and Drwęca Rivers valleys. We also discussed the maximization of the frequency of recombinants as a mechanism enhancing fertility of hybrid populations.

6

A hybrid zone between the Kirillov and Petchora chromosomal races of the common shrew (Sorex araneus L., 1758) in northeastern European Russia: a preliminary description

67%

Pavlova S. V., Shchipanov N. A.

Acta Theriologica

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2014

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tom 59

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nr 3

Karyotypes of the Petchora and Kirillov chromosomal races of the common shrew differ by six Robertsonian metacentrics with monobrachial homology, such that interracial F1 hybrids produce a ring-of-six configuration at meiosis I and are expected to suffer infertility. Mapping of 52 karyotyped individuals by using a unique global positioning system (GPS) revealed that the Kirillov-Petchora hybrid zone is positioned close to the river Mezen, which separated these races, and so may limit the migration of shrews across the contact zone. Although the population density of shrews was found to be markedly different with respect to habitats, the zone runs through a mosaic of habitats that are similar for both the Petchora and the Kirillov sides. This is one of the narrowest chromosomal hybrid zones among those studied in Sorex araneus with a standard cline width of about 1 km. The center of the cline is located on a bank occupied by the Petchora race at a distance of 0.4 km away from a riverine barrier. Interestingly, both the Kirillov race and hybrid individuals were found on a small island in the middle of a river fully flooded each spring. The frequencies of karyotypic variants allow us to consider the zone as an example of a bimodal zone. New Robertsonian and de novo whole-arm reciprocal translocations (WART) chromosomal variants found in the zone could be regarded as evidences of current evolutionary process in chromosomal hybrid zones.

7

Habitat use by Carrion Crows Corvus corone corone and Hooded Crows C. c. cornix and their hybrids in eastern Germany

67%

Randler C.

Acta Ornithologica

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2007

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tom 42

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nr 2

191-194

8

The location of the Mus musculus-M.domesticus hybrid zone in the Balkans: clues from morphology

67%

Macholan M., Krystufek B., Vohralik V.

Acta Theriologica

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2003

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tom 48

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nr 2

Three morphological characters were used to depict the position of the hybrid zone between two species of house mice, M. musculus Linnaeus, 1758 and M. domesticus Schwarz et Schwarz, 1943, across a vast area covering countries of the former Yugoslavia, Albania, Bulgaria and Greece. Quantitative approach based on a morphological index (MI), resembling the hybrid index widely used in allozyme-based genetic studies, was used. The zone crosses Slovenia south of the Sava River, and then follows the Dinaric Mts to Montenegro and northern Albania. Contrary to many previously published results, the zone was found to run parallel with northern borders of Albania and the former Yugoslavian Macedonia, about 150 km north of the Greek border, thus giving its course rather "shallow" appearance at this part of the Balkan Peninsula.

9

A taxonomical re-evaluation of the Valais chromosome race of the common shrew Sorex araneus [Insectivora: Soricidae]

67%

Brunner H., Lugon-Moulin N., Balloux F., Fumagalli L., Hausser J.

Acta Theriologica

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2002

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tom 47

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nr 3

The common shrew Sorex araneus Linnaeus, 1758 is subject to intense chromosomal polymorphism. About 65 chromosome races are presently known. One of these chromosome races (the Valais race) is karyologically, morphologically, biochemically, and genetically clearly distinct from all other chromosome races of the species. Recent studies of hybrid zones between the Valais race and other chromosome races in the Swiss and French Alps add further strong evidence for the specific taxonomic status of the Valais race. Chromosomes and diagnostic protein markers reveal sharp frequency clines and strong heterozygote deficits. In one hybrid zone, the maintenance of the strong genetic differentiation of the hybridizing taxa was confirmed by a study with autosomal microsatellites indicating minimal gene flow. A microsatellite marker on the Y-chromosome showed complete absence of male mediated gene flow suggesting hybrid male sterility. To clarify the taxonomic status of this taxon, additional analyses were conducted. A morphometric analysis of the mandible indicated the Valais race is morphologically as distinct from neighbouring chromosome races of S. araneus as from other related Sorex species. In a phylogeny based on complete mitochondrial DNA cytochrome b gene sequences, the Valais race clearly appears as the sister taxon to all other races of S. araneus. Therefore, the chromosome race Valais of S. araneus herein is elevated to specific status and the name Sorex antinorii Bonaparte, 1840 is applied.

Ograniczanie wyników

Non-disjunction frequency in male complex Robertsonian heterozygotes of the common shrew

Morphometric difference between the Novosibirsk and Tomsk chromosome races of Sorex araneus in a zone of parapatry

A hybrid zone between the chromosomal races Legucki Mlyn and Popielno of the common shrew in North-Eastern Poland: preliminary results

Evolution of the common shrew Sorex araneus: chromosomal and molecular aspects

Maximization of the frequency of recombinants in the hybrid zones of Sorex araneus in northern Poland

A hybrid zone between the Kirillov and Petchora chromosomal races of the common shrew (Sorex araneus L., 1758) in northeastern European Russia: a preliminary description

Habitat use by Carrion Crows Corvus corone corone and Hooded Crows C. c. cornix and their hybrids in eastern Germany

The location of the Mus musculus-M.domesticus hybrid zone in the Balkans: clues from morphology

A taxonomical re-evaluation of the Valais chromosome race of the common shrew Sorex araneus [Insectivora: Soricidae]