In 1996 the International Sorex araneus Cytogenetics Committee (ISACC) published a comprehensive list of 50 chromosome races of the common shrew Sorex araneus (Zima et . 1996). Since that time twenty one new races have been described and three races have been removed from the list. The present list summarises the data about races described since the 1996 publication. The rules introduced by Searle et ai (1991) and Hausser et al (1994) were followed in the compilation of the list. It can be considered a reference for further studies of evolutionary relationships between the chromosome races of Sorex araneus. A summary table of all the 68 known races, arranged alphabetically according to their names, is given. RESUMEEn suivant les principes de nomenclature des chromosomes de Sorex araneus (Searle et al. 1991) et ceux de la definition de ses races chromosomiques , PISACC (International Sorex araneus Cytogenetics Committee) a public en 1996 la premiere liste de races chromosomiques de 5. araneus (Zima et al., 1996). Elle comprenait 50 races chromosomiques. Depuis, 21 race nouvelles ont etc decrites et trois races ont etc eliminees de cette liste. Nous presentons ici la liste revisee des races chromosomiques de 5. araneus qui comprend actuellement 68 races.

Two parapatric chromosomal races of the common shrew (Sorex araneus) in Poland differ in their complement of metacentric arm combinations: hk, io, gr, nm (race IV), and hi, ko, gm, np (race II). In hybrids, these eight race-diagnostic metacentrics form two randomly segregating complexes. The first complex (C ) occurs in the form of a ring configuration ok/kh/hi/io, or a chain o/ok/kh/hi/i (when there is Robertsonian polymorphism of the element io). The second complex (C ) always takes the form of a six-element chain configuration r/rg/gm/mn/np/p. The C complex may be shortened to five or even four elements, when acrocentrics g, m and n are present. In the contact zone we found shrews of pure races (race II or IV), as well as hybrids with C or C complexes, and recombinants hi, ko, gr, nm. Complex heterozygotes are likely to suffer reduced fertility due to malsegregation at meiosis. However, the C hybrids with ring configurations occur with a high frequency throughout the contact zone. This suggest that their fitness is only slightly lowered relative to pure race individuals, in contrast to the hybrids with C or C chain configurations, which presumably have a more heavily reduced fertility. On the other hand, at the center of the zone there is a high proportion of recombinants, which, being chromosomal homozygotes, should display normal meiotic segregation. Furthermore, the high frequencies of recombinants within the contact zone should facilitate gene flow between the races. The occurrence of recombinants plays a similar role as the appearance of the maximum frequencies of acrocentric homozygotes described in several contact zones of S. araneus.

The list of chromosome races of the common shrew (Sorex araneus) was compiled, the vast literature has been scrutinized, and unpublished data have been added. Altogether, 50 chromosome races could be listed. The name and its synonyms, chromosomal constitution, author of the description, type locality, known distribution range, and additional information are reported for individual races. The present list should be considered a working document that will be regularly updated and supplemented.

No abstract

Editorial comment. The common shrew, one of the characteristic small mammal species of Europe and neighbouring Asia, has for decades been a focus of cytogenetic investigation due to remarkable chromosome variation at an individual as well as at a population level. It is a fi ne example of long-term international collaboration through a scientifi c grouping founded in 1987 as the International Sorex araneus Cytogenetics Committee (ISACC). The cytogenetic characterisation of common shrews over the whole species range, from Britain in the west to the Lake Baikal in the east, was predicated on standard rules developed by the Committee. Thus, the basic nomenclature for Sorex araneus chromosomes and chromosome races was published in the proceedings of the second ISACC meeting held in Lausanne, Switzerland in 1990 and published in a local journal not available to many young people involved in chromosome studies of the species, in particular those based in Russia. The Editorial Board thanks Société vaudoise des Sciences Naturelles for permission to republish this paper here. Original: © Mém. Soc. Vaudoise Sci. Natur. 19: 13-22 (1991). Abstract.A G-band composite karyotype has been prepared for the common shrew (Sorex araneus Linnaeus, 1758). This includes multiple cut-outs of each chromosome arm (in different stages of contraction) derived from chromosome spreads prepared by a variety of methods by the different authors. The important features of each chromosome arm are described. The nomenclature for the chromosome arms follows that of Halkka et al. (1974) as clarifi ed by Fredga, Nawrin (1977) and subsequent authors, i.e. italicised letters of the alphabet are used with a as the largest chromosome arm. Different authors have used a variety of methods to describe the karyotype of (a) individuals and (b) the pattern of variation within populations. Also, defi nitions of chromosomal 'race' differ. We suggest a standardised scheme for the description of individuals, populations and chromosomal races.