The Chromosome Races of Sorex Araneus in Scandinavia

Abstract

The chromosomes were studied in 401 common shrews, Sorex araneus, from 91 localities in Scandinavia, the great majority in Sweden. Eight chromosome races were identified, each with its characteristic arm combination of metacentric chromosomes. Six races occur in Sweden and adjacent regions of Norway, and two in Denmark. The Swedish races are called, from north to south, Abisko, Sidensjö, Uppsala, Hällefors, Åkarp, and Öland, and the Danish races are called Sjaelland and Jutland. The geographic distribution of the races is described and discussed. Intrapopulation chromosome variation of Robertsonian type is common in the Abisko and Sidensjö, less common in the Uppsala and Öland, and absent in the Hällefors and Åkarp races. Polymorphism has not been demonstrated in the Danish races. All races but the Abisko race belong to the West European Karyotypic Group. The Abisko race is of eastern origin. The chromosome races in Denmark and Sweden form a series of whole arm reciprocal translocations with one exchange between adjacent races.

Reconstruction of the postglacial colonization of Sorex araneus into northern Scandinavia based on karyotype studies, and the subdivision of the Abisko race into three

“…1. These data are combined with previous investigations from northern Fennoscandia (Halkka et al, 1987(Halkka et al, , 1994Fredga, 1996Fredga, , 2003, and all data are presented in Tab. 2, which includes 257 specimens from 26 localities, 15 in Sweden, 8 in Norway and 3 in Finland.…”

“…Additional information: This race has previously been included in the Abisko race (Fredga, 1996;Zima et al, 1996).…”

“…However, published data include few specimens from the central part of this vast area, and as pointed out by Fredga (1996), it is impossible to decide whether these shrews belong to the Abisko or Savukoski races, because the arms g, m, o and r are unfused.…”

“…Up to now common shrews in northern Sweden have been regarded to belong to the same race, the Abisko race, covering an area from 63°30' N at the Gulf of Bothnia to 68°30' N at Abisko in the far northwest (Fredga, 1996). However, published data include few specimens from the central part of this vast area, and as pointed out by Fredga (1996), it is impossible to decide whether these shrews belong to the Abisko or Savukoski races, because the arms g, m, o and r are unfused.…”

Fertility assessment in hybrids between monobrachially homologous Rb races of the house mouse from the island of Madeira: implications for modes of chromosomal evolution

“…These conclusions can be extended to the other well-studied European Rb model organism, the common shrew (Sorex araneus), in which small meiotic chains or rings are known to have a remarkably low impact on the fertility of heterozygotes (Searle, 1993;Banaszek et al, 2000). In addition, WARTs have also been documented in this species (Fedyk and Chętnicki, 2009), and several authors have argued and recently tested their implication in shrew race formation (Fredga, 1996;Andersson et al, 2005). The relevance of WART events in chromosomal evolution has also been investigated in other mammalian taxa characterized by multiple Rb-type rearrangements.…”