| Abstrakt: |
In the vicinity of John o’Groats (Caithness, Scotland) there is a small karyotypic race of the house mouse (Mus musculus domesticus) characterized by a diploid number of 32 chromosomes, including the metacentries 4.10, 9.12, 6.13 and 11.14. This race forms a hybrid zone with the standard British race (fully acrocentric chromosomes, 2n= 40). Although hybrid zones normally consist of several (or many) narrow character dines at the same position, this zone is unusual in that the chromosomal cines do not coincide. The dine for arm combination 11.14 is staggered relative to the 6.13 dine and both are separate from the clines for 4.10 and 9.12 (which may or may not coincide). A variety of explanations for the structure of the hybrid zone are discussed. It is possible that this may be a case of ‘zonal raciation’. |
