Hauffe Heidi C, Searle Jeremy B
Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK.
Evolution. 1993 Oct;47(5):1374-1395. doi: 10.1111/j.1558-5646.1993.tb02161.x.
The Robertsonian fusion is a common chromosomal mutation among mammal species and is especially prevalent in the West European house mouse, Mus musculus domesticus. More than 40 races of the house mouse exist in Europe, including the famous "tobacco mouse" (Poschiavo race) of Val Poschiavo, Switzerland. Documented here is the discovery of an extreme case of karyotypic variation in the neighboring Upper Valtellina, Italy. In a 20-km stretch of the valley, 32 karyotypes were observed, including five chromosomal races and 27 hybrid types. One previously unknown race is reported, the "Mid Valtellina" race, with a diploid number of 2n = 24 and the Robertsonian fusions Rb(1.3), Rb(4.6), Rb(5.15), Rb(7.18), Rb(8.12), Rb(9.14), Rb(11.13), and Rb(16.17). The Poschiavo race (2n = 26), Upper Valtellina race (2n = 24), Lower Valtellina race (2n = 22) and all-acrocentric race (2n = 40) were also present. The races form a patchy distribution, which we term a "mottled hybrid zone." Geographical position, isolation, extinction, recolonization, and selection against hybrids are all believed to be instrumental in the origin and evolution of this complex system. Previous studies of house mice from Upper Valtellina indicated that two of the races in the valley (the Upper Valtellina and Poschiavo races) may have speciated in the village of Migiondo. We discuss the possibility that there may have been a reinforcement event in this village.
罗伯逊融合是哺乳动物物种中常见的染色体突变，在西欧家鼠（小家鼠）中尤为普遍。欧洲存在40多个家鼠种群，包括瑞士瓦尔波斯基亚沃著名的“烟草鼠”（波斯基亚沃种群）。本文记录了在意大利邻近的上瓦尔泰利纳发现的一个核型变异的极端案例。在该山谷20公里的区域内，观察到32种核型，包括5个染色体种群和27种杂交类型。报告了一个先前未知的种群，即“中瓦尔泰利纳”种群，其二倍体数为2n = 24，具有罗伯逊融合Rb(1.3)、Rb(4.6)、Rb(5.15)、Rb(7.18)、Rb(8.12)、Rb(9.14)、Rb(11.13)和Rb(16.17)。波斯基亚沃种群（2n = 26）、上瓦尔泰利纳种群（2n = 24）、下瓦尔泰利纳种群（2n = 22）和全近端着丝粒种群（2n = 40）也存在。这些种群形成了斑驳的分布，我们称之为“斑驳杂交区”。地理位置、隔离、灭绝、重新定殖以及对杂交种的选择都被认为对这个复杂系统的起源和进化起到了作用。对上瓦尔泰利纳家鼠的先前研究表明，该山谷中的两个种群（上瓦尔泰利纳种群和波斯基亚沃种群）可能在米乔多村形成了物种分化。我们讨论了这个村庄可能发生强化事件的可能性。
