CESAM - Centro de Estudos do Ambiente e do Mar, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal.
Departamento de Biologia, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
Genes (Basel). 2020 Jul 6;11(7):748. doi: 10.3390/genes11070748.
Analysis of contact zones between parapatric chromosomal races can help our understanding of chromosomal divergence and its influence on the speciation process. Monitoring the position and any movement of contact zones can allow particular insights. This study investigates the present (2012-2014) and past (1998-2002) distribution of two parapatric house mouse chromosomal races-PEDC (Estreito da Calheta) and PADC (Achadas da Cruz)-on Madeira Island, aiming to identify changes in the location and width of their contact. We also extended the 1998-2002 sampling area into the range of another chromosomal race-PLDB (Lugar de Baixo). Clinal analysis indicates no major geographic alterations in the distribution and chromosomal characteristics of the PEDC and PADC races but exhibited a significant shift in position of the Rb (7.15) fusion, resulting in the narrowing of the contact zone over a 10+ year period. We discuss how this long-lasting contact zone highlights the role of landscape on mouse movements, in turn influencing the chromosomal characteristics of populations. The expansion of the sampling area revealed new chromosomal features in the north and a new contact zone in the southern range involving the PEDC and PLDB races. We discuss how different interacting mechanisms (landscape resistance, behaviour, chromosomal incompatibilities, meiotic drive) may help to explain the pattern of chromosomal variation at these contacts between chromosomal races.
分析毗邻分布的染色体重组区有助于我们理解染色体重组及其对物种形成过程的影响。监测接触区的位置和任何移动都可以提供特定的见解。本研究调查了两个毗邻的小家鼠染色体亚种-PEDC（Estreito da Calheta）和 PADC（Achadas da Cruz）-在马德拉岛的现今（2012-2014 年）和过去（1998-2002 年）的分布情况，旨在确定其接触区位置和宽度的变化。我们还将 1998-2002 年的采样区域扩展到另一个染色体亚种-PLDB（Lugar de Baixo）的范围内。渐变分析表明，PEDC 和 PADC 亚种的分布和染色体特征没有重大的地理变化，但 Rb（7.15）融合的位置发生了显著变化，导致接触区在 10 多年的时间里变窄。我们讨论了这种长期存在的接触区如何突出了景观对老鼠运动的影响，进而影响了种群的染色体特征。采样区域的扩大揭示了北部的新染色体特征和南部范围内涉及 PEDC 和 PLDB 亚种的新接触区。我们讨论了不同的相互作用机制（景观阻力、行为、染色体不相容性、减数分裂驱动）如何有助于解释这些染色体亚种之间的染色体变异模式。
