Kuroiwa A, Terai Y, Kobayashi N, Yoshida K, Suzuki M, Nakanishi A, Matsuda Y, Watanabe M, Okada N
Laboratory of Animal Cytogenetics, Faculty of Science, Hokkaido University, Sapporo, Japan.
Cytogenet Genome Res. 2014;142(2):112-20. doi: 10.1159/000356128. Epub 2013 Nov 8.
Cichlid fishes in the African Great Lakes are known as a spectacular example of adaptive radiation in vertebrates. Four linkage maps have been constructed to identify the genes responsible for adaptation and speciation, and the genetic linkages of those genes are assumed to play an important role during adaptive evolution. However, it is difficult to analyze such linkages because the linkage groups of one species do not match well with those of the other species. Chromosome markers are a powerful tool for the direct identification of linkage homology between different species. We used information about the linkage map of the Lake Malawi cichlid (Labeotropheus fuelleborni/Metriaclima zebra) to isolate bacterial artificial chromosome (BAC) clones from the BAC library of Paralabidochromis chilotes, Lake Victoria. We identified 18 of 22 P. chilotes chromosomes by single- and multi-color BAC fluorescence in situ hybridization using 19 BAC clones. Comparative mapping with the chromosome markers of P. chilotes in Astatotilapia burtoni (2n = 40) from Lake Tanganyika revealed the chromosome rearrangements that have occurred in this lineage. These chromosome markers will be useful for delineating the process of genome and chromosome evolution in African species.
非洲大湖中的丽鱼科鱼类是脊椎动物适应性辐射的一个显著例子。已经构建了四张连锁图谱来确定负责适应和物种形成的基因，并且这些基因的遗传连锁被认为在适应性进化过程中发挥重要作用。然而，由于一个物种的连锁群与其他物种的连锁群不太匹配，因此很难分析这种连锁关系。染色体标记是直接鉴定不同物种间连锁同源性的有力工具。我们利用马拉维湖丽鱼（富氏新亮丽鲷/斑马拟丽鱼）连锁图谱的信息，从维多利亚湖奇氏副丽鱼的细菌人工染色体（BAC）文库中分离BAC克隆。我们使用19个BAC克隆，通过单双色BAC荧光原位杂交鉴定了奇氏副丽鱼22条染色体中的18条。与坦噶尼喀湖伯氏非鲫（2n = 40）的奇氏副丽鱼染色体标记进行比较作图，揭示了该谱系中发生的染色体重排。这些染色体标记将有助于描绘非洲物种的基因组和染色体进化过程。
