Hashimoto D T, Ferguson-Smith M A, Rens W, Foresti F, Porto-Foresti F
Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista (UNESP), Bauru, Brazil.
Cytogenet Genome Res. 2011;134(1):64-71. doi: 10.1159/000323512. Epub 2011 Jan 19.
We report here on the physical mapping of the H1 histone genes (hisDNA) and the 5S ribosomal DNA (rDNA) in 3 Neotropical fish species of the genus Astyanax(A. altiparanae, A. bockmanni and A. fasciatus) and the comparative analysis of the chromosomes bearing these genes. Nucleotide analyses by sequencing of both genes were also performed. The distribution of the H1 histone genes was more conserved than that of the rRNA genes, since these were always located in the pericentromeric regions of 2 chromosome pairs. 5S rDNA was found on one of the pairs that presented an H1 histone cluster; this seems to be a conserved chromosomal feature of the genus Astyanax. In addition, individuals of A. bockmanni and A. fasciatus showed clusters of 5S rDNA on 1 pair of acrocentric chromosomes, not found in A. altiparanae. The results obtained by chromosome mapping as well as by sequencing of both genes showed that A.bockmanni is more closely related to A. fasciatus than to A. altiparanae. The results allow the characterization of cytogenetic markers for improved elucidation of the processes involved in karyotype differentiation of fish genomes.
我们在此报告了对新热带地区丽脂鲤属（Astyanax）的3种鱼类（高身丽脂鲤、博氏丽脂鲤和条纹丽脂鲤）中H1组蛋白基因（hisDNA）和5S核糖体DNA（rDNA）的物理图谱绘制，以及对携带这些基因的染色体的比较分析。我们还对这两个基因进行了测序的核苷酸分析。H1组蛋白基因的分布比rRNA基因更为保守，因为这些基因总是位于两对染色体的着丝粒周围区域。在呈现H1组蛋白簇的其中一对染色体上发现了5S rDNA；这似乎是丽脂鲤属的一个保守染色体特征。此外，博氏丽脂鲤和条纹丽脂鲤的个体在一对近端着丝粒染色体上显示出5S rDNA簇，而高身丽脂鲤中未发现。通过染色体图谱绘制以及对这两个基因的测序所获得的结果表明，博氏丽脂鲤与条纹丽脂鲤的亲缘关系比与高身丽脂鲤的更近。这些结果有助于对细胞遗传学标记进行表征，以更好地阐明鱼类基因组核型分化过程中所涉及的过程。
