Molecular and cytogenetic analysis of the telomeric (TTAGGG)n repetitive sequences in the Nile tilapia, Oreochromis niloticus (Teleostei: Cichlidae)
Molecular and cytogenetic analysis of the telomeric (TTAGGG)n repetitive sequences in the Nile tilapia, Oreochromis niloticus (Teleostei: Cichlidae)
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DOI：
10.1007/s00412-002-0187-3
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发表时间：
2002-03-01
期刊：
影响因子：
1.6
通讯作者：
Dobson, MJ
中科院分区：
文献类型：
--
作者：
Chew, JSK;Oliveira, C;Dobson, MJ
尼罗罗非鱼的大多数染色体，就像迄今为止大多数鱼类的核型一样，由于它们的尺寸很小，无法单独识别。作为建立罗非鱼这一重要水产养殖物种的物理图谱的第一步，我们分析了脊椎动物端粒重复序列(TTAGGG)(N)在尼罗罗非鱼中的位置。Southern杂交分析和Bal31敏感性分析证实，脊椎动物端粒重复序列确实存在于尼罗罗非鱼染色体末端，在红细胞的染色体末端有长达4-10kb的重复序列。荧光原位杂交显示，(TTAGGG)(N)不仅存在于端粒上，而且还存在于1号染色体的两个间隙部位。这些数据支持了1号染色体是由三条染色体融合而成的假说，并解释了罗非鱼的染色体数目从原始硬骨染色体的2n=48减少到2n=44。
The majority of chromosomes in Oreochromis niloticus, as with most fish karyotyped to date, cannot be individually identified owing to their small size. As a first step in establishing a physical map for this important aquaculture species of tilapia we have analyzed the location of the vertebrate telomeric repeat sequence, (TTAGGG)(n), in O. niloticus. Southern blot hybridization analysis and a Bal31 sensitivity assay confirm that the vertebrate telomeric repeat is indeed present at O. niloticus chromosomal ends with repeat tracts extending for 4-10 kb on chromosomal ends in erythrocytes. Fluorescent in situ hybridization revealed that (TTAGGG)(n) is found not only at telomeres, but also at two interstitial loci on chromosome 1. These data support the hypothesis that chromosome 1, which is significantly larger than all the other chromosomes in the karyotype, was produced by the fusion of three chromosomes and explain the overall reduction of chromosomal number from the ancestral teleost karyotype of 2n=48 to 2n=44 observed in tilapia.