Insua Ana, López-Piñón María José, Freire Ruth, Méndez Josefina
Departamento de Biología Celular y Molecular, Universidade da Coruña, A Zapateira s/n, 15071, A Coruña, Spain.
Genetica. 2006 Mar;126(3):291-301. doi: 10.1007/s10709-005-7408-7.
This work describes the karyotype and chromosomal location of the ribosomal DNA (rDNA) of Pecten maximus and Mimachlamys varia, two commercial scallop species from Europe. According to the chromosome centromeric index values found, the karyotype of P. maximus is composed of 1 metacentric, 2 metacentric-submetacentric, 1 telocentric-subtelocentric and 15 telocentric pairs, and that of M. varia of 4 metacentric, 2 subtelocentric-submetacentric, 9 subtelocentric, 3 subtelocentric-telocentric and 1 telocentric-subtelocentric pairs. In P. maximus, 18S-28S rDNA was located by FISH on a metacentric-submetacentric pair, and in M. varia on a subtelocentric-submetacentric pair using both silver staining and FISH. PCR amplification of the 5S rDNA unit yielded a single product of about 460 bp (P. maximus) and 450 bp (M. varia), that used as probe revealed a 5S rDNA site on a telocentric pair in P. maximus and a subtelocentric pair in M. varia. Two-color FISH or sequential silver staining of 5S rDNA-FISH-metaphases corroborated that the two gene families are located on different chromosomes in both species. A comparative analysis of the data allowed the inference of karyotypic relationships within scallops.
这项研究描述了欧洲两种商业扇贝物种——大扇贝（Pecten maximus）和日本日月贝（Mimachlamys varia）的核型以及核糖体DNA（rDNA）的染色体定位。根据所发现的染色体着丝粒指数值，大扇贝的核型由1对中着丝粒染色体、2对中着丝粒 - 亚中着丝粒染色体、1对端着丝粒 - 亚端着丝粒染色体和15对端着丝粒染色体组成，而日本日月贝的核型由4对中着丝粒染色体、2对亚端着丝粒 - 亚中着丝粒染色体、9对亚端着丝粒染色体、3对亚端着丝粒 - 端着丝粒染色体和1对端着丝粒 - 亚端着丝粒染色体组成。在大扇贝中，通过荧光原位杂交（FISH）将18S - 28S rDNA定位在一对中着丝粒 - 亚中着丝粒染色体上，而在日本日月贝中，使用银染和FISH技术将其定位在一对亚端着丝粒 - 亚中着丝粒染色体上。5S rDNA单元的聚合酶链反应（PCR）扩增产生了一个约460 bp（大扇贝）和450 bp（日本日月贝）的单一产物，该产物用作探针时，在大扇贝的一对端着丝粒染色体上和日本日月贝的一对亚端着丝粒染色体上揭示了一个5S rDNA位点。5S rDNA - FISH中期相的双色FISH或连续银染证实，这两个基因家族在两种扇贝中都位于不同的染色体上。对这些数据的比较分析有助于推断扇贝内部的核型关系。
