Solovei I, Ogawa A, Naito M, Mizuno S, Macgregor H
Institute of Anthropology and Human Genetics, LMU, München, Germany.
Chromosome Res. 1998 Jun;6(4):323-7. doi: 10.1023/a:1009279025959.
Chromomeres 1 and 3 of the chicken W lampbrush chromosome contain most of the EcoRI and XhoI repeat sequence families respectively. These chromomeres were stained with DAPI and their sizes relative to other W chromomeres were observed. Their relative contents of EcoRI and XhoI repeats were determined using fluorescence in situ hybridization with genomic probes for each of the two repeat families. There were two types of W chromosome in the chickens (White Leghorn and Rhode Island Red) used in this study with respect to the amount of EcoRI repeat. A high-copy-number type has about 4000 copies of the 1.2-kb repeat per genome and shows a large fluorescence signal on W chromomere 1. A low-copy-number type has about 700 copies per genome and does not have a detectable chromomere 1 on W chromosome, nor does it show FISH labelling in the region normally occupied by chromomere 1. The genome of Fayoumi chickens has about one-sixth the amount of the XhoI sequence family of White Leghorns. W lampbrush chromomere 3 is much smaller and its FISH labelling with the XhoI probe is much weaker in Fayoumis than in White Leghorns. These results demonstrate that in the chicken W chromosome, specific chomomeres are occupied by specific DNA repeat sequence families.
鸡W灯刷染色体的染色粒1和3分别包含大部分EcoRI和XhoI重复序列家族。这些染色粒用DAPI染色，并观察它们相对于其他W染色粒的大小。使用针对两个重复家族中每个家族的基因组探针进行荧光原位杂交，确定它们的EcoRI和XhoI重复序列的相对含量。在本研究中使用的鸡（白来航鸡和罗德岛红鸡）中，就EcoRI重复序列的数量而言，有两种类型的W染色体。高拷贝数类型每个基因组约有4000个1.2 kb重复序列的拷贝，在W染色粒1上显示出大的荧光信号。低拷贝数类型每个基因组约有700个拷贝，在W染色体上没有可检测到的染色粒1，在通常由染色粒1占据的区域也没有显示FISH标记。法尤米鸡的基因组中XhoI序列家族的数量约为白来航鸡的六分之一。在法尤米鸡中，W灯刷染色粒3要小得多，并且用XhoI探针进行的FISH标记比在白来航鸡中弱得多。这些结果表明，在鸡的W染色体中，特定的染色粒被特定的DNA重复序列家族占据。
