Lambert B, Beermann W
Chromosoma. 1975;51(1):41-7. doi: 10.1007/BF00285806.
Cytogenetic analysis indicates that Balbiani Ring 2 (BR 2) in the two sibling species Chironomus tentans and Chironomus pallidivittatus arises from identifically banded segments in the salivary gland polytene chromosomes, although chromosomal rearrangements have occurred. In situ hybridization of BR 2 RNA to the polytene chromosomes of each individual species, as well as their F1 hybrids, reveals that the repetitious BR 2 DNA in the two species has, within the limits of the technique, retained identity of nucleotide sequences and degree of repetition. The DNA of the naturally expressed BR 1 and BR 3 in both species and that ot the galactose induced BR 6 in C. pallidivittatus did not hybridize with BR 2 RNA, indicating that these BR's are different from BR 2 with regard to sequence content.
细胞遗传学分析表明，在两种近缘物种——摇蚊（Chironomus tentans）和苍白摇蚊（Chironomus pallidivittatus）中，巴尔比亚尼环2（BR 2）源自唾液腺多线染色体中具有相同条带的片段，尽管已经发生了染色体重排。将BR 2 RNA与每个物种及其F1杂种的多线染色体进行原位杂交，结果显示，在该技术的检测范围内，两个物种中重复的BR 2 DNA在核苷酸序列和重复程度上保持一致。两个物种中天然表达的BR 1和BR 3的DNA，以及苍白摇蚊中半乳糖诱导的BR 6的DNA，均未与BR 2 RNA杂交，这表明这些BR在序列内容上与BR 2不同。
