Case S T, Summers R L, Jones A G
Cell. 1983 Jun;33(2):555-62. doi: 10.1016/0092-8674(83)90436-1.
pCtBR2-2 is a genomic clone from Chironomus tentans that hybridized in situ to Balbiani ring 2 (BR2) on salivary gland polytene chromosome IV. DNA sequencing indicated that the insert contained nearly four copies of a 180 bp tandemly repeated nucleotide sequence that was distinctly different from a previously reported BR2 repeat. Sequence titration experiments detected about 70 copies of the 180 bp repeat per haploid genome, which would correspond to approximately 34% of a 37 kb BR2 gene. Each 180 bp repeat included a conserved 90 bp segment whose sequence was internally nonrepeating (INR), and a variable 90 bp repeated (R) segment comprised of three 30 bp repeats that may have evolved from a 9 bp consensus sequence. Results presented here raise the distinct possibility that other BR genes may contain significantly different repeated sequences that have not been identified.
pCtBR2 - 2是来自摇蚊的一个基因组克隆，它在唾液腺多线染色体IV上与巴尔比亚尼环2（BR2）进行原位杂交。DNA测序表明，插入片段包含近四个180 bp串联重复核苷酸序列的拷贝，该序列与先前报道的BR2重复序列明显不同。序列滴定实验检测到每个单倍体基因组约有70个180 bp重复序列拷贝，这相当于37 kb BR2基因的约34%。每个180 bp重复序列包括一个保守的90 bp片段，其序列内部无重复（INR），以及一个可变的90 bp重复（R）片段，由三个30 bp重复序列组成，可能从一个9 bp共有序列进化而来。此处给出的结果显著增加了其他BR基因可能包含尚未被鉴定的明显不同的重复序列的可能性。
