Spence J M, Blackman R L, Testa J M, Ready P D
Department of Entomology, The Natural History Museum, London.
Chromosome Res. 1998 Apr;6(3):167-75. doi: 10.1023/a:1009251415941.
Numerous copies of a 169-base pair DNA sequence (Myzus persicae group repeat; MpR) occur at subtelomeric locations on all chromosomes of three members of the Myzus persicae species group (Myzus persicae, M. antirrhinii, M. certus). MpR occurs in large tandem arrays at both ends of all autosomes of the standard 2n = 12 karyotype, and near one end of the X chromosome (the end opposite to the nucleolar organizer) and is estimated to make up about 5% of the genome (a total of about 200000 copies). Locations of MpR were compared in various karyotypes to determine the likely nature of the rearrangements (fusions, dissociations, translocations) that are found in this species group which, like other Hemiptera, has holocentric chromosomes that are devoid of morphological markers. Aphid clones heterozygous for autosome dissociations do not have any detectable MpR at 'new' chromosome ends, indicating that this sequence is not involved in 'capping' of chromosomes. However, a clone with a de novo autosome fusion had an interstitial block of MpR marking the point of fusion, and clones heterozygous for an autosomal 1,3 translocation had MpR from autosome 1 translocated to a new site on autosome 3. The isolation from M. antirrhinii of the telomeric repeat TTAGG, which is found in several insect groups, is also reported.
169个碱基对的DNA序列（烟蚜组重复序列；MpR）的多个拷贝出现在烟蚜物种组三个成员（烟蚜、金鱼草蚜、确凿蚜）所有染色体的亚端粒位置。MpR以大串联阵列形式存在于标准2n = 12核型的所有常染色体两端，以及X染色体的一端附近（与核仁组织区相对的一端），估计占基因组的5%左右（总共约200000个拷贝）。在各种核型中比较了MpR的位置，以确定在该物种组中发现的重排（融合、解离、易位）的可能性质，该物种组与其他半翅目昆虫一样，具有无形态标记的全着丝粒染色体。常染色体解离杂合的蚜虫克隆在“新”染色体末端没有任何可检测到的MpR，这表明该序列不参与染色体的“加帽”。然而，一个具有从头常染色体融合的克隆有一个MpR的间质块标记融合点，常染色体1、3易位杂合的克隆有来自常染色体1的MpR易位到常染色体3的一个新位点。还报道了从金鱼草蚜中分离出端粒重复序列TTAGG，该序列在几个昆虫类群中都有发现。
