Kuhn Gustavo C S, Franco Fernando F, Silva Wilson A, Martinez-Rossi Nilce M, Sene Fabio M
Faculdade de Medicina de Ribeirão Preto, Departamento de Genética, Universidade de São Paulo, Ribeirão Preto, Brazil.
Hereditas. 2003;139(3):161-6. doi: 10.1111/j.1601-5223.2003.01797.x.
The pBuM189 satellite DNA was analysed in Drosophila buzzatii populations that cover most of the species distribution in South America. This satDNA consists of A + T-rich monomers of 189 bp and previous studies showed a fast rate of evolutionary change of this component of D. buzzatii genome. A total of 63 pBuM189 repetition units from 14 D. buzzatii populations (9 from Brazil and 5 from Argentina) were studied. The average nucleotide variability among the 63 repeats is 4.2 %. At least one repeat (Juan/4) seems to be part of another pBuM189 satDNA subfamily. The nucleotide alignment of all 63 repeats revealed no specific nucleotide substitutions, or indels, that could discriminate each population or groups of geographically close populations. Such lack of satDNA interpopulational differentiation is congruent with previous mtDNA data that indicate a high gene flow and very little population differentiation throughout most of the D. buzzatii distribution in South America. Gene flow might have been possible during glaciation events in the Pleistocene, such as the one occurred between 13,000 and 18,000 years ago, when D. buzzatii probably had a more continuous distribution than what is observed today.
对分布于南美洲大部分地区的巴氏果蝇种群中的pBuM189卫星DNA进行了分析。这种卫星DNA由富含A + T的189 bp单体组成，先前的研究表明，巴氏果蝇基因组的这一组成部分进化变化速度很快。对来自14个巴氏果蝇种群（9个来自巴西，5个来自阿根廷）的总共63个pBuM189重复单元进行了研究。63个重复序列之间的平均核苷酸变异性为4.2%。至少有一个重复序列（Juan/4）似乎是另一个pBuM189卫星DNA亚家族的一部分。所有63个重复序列的核苷酸比对未发现可区分每个种群或地理上相邻种群组的特定核苷酸替换或插入缺失。卫星DNA种群间缺乏这种分化与先前的线粒体DNA数据一致，该数据表明，在南美洲巴氏果蝇分布的大部分地区，基因流较高，种群分化很小。在更新世的冰川事件期间，比如在13000至18000年前发生的那次冰川事件，基因流可能是有可能的，当时巴氏果蝇的分布可能比现在观察到的更加连续。
