Inversion length and breakpoint distribution in the Drosophila buzzatii species complex: Is inversion length a selected trait?
Inversion length and breakpoint distribution in the Drosophila buzzatii species complex: Is inversion length a selected trait?
复制标题
DOI：
10.1111/j.1558-5646.1997.tb03962.x
复制
发表时间：
1997-08-01
期刊：
影响因子：
3.3
通讯作者：
Ruiz, A
中科院分区：
文献类型：
--
作者：
Caceres, M;Barbadilla, A;Ruiz, A
断裂点的长度和位置是倒位的特征，可以在果蝇物种的多线染色体上精确地确定，它们提供了关于控制倒位起源和进化的过程的关键信息。在果蝇种复合体中发现了86个近着丝粒倒位，在果蝇种内发现了18个由渐渗杂交引起的倒位。buzzatii进行了分析。与以往的研究相比，反转长度和断点分布被同时考虑。我们的结论是：（1）倒位长度是一个选择性性状，罕见的倒位以小倒位为主，而在进化上成功的多型和固定倒位以中等倒位为主，在不成功和成功的倒位之间，倒位长度从小到中等几乎是连续变化的;（2）倒位长度与多态性倒位数之间存在显著的负相关，可解释倒位长度变异的39%;（3）倒位长度的自然选择似乎是决定断裂点沿着染色体的相对位置的主要因素;（4）断裂点根据其条带位置的分布是非随机的，染色体片段累积多达8个断裂点。
Length and position of breakpoints are characteristics of inversions that can be precisely determined on the polytene chromosomes of Drosophila species, and they provide crucial information about the processes that govern the origin and evolution of inversions. Eighty-six paracentric inversions described in the Drosophila buzzatii species complex and 18 inversions induced by introgressive hybridization in D. buzzatii were analyzed. In contrast to previous studies, inversion length and breakpoint distribution have been considered simultaneously. We conclude that: (1) inversion length is a selected trait; rare inversions are predominantly small while evolutionarily successful inversions, polymorphic and fixed, are predominantly intermediate in length; a nearly continuous variation in length, from small to medium sized, is found between less and more successful inversions; (2) there exists a significant negative correlation between length and number of polymorphic inversions per species which explains 39% of the inversion length variance; (3) natural selection on inversion length seems the main factor determining the relative position of breakpoints along the chromosomes; (4) the distribution of breakpoints according to their band location is non-random, with chromosomal segments that accumulate up to eight breakpoints.