Inferences of evolutionary relationships from a population survey of LTR-retrotransposons and telomeric-associated sequences in the Saccharomyces sensu stricto complex
Inferences of evolutionary relationships from a population survey of LTR-retrotransposons and telomeric-associated sequences in the Saccharomyces sensu stricto complex
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作者：
Liti, G;Peruffo, A;Louis, EJ
Saccharomyces sensu stricto 复合体由六种密切相关的物种和一种自然杂交种组成。重复元素的种内和种间变异可以帮助阐明这些近亲的种群结构和进化。已使用 PFGE 在 112 个分离株中确定了几个端粒相关序列 (TAS) 和 LTR 逆转录转座子的染色体位置。大多数研究的重复元件在每个菌株中都有多个拷贝，尽管在某些亚群中这些元件以低拷贝数存在或不存在。重复元件的杂交模式和拷贝数与地理分布相关。这些模式可能会为一些 TAS 和反转录转座子的起源和进化提供有趣的线索，例如我们可以推断Y'起源于XIV染色体的左端。有强有力的证据表明 Ty2 在酿酒酵母和 S. mikatae 之间水平转移。 Ty1和Ty5要么容易丢失，要么经常水平转移。我们还在物种内的分离株和物种间的一些新的自然杂交体中发现了一些严重的染色体重排，表明这些过程发生在野外，并且不限于人类影响的条件。 DNA 序列已存入 EMBL/GenBank 数据库，登录号为 AJ632279-AJ632293。版权所有 (C) 2005 John Wiley Sons, Ltd.
The Saccharomyces sensu stricto complex consists of six closely related species and I one natural hybrid. Intra- and inter-species variability in repetitive elements can help elucidate the population structure and evolution of these close relatives. The chromosome positions of several telomeric associated sequences (TASs) and LTR-retrotransposons have been determined, using PFGE, in 112 isolates. Most of the repetitive elements studied are found in multiple copies in each strain, although in some subpopulations these elements are present in low copy number or are absent. Hybridization patterns and copy numbers of the repetitive elements correlate with geographic distribution. These patterns may yield interesting clues as to the origins and evolution of some TASs and retrotransposons, e.g. we can infer that Y' originated on the left end of chromosome XIV. There is strong evidence for horizontal transfer of Ty2 between S. cerevisiae and S. mikatae. Ty1 and Ty5 are either lost easily or frequently horizontally transferred. We have also found some gross chromosomal rearrangements in isolates within species and a few new natural hybrids between species, indicating that these processes occur in the wild and are not limited to conditions of human influence. DNA sequences have been deposited with the EMBL/GenBank database under Accession Nos AJ632279-AJ632293. Copyright (C) 2005 John Wiley Sons, Ltd.