Mariotti Beatrice, Navajas-Pérez Rafael, Lozano Rafael, Parker John S, de la Herrán Roberto, Rejón Carmelo Ruiz, Rejón Manuel Ruiz, Garrido-Ramos Manuel, Jamilena Manuel
Departamento de Biología Aplicada, Escuela Politécnica Superior, Universidad de Almería, 04120 Almería, Spain.
Genome. 2006 Feb;49(2):114-21. doi: 10.1139/g05-089.
Rumex acetosa is characterized by a multiple chromosome system (2n = 12 + XX for females, and 2n = 12 + XY1Y2 for males), in which sex is determined by the ratio between the number of X chromosomes and autosome sets. For a better understanding of the molecular structure and evolution of plant sex chromosomes, we have generated a sex chromosome specific library of R. acetosa by microdissection. The screening of this library has allowed us to identify 5 repetitive DNA families that have been characterized in detail. One of these families, DOP-20, has shown no homology with other sequences in databases. Nevertheless, the putative proteins encoded by the other 4 families, DOP-8, DOP-47, DOP-60, and DOP-61, show homology with proteins from different plant retroelements, including poly proteins from Ty3-gypsy- and Ty1-copia-like long terminal repeat (LTR) retroelements, and reverse transcriptase from non-LTR retro elements. Results indicate that sequences from these 5 families are dispersed throughout the genome of both males and females, but no appreciable accumulation or differentiation of these types of sequences have been found in the Y chromosomes. These repetitive DNA sequences are more conserved in the genome of other dioecious species such as Rumex papillaris, Rumex intermedius, Rumex thyrsoides, Rumex hastatulus, and Rumex suffruticosus, than in the polygamous, gynodioecious, or hermaphrodite species Rumex induratus, Rumex lunaria, Rumex con glom er atus, Rumex crispus, and Rumex bucephalo phorus, which supports a single origin of dioecious species in this genus. The implication of these transposable elements in the origin and evolution of the heteromorphic sex chromosomes of R. acetosa is discussed.
酸模具有多染色体系统（雌性为2n = 12 + XX，雄性为2n = 12 + XY1Y2），其中性别由X染色体数量与常染色体组数量的比例决定。为了更好地理解植物性染色体的分子结构和进化，我们通过显微切割构建了酸模的性染色体特异性文库。对该文库的筛选使我们能够鉴定出5个已详细表征的重复DNA家族。其中一个家族DOP - 20与数据库中的其他序列没有同源性。然而，其他4个家族DOP - 8、DOP - 47、DOP - 60和DOP - 61编码的推定蛋白质与来自不同植物反转录元件的蛋白质具有同源性，包括来自Ty3 - gypsy - 和Ty1 - copia - 样长末端重复（LTR）反转录元件的多蛋白，以及来自非LTR反转录元件的逆转录酶。结果表明，这5个家族的序列分散在雄性和雌性的整个基因组中，但在Y染色体上未发现这些类型序列的明显积累或分化。这些重复DNA序列在其他雌雄异株物种如乳头酸模、中间酸模、圆锥酸模、戟叶酸模和半灌木酸模的基因组中比在多配性、雌全异株或雌雄同体物种硬果酸模、月状酸模、聚生酸模、皱叶酸模和牛头酸模中更保守，这支持了该属中雌雄异株物种的单一起源。本文讨论了这些转座元件在酸模异形性染色体起源和进化中的意义。
