Distinct geographic structure as evidenced by chloroplast DNA haplotypes and ploidy level in Japanese Aucuba (Aucubacea)
Distinct geographic structure as evidenced by chloroplast DNA haplotypes and ploidy level in Japanese Aucuba (Aucubacea)
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DOI：
10.3732/ajb.90.11.1645
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发表时间：
2003-11-01
影响因子：
3
通讯作者：
Murata, J
中科院分区：
文献类型：
--
作者：
Ohi, T;Kajita, T;Murata, J
对桃叶珊瑚的二倍体和四倍体细胞型以及cpDNA单倍型的地理分布进行了研究。我们使用流式细胞术测量相对基因组大小，并对两个cpDNA基因间区域atpB-rbcL和psbA-trnH（GUG）进行测序。两种单倍型包括二倍体和四倍体;其他四种都是四倍体。基于这些单倍型和细胞型的组合，可以定义八个“单倍型细胞型”，它们显示出独特的地理结构。在日本列岛的西南部分布有2个二倍体单倍型，东北部分布有6个四倍型。具有相同单倍型的二倍体和四倍体单倍型，在一种情况下，分离分布，在另一种情况下，接触。单倍型的系统发育关系表明，传统的A。日本是并系的。一个谱系由四倍体单倍型组成，另一个谱系由二倍体和四倍体单倍型加A. chinensis。四倍化独立发生至少三次，一次在前一谱系的基部，两次在后者。考虑到地理，细胞学和系统发育的证据，形成了目前的地理分化模式的单倍细胞型通过冰后期扩张从冰川避难所进行了讨论。
The geographic distribution of diploid and terraploid cytotypes and cpDNA haplotypes throughout the entire range of Aucuba japonica was investigated. We measured relative genome size using flow cytometry and sequenced two cpDNA intergenic regions, atpB-rbcL and psbA-trnH (GUG). Two haplotypes include both diploids and tetraploids; four others are all tetraploids. Based on the combination of these haplotypes and cytotypes, eight "hapio-cytotypes" can be defined, which show a distinct geographic structure. Two diploid haplo-cytotypes are distributed in the southwestern part and six tetraploid ones in the northeastern part of the Japanese archipelago. Diploid and tetraploid haplo-cytotypes with the same haplotype are, in one case, disjunctively distributed, and in another case, in contact. The phylogenetic relationships of haplo-cytotypes indicate that the traditional circumscription of A. japonica is paraphyletic. One lineage consists of four tetraploid haplo-cytotypes and another of diploid and tetraploid haplo-cytotypes plus A. chinensis. Tetraploidization occurred independently at least three times, once at the base of the former lineage and twice in the latter. Taking the geographic, cytological, and phylogenetic evidence into account, the formation of the present geographic differentiation pattern of haplo-cytotypes through postglacial expansion from glacial refugia is discussed.