Am J Bot. 1998 Feb;85(2):162.
The mechanism of sex determination in dioecious species of the genus Atriplex (Chenopodiaceae) has not been determined. This paper reports the discovery of a male-specific DNA fragment in the diploid dioecious species A. garrettii. DNA samples extracted individually from ten male and ten female plants were bulked by sex. Random amplified polymorphic DNA (RAPD) fragments were generated in the two bulks in order to identify markers that were polymorphic between male and female plants. A total of 158 decamer primers were tested. A 2075 base-pair (bp) male-specific DNA fragment generated with the OPAF-14 primer was identified. The fragment was cloned and partially sequenced and 24-mer primers that exclusively amplified this fragment were constructed. When 124 male plants, 126 female plants, and one hermaphroditic plant were tested individually, the male-specific 2075-bp DNA fragment was present in the hermaphrodite and all but one of the male plants, and was absent in all female plants. A smaller DNA fragment (~1800 bp) that was homologous to the 2075-bp fragment was amplified from the single male plant that lacked the 2075-bp fragment. Cytogenetic analysis revealed no apparent heteromorphic sex chromosomes. These observations suggest that sex determination in A. garrettii is genetic, with no evidence of heteromorphic sex chromosomes.
雌雄异株的滨藜属（藜科）物种的性别决定机制尚不清楚。本文报道了在二倍体雌雄异株的滨藜属植物 A. garrettii 中发现一个雄性特异性的 DNA 片段。从 10 株雄性和 10 株雌性植物中分别提取的 DNA 样本按性别混合。在两个混合样本中生成随机扩增多态性 DNA（RAPD）片段，以鉴定在雄性和雌性植物之间具有多态性的标记。共测试了 158 个十聚体引物。用 OPAF-14 引物生成了一个 2075 碱基对（bp）的雄性特异性 DNA 片段。该片段被克隆并部分测序，并构建了专门扩增该片段的 24 聚体引物。当单独测试 124 株雄性植物、126 株雌性植物和 1 株雌雄同株植物时，雌雄同株和除一株雄性植物外的所有雄性植物中都存在雄性特异性的 2075-bp DNA 片段，而所有雌性植物中都不存在。从缺少 2075-bp 片段的单一雄性植物中扩增到与 2075-bp 片段同源的较小 DNA 片段（~1800bp）。细胞遗传学分析显示没有明显的异型性性染色体。这些观察结果表明，A. garrettii 的性别决定是遗传的，没有异型性性染色体的证据。
