GENETIC EVIDENCE FOR MULTIPLE ORIGINS OF DIOECY IN THE HAWAIIAN SHRUB WIKSTROEMIA (THYMELAEACEAE)
GENETIC EVIDENCE FOR MULTIPLE ORIGINS OF DIOECY IN THE HAWAIIAN SHRUB WIKSTROEMIA (THYMELAEACEAE)
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夏威夷灌木威克斯特罗米亚（百里香科）雌雄异株的多种起源的遗传证据
DOI：
10.1111/j.1558-5646.1992.tb01995.x
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发表时间：
1992
期刊：
影响因子：
3.3
通讯作者：
D. Charlesworth
中科院分区：
文献类型：
--
作者：
S. Mayer;D. Charlesworth
雌雄异体在夏威夷群岛非常常见，但人们对这种繁殖系统的进化生物学知之甚少。本土灌木 Wikstroemia 具有异常多样化的繁殖系统：两种形式的雌雄异株，隐性雌雄异体和形态雌雄异株，以及雌雄同体（完美的花朵）。两种形式的雌雄同体的存在具有重要意义，原因有以下三个：1）功能上单性的神秘单性动物的存在，但在两性中都保留了雌雄同体的外观，这是雌雄同体祖先地位的有力证据； 2）雌性神秘单性动物产生无功能的花粉，是先前在其他一些物种中报道过的现象的一个新实例； 3）雌雄异体的两种形式是形态学标记，可用于杂交研究，以追踪其遗传的遗传基础。在神秘的单性个体之间（C）、形态上的单性个体之间（M）以及两种类型的单性个体之间进行杂交。具有相同性别类型的个体之间的杂交后代通常会产生具有该性别类型的后代，但出乎意料的是，大多数性别类型之间杂交的后代是完美开花的雌雄同体。这些结果表明，性别决定的遗传控制在所有种群中并不是同源的，这表明雌雄异体在夏威夷威克斯特罗米亚中至少进化了两次。遗传数据进一步表明男性是杂合性别。
Dioecy is unusually common in the Hawaiian Islands, yet little is known about the evolutionary biology of this breeding system. A native shrub, Wikstroemia, has an unusually diverse array of breeding systems: two forms of dioecy, cryptic and morphological dioecy, as well as hermaphroditism (perfect flowers). The existence of two forms of dioecy is significant for three reasons: 1) the presence of cryptic unisexuals that are functionally unisexual, but retain the appearance of hermaphroditism in both sexes, is strong evidence for the ancestral status of hermaphroditism; 2) the production of nonfunctional pollen, by female cryptic unisexuals, is a new instance of a phenomenon which has previously been reported for a few other species; 3) the two forms of dioecy are morphological markers which are useful in hybridization studies for tracing the genetic basis of their inheritance. Crosses were made between cryptically unisexual individuals (C), between morphologically unisexual individuals (M), and between the two types of unisexuality. The offspring of crosses between individuals with the same sex type usually resulted in offspring with that sex type, but most of the progeny of between‐sex type crosses were, unexpectedly, perfect‐flowered hermaphrodites. These results show that genetic control of sex determination is not homologous in all populations, suggesting that dioecy has evolved at least twice in Hawaiian Wikstroemia. The genetic data further suggest that males are the heterozygous sex.