Ehlers Bodil K, Maurice Sandrine, Bataillon Thomas
Department of Ecology and Genetics, University of Aarhus, Ny Munkegade, Building 540, 8000 Aarhus C, Denmark.
Proc Biol Sci. 2005 Sep 7;272(1574):1795-802. doi: 10.1098/rspb.2005.3168.
Gynodioecy is defined as the coexistence of two different sexual morphs in a population: females and hermaphrodites. This breeding system is found among many different families of angiosperms and is usually under nucleo-cytoplasmic inheritance, with maternally inherited genes causing male sterility and nuclear factors restoring male fertility. Numerous theoretical models have investigated the conditions for the stable coexistence of females and hermaphrodites. To date, all models rest on the assumption that restoration of a given male sterile genotype is controlled by a single Mendelian factor. Here, we review data bearing on the genetic determinism of sex inheritance in three gynodiecious plant species. We suggest that restoration of male fertility is probably best viewed as a quantitative trait controlled by many loci. We develop a threshold model that accommodates an underlying polygenic trait, which is resolved at the phenotypic level in discrete sexual morphs. We use this model to reanalyse data in Thymus vulgaris, Silene vulgaris and Plantago coronopus. A simple Mendelian inheritance of sex determinism is unlikely in all three species. We discuss how our model can shed additional light on the genetics of restoration and point towards future efforts in the modelling of gynodioecy.
雌性和雌雄同体。这种繁殖系统在许多不同的被子植物科中都有发现，通常受核质遗传控制，母系遗传的基因导致雄性不育，而核因子恢复雄性育性。众多理论模型研究了雌性和雌雄同体稳定共存的条件。迄今为止，所有模型都基于这样一个假设，即给定雄性不育基因型的恢复由单个孟德尔因子控制。在此，我们综述了有关三种雌雄异株植物性别遗传的遗传决定因素的数据。我们认为，雄性育性的恢复可能最好被视为一个由多个基因座控制的数量性状。我们开发了一个阈值模型，该模型适用于一个潜在的多基因性状，该性状在表型水平上表现为离散的性形态。我们用这个模型重新分析了百里香、普通麦瓶草和海滨车前的数据。在这三个物种中，性别决定不太可能是简单的孟德尔遗传。我们讨论了我们的模型如何能够进一步阐明育性恢复的遗传学，并指出未来在雌雄异株建模方面的努力方向。
