Groh Jeffrey S, Vik Diane C, Davis Matthew, Monroe J Grey, Stevens Kristian A, Brown Patrick J, Langley Charles H, Coop Graham
Department of Evolution and Ecology, University of California, Davis, CA, USA.
Center for Population Biology, University of California, Davis, CA, USA.
Science. 2025 Jan 3;387(6729):eado5578. doi: 10.1126/science.ado5578.
Balanced mating type polymorphisms offer a distinct window into the forces shaping sexual reproduction strategies. Multiple hermaphroditic genera in Juglandaceae, including walnuts () and hickories (), show a 1:1 genetic dimorphism for male versus female flowering order (heterodichogamy). We map two distinct Mendelian inheritance mechanisms to ancient (>37 million years old) genus-wide structural DNA polymorphisms. The dominant haplotype for female-first flowering in contains tandem repeats of the 3' untranslated region of a gene putatively involved in trehalose-6-phosphate metabolism and is associated with increased gene expression in developing male flowers, possibly mediated by small RNAs. The locus contains ~20 syntenic genes and shows molecular signatures of sex chromosome-like evolution. Inheritance mechanisms for heterodichogamy are deeply conserved, yet may occasionally turn over, as in sex determination.
平衡的交配型多态性为了解塑造有性生殖策略的力量提供了一个独特的窗口。胡桃科的多个雌雄同体属，包括核桃（）和山核桃（），在雄花与雌花开花顺序上呈现1:1的遗传二态性（异花受精）。我们将两种不同的孟德尔遗传机制映射到古老的（超过3700万年）全属范围的结构DNA多态性上。核桃中雌花先开的显性单倍型包含一个可能参与海藻糖-6-磷酸代谢的基因3'非翻译区的串联重复序列，并且与发育中的雄花中基因表达增加相关，可能由小RNA介导。位点包含约20个同线基因，并显示出类似性染色体进化的分子特征。异花受精的遗传机制高度保守，但偶尔也可能像性别决定那样发生转变。
