Recurrent gene duplication in the angiosperm tribe Delphinieae (Ranunculaceae) inferred from intracellular gene transfer events and heteroplasmic mutations in the plastid matK gene.

The study of intracellular gene transfer may allow for the detection of interesting evolutionary processes such as ancient polyploidization. We compared 24 plastid genomes (plastomes) from tribe Delphinieae, one from tribe Nigelleae and one from tribe Ranunculeae, including five newly sequenced genomes. The functional transfers of the plastids rpl32 and rps16 to the nucleus in tribe Delphinieae were identified. Unexpectedly, we discovered multiple divergent copies of the nuclear-encoded plastid rpl32 in the genus Aconitum. Phylogenetic and synonymous substitution rate analyses revealed that the nuclear-encoded plastid rpl32 underwent two major duplication events. These ancient gene duplication events probably occurred via multiple polyploidization events in Aconitum between 11.9 and 24.7 Mya. Furthermore, our sequence rate analysis indicated that the eight plastid-encoded rpl subunits in Aconitum had a significantly accelerated evolutionary rate compared to those in other genera, suggesting that highly divergent paralogs targeted to the plastid may contribute to an elevated rate of evolution in plastid rpl genes. In addition, heteroplasmy of the plastid matK from two Aconitum species suggested the existence of potentially functional plastid maturases in its plastome. Our results provide insight into the evolutionary history of the tribe Delphinieae.

Ancient nigella seeds from Boyali Höyük in north-central Turkey.

AIM OF THE STUDY: The seeds of nigella (black cumin) (Nigella sativa L.) have been widely used as a natural remedy, either alone or in combination with bee products, for the treatment of many acute as well as chronic conditions for centuries, especially in the Middle East and Southeast Asia. In consideration of potential utilization, in recent years the seeds have been extensively studied in terms of pharmacological effects. It has been shown that the seeds have significant effects on multiple biological systems. In addition, the protective roles of the seeds with bee products (honey and wax) have been recently proved. This study reports the palaeoethnobotanical find of nigella seeds recovered in a pilgrim flask from the Old Hittite Period level of Boyali Höyük (Mound), dating from around 1650 BC, in north-central Turkey. The study also deals with a comparison between the chemical properties of the Boyali Höyük nigella seeds (ancient seeds) and those of modern nigella seeds. The results of chemical analysis of the debris found in the pilgrim flask to test the presence of bee product are also presented here. MATERIALS AND METHODS: All macro-remains found in the pilgrim flask were first examined under a zoom stereomicroscope for specific determination and all were identified as nigella seeds using the reference collection of modern seeds. Ethyl alcohol and dichloromethane (Aldrich, Buch-Switzerland) were used for the extraction of the ancient seeds and modern nigella seeds to trace both polar and non-polar chemical compounds by a Gas Chromatography-Mass Spectrometer (GC-MS) system. Characterization of the chemical compounds in propolis extracts was also made by GC-MS. RESULTS: The GC-MS chromatograms showed that the ancient and modern seed samples were similar in essential oil acids. Many organic compounds of bee products, such as wax and phenolic antioxidants, were also detected in the container. CONCLUSION: The results of this study indicated that the Hittite pilgrim flask contained a pure cache of nigella seeds mixed with bee products, wax and propolis. There has been no direct archaeological evidence for medicinal use of nigella seeds with bee products by the inhabitants of Boyali Höyük or the Hittities so far. However, in view of the folkloric use of nigella seeds in combination with bee products for treatments of disorders and promotion of health, it is thought that the Boyali Höyük material would represent a remedy used by the Hittites in Anatolia about 3600 years ago.