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Domesticated grapevines spread to Europe around 3,000 years ago. Previous studies have revealed genomic signals of introgression from wild to cultivated grapes in Europe, but the time, mode, genomic pattern, and biological effects of these introgression events have not been investigated. Here, we studied resequencing data from 345 samples spanning the distributional range of wild (Vitis viniferassp.sylvestris) and cultivated (V. viniferassp.vinifera) grapes. Based on machine learning–based population genetic analyses, we detected evidence for a single domestication of grapevine, followed by continuous gene flow between European wild grapes (EU) and cultivated grapes over the past ~2,000 y, especially from EU to wine grapes. We also inferred that soft-selective sweeps were the dominant signals of artificial selection. Gene pathways associated with the synthesis of aromatic compounds were enriched in regions that were both selected and introgressed, suggesting EU wild grapes were an important resource for improving the flavor of cultivated grapes. Despite the potential benefits of introgression in grape improvement, the introgressed fragments introduced a higher deleterious burden, with most deleterious SNPs and structural variants hidden in a heterozygous state. Cultivated wine grapes have benefited from adaptive introgression with wild grapes, but introgression has also increased the genetic load. In general, our study of beneficial and harmful effects of introgression is critical for genomic breeding of grapevine to take advantage of wild resources. 

Summary Biological invasions offer model systems of contemporary evolution. We examined trait differences and evolution across geographic clines among continents of the intertidal grassSpartina alterniflorawithin its invasive and native ranges.We sampled vegetative and reproductive traits in the field at 20 sites over 20° latitude in China (invasive range) and 28 sites over 17° in the US (native range). We grew both Chinese and US plants in a glasshouse common garden for 3 yr.Chinese plants werec. 15% taller,c. 10% denser, and set up to four times more seed than US plants in both the field and common garden. The common garden experiments showed a striking genetic cline of seven‐fold greater seed set at higher latitudes in the introduced but not the native range. By contrast, there was a slight genetic cline in some vegetative traits in the native but not the introduced range.Our results are consistent with others showing that introduced plants can evolve rapidly in the new range.S. alterniflorahas evolved different trait clines in the native and introduced ranges, showing the importance of phenotypic plasticity and genetic control of change during the invasion process. 

Abstract Introduced plants provide a unique opportunity to examine how plants respond through plasticity and adaptation to changing climates. We compared plants ofSpartina alterniflorafrom the native (United States, 27–43°N) and introduced (China, 19–40°N) ranges. In the field and greenhouse, aboveground productivity of Chinese plants was greater than that of North American plants. Aboveground biomass in the field declined with increasing latitude in the native range, a pattern that persisted in the greenhouse, indicating a genetic basis. Aboveground biomass in the field displayed hump‐shaped relationships with latitude in China, but this pattern disappeared in field and greenhouse common gardens, indicating phenotypic plasticity. Relationships in both geographic regions were explained by temperature, which is probably the underlying environmental factor affecting aboveground biomass.S. alterniflorahas evolved greater biomass in China, but in the four decades since it was introduced, it has not yet evolved the genetic cline in biomass seen in its native range. By working at lower latitudes in the introduced range than have been sampled in the native range, we identified an optimum temperature in the introduced range above which aboveground productivity decreases.