Chaotic genetic patchiness （CGP） refers to surprising patterns of spatial and temporal genetic structure observed in some marine species at a scale where genetic variation should be efficiently homogenized by gene f...Chaotic genetic patchiness （CGP） refers to surprising patterns of spatial and temporal genetic structure observed in some marine species at a scale where genetic variation should be efficiently homogenized by gene flow via larval dispersal. Here we review and discuss 4 mechanisms that could generate such unexpected patterns： selection, sweepstakes reproductive success, collective dispersal, and temporal shifts in local population dynamics. First, we review examples where genetic differentiation at specific loci was driven by diversifying selection, which was historically the first process invoked to explain CGP. Second, we turn to neutral demographic processes that may drive genome-wide effects, and whose effects on CGP may be enhanced when they act together. We discuss how sweepstakes reproductive success accelerates genetic drift and can thus generate genetic structure, provided that gene flow is not too strong. Collective dispersal is another mechanism whereby genetic structure can be maintained regardless of dispersal intensity, because it may prevent larval cohorts from becoming entirely mixed. Theoretical analyses of both the sweepstakes and the collective dispersal ideas are presented. Finally, we discuss an idea that has received less attention than the other ones just mentioned, namely temporal shifts in local population dynamics.展开更多
Zhao Yingcheng （1619-1657）, known as ＂The Great Advisor＂, is the only Kaifeng Jew who is mentioned both in the synagogal stele of 1663 and in Chinese gazetteers during his lifetime. Zhao, given the Hebrew name of ...Zhao Yingcheng （1619-1657）, known as ＂The Great Advisor＂, is the only Kaifeng Jew who is mentioned both in the synagogal stele of 1663 and in Chinese gazetteers during his lifetime. Zhao, given the Hebrew name of Moshe ben Avram, was fluent in Hebrew but also achieved success as a Confucian scholar familiar with the Chinese classics. He would have witnessed the destruction of his hometown by a catastrophic flood during the 1642 Siege of Kaifeng. In 1645, at the age of 26, he attained the jinshi rank in the Imperial Exams, in which only one in 10,000 can- didates was successful. A year later, he was appointed Minister of Justice for the newly installed Qing Dynasty and supervised the controversial decree forcing the Manchu tonsure onto the Han population as a mark of submission. In 1647, he was sent as an envoy to quell the unrest in Fujian province. After defeating bands of violent warlords funded by the notorious pirate Koxinga, Zhao set up a system of public schools to provide greater economic opportunity for the poor. After the death of his father, Zhao returned to Kaifeng for the three-year mourning period; during that time, he funded the restoration of the synagogue, which had been destroyed in the deluge, and the rectification of the Torah scrolls damaged in that catastrophe. Though the biographical facts are sparse, when these are juxtaposed with the dra- matic events that unfolded during his short lifetime, the potential for a fascinating historical fictionalization emerges. Moreover, many of those historical events in seventeenth-century China--climate change, elite corruption, populist revolt, xenophobia, terrorism, law and order, etc.--resonate with contemporary tropes. The story of ＂The Great Advisor＂ shows how a Jew in seventeenth-century China rose to national prominence at a time when Jews in Europe faced severe discrimination and persecution.展开更多
文摘Chaotic genetic patchiness （CGP） refers to surprising patterns of spatial and temporal genetic structure observed in some marine species at a scale where genetic variation should be efficiently homogenized by gene flow via larval dispersal. Here we review and discuss 4 mechanisms that could generate such unexpected patterns： selection, sweepstakes reproductive success, collective dispersal, and temporal shifts in local population dynamics. First, we review examples where genetic differentiation at specific loci was driven by diversifying selection, which was historically the first process invoked to explain CGP. Second, we turn to neutral demographic processes that may drive genome-wide effects, and whose effects on CGP may be enhanced when they act together. We discuss how sweepstakes reproductive success accelerates genetic drift and can thus generate genetic structure, provided that gene flow is not too strong. Collective dispersal is another mechanism whereby genetic structure can be maintained regardless of dispersal intensity, because it may prevent larval cohorts from becoming entirely mixed. Theoretical analyses of both the sweepstakes and the collective dispersal ideas are presented. Finally, we discuss an idea that has received less attention than the other ones just mentioned, namely temporal shifts in local population dynamics.
文摘Zhao Yingcheng （1619-1657）, known as ＂The Great Advisor＂, is the only Kaifeng Jew who is mentioned both in the synagogal stele of 1663 and in Chinese gazetteers during his lifetime. Zhao, given the Hebrew name of Moshe ben Avram, was fluent in Hebrew but also achieved success as a Confucian scholar familiar with the Chinese classics. He would have witnessed the destruction of his hometown by a catastrophic flood during the 1642 Siege of Kaifeng. In 1645, at the age of 26, he attained the jinshi rank in the Imperial Exams, in which only one in 10,000 can- didates was successful. A year later, he was appointed Minister of Justice for the newly installed Qing Dynasty and supervised the controversial decree forcing the Manchu tonsure onto the Han population as a mark of submission. In 1647, he was sent as an envoy to quell the unrest in Fujian province. After defeating bands of violent warlords funded by the notorious pirate Koxinga, Zhao set up a system of public schools to provide greater economic opportunity for the poor. After the death of his father, Zhao returned to Kaifeng for the three-year mourning period; during that time, he funded the restoration of the synagogue, which had been destroyed in the deluge, and the rectification of the Torah scrolls damaged in that catastrophe. Though the biographical facts are sparse, when these are juxtaposed with the dra- matic events that unfolded during his short lifetime, the potential for a fascinating historical fictionalization emerges. Moreover, many of those historical events in seventeenth-century China--climate change, elite corruption, populist revolt, xenophobia, terrorism, law and order, etc.--resonate with contemporary tropes. The story of ＂The Great Advisor＂ shows how a Jew in seventeenth-century China rose to national prominence at a time when Jews in Europe faced severe discrimination and persecution.
