Inbreeding depression for various traits in two cultured populations of the American bay scallop, Argopecten irradians irradians Lamarck (1819) introduced into China

This paper examines the effect of inbreeding level of population on the magnitude of inbreeding depression expressed by comparing them between two cultured populations (A and B) in the hermaphroditic animal of the bay scallop Argopecten irradians irradians. Population A is expected to have less genetic variations and higher inbreeding level due to longer cultured history (20 generations) and less "ancestral" individuals (26 individuals) than population B due to shorter cultured history (4 generations) and more "ancestral" individuals (406 individuals). Two groups within each population were produced, one using self-fertilization and one using mass-mating within the same population. Selfed offspring (AS and BS) from two populations both had lower fitness components than their mass-mated counterparts (AM and BM) and exhibited inbreeding depression for all examined traits, e.g. lower hatching, less viability and slower growth, indicating that inbreeding depression is a common feature in this animal. Fitness components in all traits of offspring from population A significantly differed those from population B and the magnitude of inbreeding depression for all traits in population A with higher inbreeding level was significantly smaller than that in population B with lower inbreeding level, indicating that both fitness components and magnitude of inbreeding depression were significantly affected by inbreeding level of populations and genetic load harbored in population A may be partially purged through inbreeding. Moreover, the magnitude of inbreeding depression in the two populations both varied among traits and life history stages. The present results support the partial-dominance hypothesis of inbreeding depression. (C) 2008 Elsevier B.V. All rights reserved.

Molecular evidence for the sister relationship of the eastern Asia-North American intercontinental species pair in the Podophyllum group (Berberidaceae)

The presumed pair relationships of intercontinental vicariad species in the Podophyllum group (Sinopodophyllum hexandrum vs. Podophyllum pelatum and Diphylleia grayi vs. D. cymosa) were recently, considered to be paraphyletic. In the present paper, the trnL-F and ITS gene sequences of the representatives were used to examine the sister relationships of these two vicariad species. A heuristic parsimony analysis based on the trnLF data identified Diphylleia as the basal clade of the other three genera, but provided poor resolution of their inter-relationships. High sequence divergence was found in the ITS data. ITS1 region, more variable but parsimonyuninformative. has no phylogenetic value, Sequence divergence of the ITS2 region provided abundant, phylogenetically informative variable characters. Analysis of ITS2 sequences confirmeda sister relationship between the presumable vicariad species, in spite of a low bootstrap support for Sinopodophyllum hexandrum vs. Podophyllum pelatum. The combined ITS2 and trnL-F data enforced a sister relationship between Sinopodophyllum hexandrum and Podophyllum pelatum with an elevated bootstrap support of 100%. Based on molecular phylogeny, the morphological evolution of this group was discussed. The self-pollination might have evolved from cross-fertilization two times in this group. The different pollination and seed dispersal systems of Sinopodophyllum hexandrum and Podophlyllum pelatum resulted from their adaptations to different ecological habitats. The divergence time of Sinopodophyllum hexandrum-Podophyllum pelatum is estimated to be 6.52+/-1.89 myr based on the ITS divergence. The divergence of this species pair predated or co-occurred with the recent uplift of the Himalayas 4-3 myr during the late Miocene and the formation of the alpine habitats. Sinopodophyllum hexandrum developed a host of specialized characters in its subsequent adaptation to the arid alpine surroundings. The present study confirmed the different patterns of species relationship between Asian-North American disjuncts. The isolation of plant elements between North America and eastern Asia must have been a gradual process, resulting in the different phylogenetic patterns and divergence times of the disjuncts.

异文化圈社会规范层次结构模型的比较研究

The relationship between the management and the culture was explored from the view of social norm's theory. In concrete terms, the differences of the hierarchical structure of the social norm among the Chinese, the Japanese and the American were studied systematically by using interview, case study, questionnaire survey and the structure equation model, etc. The results were: (1) The basic two types of the social norms of the Chinese, the American and the Japanese were the same: the external control norm and the internal control norm. The basic dimensions of the two types of norms composed of moral principle, value orientation, the law and the rules, and the social custom were consistent among the three countries. Furthermore, the dimensions of social norms were hierarchical because of the functioning of the different culture, which consisted of the hierarchical structure system. (2) Although there were the same dimensions among the three countries, the contents of these dimensions had both the common norms surpassing the specific culture and the particular norms depending on the specific culture. (3) The basic structures of the social norms in China and in Japan were the same: the internal control norms played a main role and the external control norm was auxiliary. On one hand, within the internal norm of the Chinese, the moral principle was the main force while the value orientation was the supplementary; within the external norm, the law and the rules was the main force while the social culture custom was supplementary. On the other hand, the relationship between the external and the internal dimensions of the Japanese turned out to be contrary to those of the Chinese. (4) The structure of the American social norms were different from the Chinese: for the American, the external control norm played a main role while the internal control norm was assistant. Furthermore, the law and the rule was the major aspect while the social costumes was the second in the external control dimension. In addition, the value orientation led the performance style of the American, while the moral principle played the second role in the internal control structure. (5) The social norms related to the management performance were found including work responsibility, organization commitment, meeting making-decision, communication style, work duty and interpersonal conflict by inventory and case study. The mangers from China, Japan and America had significant different views on paying attention to the management norms. In a word, the culture differences of the social norm were the fundamental reason of the management conflict.