Mitotic metaphase chromosomes of 34 species of Drosophila melanogaster species group were examined. Certain new karyotypes were described for the first time, and their evolutionary and interspecific genetic relationsh...Mitotic metaphase chromosomes of 34 species of Drosophila melanogaster species group were examined. Certain new karyotypes were described for the first time, and their evolutionary and interspecific genetic relationships among 8 subgroups of D. melanogaster species group were analyzed systematically. The results were as follows. The basic karyotype of elegans subgroup was type A. The karyotypes of eugracilis subgroup, melanogaster subgroup, and ficusphila subgroup were all type C. The karyotypes of takahashii subgroup and suzukii subgroup were both type C and type D. The montium subgroup had six kinds of karyotypes types B, C, C＇, D, D＇, and E. The ananassae subgroup had three kinds of karyotypes： types F, G, and H. Thus, the melanogaster species group was classified into five pedigrees based on the diversity of these karyotypes： 1） elegans; 2） eugracilis-melanogasterficusphila; 3） takkahashii-suzukii; 4） montium; 5） ananassae. The above-mentioned results in karyotypic evolution were consistent with those of DNA sequence analysis reported by Yang except for the elegans subgroup and this subgroup was considered as the ancestral subgroup. Karyotype analysis of the same drosophila from different isofemale lines indicated that the same Drosophila from different places showed karyotypic variation which might be due to different geographical environment and evolutionary degree or interaction between the two factors.展开更多
The research history and new discoveries of the specific characteristics of Yulania Spach were reported, as to the specific characteristics, such as the terminal , axillary and fascicled similar flower buds,sometimes ...The research history and new discoveries of the specific characteristics of Yulania Spach were reported, as to the specific characteristics, such as the terminal , axillary and fascicled similar flower buds,sometimes polycymes; 2-4 flower types of a plant; two spathe-like stipoles of single flower; drape or overlap of tepals, deep split or shallow split on the edge of tepals. The discoveries could provide valuable information for the further studies on the taxonomic system, anthotaxical evolution, phylogenetic relationship and breeding.展开更多
目的对2019—2020年辽宁省沿海城市甲型肝炎病毒(hepatitis A virus,HAV)的基因特征进行分析。方法选取2019—2020年辽宁省丹东、大连、盘锦市急性期甲型肝炎患者的血清或粪便标本(共162份),采用巢式PCR法进行HAV VP1/2A序列扩增,阳性...目的对2019—2020年辽宁省沿海城市甲型肝炎病毒(hepatitis A virus,HAV)的基因特征进行分析。方法选取2019—2020年辽宁省丹东、大连、盘锦市急性期甲型肝炎患者的血清或粪便标本(共162份),采用巢式PCR法进行HAV VP1/2A序列扩增,阳性样本进行基因测序,选取28个代表序列,同时从GenBank中下载全球HAV不同型别的基因序列,通过Neighbor-Joining方法构建亲缘关系进化树,分析基因序列同源性。结果2019—2020年辽宁省沿海城市的162份甲型肝炎患者血清及粪便标本中,PCR阳性127份,均为ⅠA型;构建的亲缘关系进化树可分为2个进化分支,即分支1和分支2,与日本、韩国流行HAV的核苷酸同源性分别达98.8%~100%和98.4%~100%。结论2019—2020年辽宁省沿海城市HAV基因型均为ⅠA型,与日本、韩国流行的HAV属同一分支。本研究为辽宁省甲型肝炎的防控提供了实验依据。展开更多
Raptors primarily use soaring-gliding flight which exploits thermals and ridge lifts over land to reduce energetic costs However during migration, these birds often have to cross water surfaces where thermal currents ...Raptors primarily use soaring-gliding flight which exploits thermals and ridge lifts over land to reduce energetic costs However during migration, these birds often have to cross water surfaces where thermal currents are weak; during these times, birds mainly use flapping （powered） flight which increases energy consumption and mortality risk. As a result, some species have evolved strategies to reduce the amount of time spent over water by taking extensive detours over land. In this paper, we con- ducted a meta-analysis of water-crossing tendencies in Afro-Palearctic migrating raptors in relation to their morphology, their flight performance, and their phylogenetic relationships. In particular, we considered the aspect ratio （calculated as the wing span squared divided by wing area）, the energetic cost of powered flight, and the maximum water crossing length regularly performed by adult birds. Our results suggest that energy consumption during powered flight predominately affects the ability of raptors to fly over water surfaces展开更多
基金This work was supported by National Natural Sciences Foundation of China (No. 39930100) International Collaborative Project of Hubei Provincial Department of Education (No. G200610001).
文摘Mitotic metaphase chromosomes of 34 species of Drosophila melanogaster species group were examined. Certain new karyotypes were described for the first time, and their evolutionary and interspecific genetic relationships among 8 subgroups of D. melanogaster species group were analyzed systematically. The results were as follows. The basic karyotype of elegans subgroup was type A. The karyotypes of eugracilis subgroup, melanogaster subgroup, and ficusphila subgroup were all type C. The karyotypes of takahashii subgroup and suzukii subgroup were both type C and type D. The montium subgroup had six kinds of karyotypes types B, C, C＇, D, D＇, and E. The ananassae subgroup had three kinds of karyotypes： types F, G, and H. Thus, the melanogaster species group was classified into five pedigrees based on the diversity of these karyotypes： 1） elegans; 2） eugracilis-melanogasterficusphila; 3） takkahashii-suzukii; 4） montium; 5） ananassae. The above-mentioned results in karyotypic evolution were consistent with those of DNA sequence analysis reported by Yang except for the elegans subgroup and this subgroup was considered as the ancestral subgroup. Karyotype analysis of the same drosophila from different isofemale lines indicated that the same Drosophila from different places showed karyotypic variation which might be due to different geographical environment and evolutionary degree or interaction between the two factors.
基金Supported by Project of Doctor Fund of Henan University of Technology(2006BS015)~~
文摘The research history and new discoveries of the specific characteristics of Yulania Spach were reported, as to the specific characteristics, such as the terminal , axillary and fascicled similar flower buds,sometimes polycymes; 2-4 flower types of a plant; two spathe-like stipoles of single flower; drape or overlap of tepals, deep split or shallow split on the edge of tepals. The discoveries could provide valuable information for the further studies on the taxonomic system, anthotaxical evolution, phylogenetic relationship and breeding.
文摘目的对2019—2020年辽宁省沿海城市甲型肝炎病毒(hepatitis A virus,HAV)的基因特征进行分析。方法选取2019—2020年辽宁省丹东、大连、盘锦市急性期甲型肝炎患者的血清或粪便标本(共162份),采用巢式PCR法进行HAV VP1/2A序列扩增,阳性样本进行基因测序,选取28个代表序列,同时从GenBank中下载全球HAV不同型别的基因序列,通过Neighbor-Joining方法构建亲缘关系进化树,分析基因序列同源性。结果2019—2020年辽宁省沿海城市的162份甲型肝炎患者血清及粪便标本中,PCR阳性127份,均为ⅠA型;构建的亲缘关系进化树可分为2个进化分支,即分支1和分支2,与日本、韩国流行HAV的核苷酸同源性分别达98.8%~100%和98.4%~100%。结论2019—2020年辽宁省沿海城市HAV基因型均为ⅠA型,与日本、韩国流行的HAV属同一分支。本研究为辽宁省甲型肝炎的防控提供了实验依据。
文摘Raptors primarily use soaring-gliding flight which exploits thermals and ridge lifts over land to reduce energetic costs However during migration, these birds often have to cross water surfaces where thermal currents are weak; during these times, birds mainly use flapping （powered） flight which increases energy consumption and mortality risk. As a result, some species have evolved strategies to reduce the amount of time spent over water by taking extensive detours over land. In this paper, we con- ducted a meta-analysis of water-crossing tendencies in Afro-Palearctic migrating raptors in relation to their morphology, their flight performance, and their phylogenetic relationships. In particular, we considered the aspect ratio （calculated as the wing span squared divided by wing area）, the energetic cost of powered flight, and the maximum water crossing length regularly performed by adult birds. Our results suggest that energy consumption during powered flight predominately affects the ability of raptors to fly over water surfaces
