Successful crossbreeding between Oreochromis niloticus and Sarotherodon melanotheron to produce a commercial hybrid has been difficult.The karyotypes and isoenzyme of these two species and their reciprocal hybrids（O....Successful crossbreeding between Oreochromis niloticus and Sarotherodon melanotheron to produce a commercial hybrid has been difficult.The karyotypes and isoenzyme of these two species and their reciprocal hybrids（O.niloticus ♀ × S.melanotheron ♂,S.melanotheron ♀ × O.niloticus ♂,the last not included in the isoenzyme study） were investigated via metaphase chromosomes obtained from head kidney cells and electropherogram of lactate dehydrogenase（LDH） isoenzymes from the liver,kidney,white muscle,heart,and eye balls.The diploid chromosome number（2n=44） and the fundamental number（NF=50） of the four tilapia genotypes were the same.However,the karyotype of O.niloticus had three pairs of sub-metacentric（sm）,twelve pairs of sub-telocentric（st）,and seven pairs of telocentric（t） chromosomes,while S.melanotheron had one pair of metacentric（m）,two pairs of sm,12 pairs of st,and seven pairs of t chromosomes.The reciprocal hybrids both showed a mixed karyotype range between their parents：0.5 pair of m,2.5 pairs of sm,12 pairs of st,and seven pairs of t chromosomes.In view of the electropherogram of isozymes,only the LDH of the kidney showed significant clear bands,with five bands in O.niloticus,three bands in S.melanotheron,and duplicated six bands in the hybrids.The bands varied depending on their activities and mobilities.We considered that the differences in karyotype and isoenzyme were related to the genetic mechanism for post-mating isolation,and provided some additional basic genetic background of their taxonomy.展开更多
It is introduced that the recent research achievements on honey bee Varroa mites taxonomy and reproductive biology of Dr. Denis L Anderson etc.and our relative research results in China were reported in this paper. Us...It is introduced that the recent research achievements on honey bee Varroa mites taxonomy and reproductive biology of Dr. Denis L Anderson etc.and our relative research results in China were reported in this paper. Using Varroa destructor Anderson & Trueman as the scientific name of the Varroa mites in China instead of the former name? 玍arroa jacobsoni Oudemans.展开更多
Thalassaphorura houtanensis sp. nov. from Shanghai, East China is described. It is similar to T. encarpata （Denis, 1931） in having labial palp of type A and the same pseudocelli formula on the body. It can be distin...Thalassaphorura houtanensis sp. nov. from Shanghai, East China is described. It is similar to T. encarpata （Denis, 1931） in having labial palp of type A and the same pseudocelli formula on the body. It can be distinguished by the shape of unguis, chaetotaxy of labium, maxillary out lobe and ventral tube. It was confirmed as an absolutely parthenogenetic species after a reproduction test in the lab. In addition, the DNA barcoding sequences of this new species were sequenced and analyzed. The intraspecific genetic divergence is 0.18% on average and ranges from zero to 0.46%.展开更多
The worldwide distribution and extensive genetic diversity of the whitefly,Bemisia tabaci,has long been recognized.However,the levels of separation within B.tabaci and the nomenclature of the various genetic groups ha...The worldwide distribution and extensive genetic diversity of the whitefly,Bemisia tabaci,has long been recognized.However,the levels of separation within B.tabaci and the nomenclature of the various genetic groups have been a subject of debate.Recent phylogenetic analyses indicate that B.tabaci is a complex composed of 28 morphologically indistinguishable species.In this article,we first review the debate and difficulties associated with B.tabaci＇s taxonomy and systematics,and argue for the need to apply the biological species concept in order to elucidate B.tabaci＇s systematics.We summarize the accumulated genetic and behavioural data on reproductive incompatibilities evident amongst phylogenetic mtCOI groups of B.tabaci.Crossing studies have been conducted with 14 of the 28 putative species covering 54 reciprocal inter-species pairs,and observations on mating behaviour have been conducted for seven species pairs.Data from both crossing trials and behavioural observations indicate a consistent pattern of reproductive isolation among the putative species.We then discuss the technical and conceptual complexities associated with crossing experiments and behavioural observations designed to reveal reproductive incompatibility.Finally,we elaborate on a strategy for further clarifying the pattern of reproductive isolation between B.tabaci groups and propose future research directions on the systematics of this complex.展开更多
文摘Successful crossbreeding between Oreochromis niloticus and Sarotherodon melanotheron to produce a commercial hybrid has been difficult.The karyotypes and isoenzyme of these two species and their reciprocal hybrids（O.niloticus ♀ × S.melanotheron ♂,S.melanotheron ♀ × O.niloticus ♂,the last not included in the isoenzyme study） were investigated via metaphase chromosomes obtained from head kidney cells and electropherogram of lactate dehydrogenase（LDH） isoenzymes from the liver,kidney,white muscle,heart,and eye balls.The diploid chromosome number（2n=44） and the fundamental number（NF=50） of the four tilapia genotypes were the same.However,the karyotype of O.niloticus had three pairs of sub-metacentric（sm）,twelve pairs of sub-telocentric（st）,and seven pairs of telocentric（t） chromosomes,while S.melanotheron had one pair of metacentric（m）,two pairs of sm,12 pairs of st,and seven pairs of t chromosomes.The reciprocal hybrids both showed a mixed karyotype range between their parents：0.5 pair of m,2.5 pairs of sm,12 pairs of st,and seven pairs of t chromosomes.In view of the electropherogram of isozymes,only the LDH of the kidney showed significant clear bands,with five bands in O.niloticus,three bands in S.melanotheron,and duplicated six bands in the hybrids.The bands varied depending on their activities and mobilities.We considered that the differences in karyotype and isoenzyme were related to the genetic mechanism for post-mating isolation,and provided some additional basic genetic background of their taxonomy.
文摘It is introduced that the recent research achievements on honey bee Varroa mites taxonomy and reproductive biology of Dr. Denis L Anderson etc.and our relative research results in China were reported in this paper. Using Varroa destructor Anderson & Trueman as the scientific name of the Varroa mites in China instead of the former name? 玍arroa jacobsoni Oudemans.
基金supported by the National Natural Science Foundation of China (31301873)
文摘Thalassaphorura houtanensis sp. nov. from Shanghai, East China is described. It is similar to T. encarpata （Denis, 1931） in having labial palp of type A and the same pseudocelli formula on the body. It can be distinguished by the shape of unguis, chaetotaxy of labium, maxillary out lobe and ventral tube. It was confirmed as an absolutely parthenogenetic species after a reproduction test in the lab. In addition, the DNA barcoding sequences of this new species were sequenced and analyzed. The intraspecific genetic divergence is 0.18% on average and ranges from zero to 0.46%.
基金funded by the National Basic Research Program of China(2009CB119203)the National NaturalScience Foundation of China(30730061)the ChinaAgriculture Research System(CARS-25-B-08)
文摘The worldwide distribution and extensive genetic diversity of the whitefly,Bemisia tabaci,has long been recognized.However,the levels of separation within B.tabaci and the nomenclature of the various genetic groups have been a subject of debate.Recent phylogenetic analyses indicate that B.tabaci is a complex composed of 28 morphologically indistinguishable species.In this article,we first review the debate and difficulties associated with B.tabaci＇s taxonomy and systematics,and argue for the need to apply the biological species concept in order to elucidate B.tabaci＇s systematics.We summarize the accumulated genetic and behavioural data on reproductive incompatibilities evident amongst phylogenetic mtCOI groups of B.tabaci.Crossing studies have been conducted with 14 of the 28 putative species covering 54 reciprocal inter-species pairs,and observations on mating behaviour have been conducted for seven species pairs.Data from both crossing trials and behavioural observations indicate a consistent pattern of reproductive isolation among the putative species.We then discuss the technical and conceptual complexities associated with crossing experiments and behavioural observations designed to reveal reproductive incompatibility.Finally,we elaborate on a strategy for further clarifying the pattern of reproductive isolation between B.tabaci groups and propose future research directions on the systematics of this complex.
