关于鲂鱼(平胸鳊)种类的新资料

<正> 鳊鱼类是我国鲤科鱼类中分布得很广的一类经济鱼。从1846年理查逊(Rich-ardson)首先记述起,许多中外鱼类学者就陆续地发表了这方面的材料。到目前为止,鱼类分类学者多数认为中国的鳊鱼类应分别属于两个属,即鳊属——Pa-rabramis,和鲂属——Megalobrama。鳊属中仅有一个种,即是鳊鱼——Parabramis

Molecular cytogenetic detection of paternal chromosome fragments in allogynogenetic gibel carp, Carassius auratus gibelio Bloch

In gynogenesis, sperm from related species activates egg and embryonic development, but normally does not contribute genetically to the offspring. In gibel carp, Carassius auratus gibelio Bloch, however, gynogenetic offspring often show some phenotypes apparently derived from the heterologous sperm donor. This paternal effect of allogynogenesis is outstanding in an artificial clone F produced by cold treatment of clone E eggs after insemination with blunt-nose black bream (Megaloabrama amblycephala Yin) sperm. Karyotype analysis revealed 5-15 supernumerary microchromosomes in different individuals of clone F in addition to 156 normal chromosomes inherited from the maternal clone E. A painting probe was prepared from the microdissected microchromosomes, and used to investigate the origin of these microchromosomes. Strong positive signals were detected on each microchromosomes of clone F and on 4 pairs of chromosomes in blunt-nose black bream, whereas no signals were detected on the chromosomes of clone E. This result indicates that some paternal chromosome fragments of blunt-nose black bream have been incorporated into the artificial clone F. Therefore, the manipulation of allogynogenesis may provide a unique method to transfer DNA between diverse species for fish breeding.