McCombie Helen, Ledu Christophe, Phelipot Pascal, Lapègue Sylvie, Boudry Pierre, Gérard André
Institut Français pour la Recherche et Exploitation de la Mer, Laboratoire d' Génétique et Pathologie, La Tremblade, 17390, France,
Mar Biotechnol (NY). 2005 Jul-Aug;7(4):318-30. doi: 10.1007/s10126-004-0440-2. Epub 2005 May 5.
We present a new method to produce tetraploid Crassostrea gigas by cytochalasin B inhibition of polar body 2 expulsion in diploid females crossed with tetraploid males. This offers a means of direct introgression of genetic characters from selected diploid to tetraploid lines, avoiding a triploid step. Offspring larval ploidy shifted over time and depended on size, with tetraploids more frequent among the smaller larvae and triploids among the large. Viable tetraploids were found at 4 and 6 months, indicating the technique was successful. The possibility that gynogenesis occurred was tested by microsatellite analysis to confirm the presence of paternally inherited alleles. These were present in all animals of the 2n x 4n + CB (female first) cross. However, a 4n x 2n + CB cross produced triploids, including some gynogens. Our method illustrates for the first time that diploid C. gigas eggs, if selected for large size, can give viable tetraploid offspring.
我们提出了一种新方法，通过用细胞松弛素B抑制与四倍体雄性杂交的二倍体雌性排出第二极体来产生四倍体太平洋牡蛎。这提供了一种将选定二倍体的遗传特征直接渗入四倍体系的方法，避免了三倍体步骤。后代幼虫的倍性随时间变化，并取决于大小，较小的幼虫中四倍体更为常见，而较大的幼虫中三倍体更为常见。在4个月和6个月时发现了可存活的四倍体，表明该技术是成功的。通过微卫星分析测试了雌核发育发生的可能性，以确认父本遗传等位基因的存在。这些等位基因存在于2n×4n + CB（雌性先处理）杂交的所有动物中。然而，4n×2n + CB杂交产生了三倍体，包括一些雌核发育个体。我们的方法首次表明，如果选择大尺寸的二倍体太平洋牡蛎卵，就可以产生可存活的四倍体后代。
