用6－甲氨基嘌呤诱导贻贝四倍体胚胎

TETRAPLOID INDUCTION IN THE MUSSEL MYTILUS EDULIS BY APPLICATION OF 6-DIMETHYLAMINOPURINE(6-DMAP)DURING EARLY DEVELOPMENT

在滤过海水中以４×１０（－４）ｍｏｌ·Ｌ（－１）６－甲氨基Ｃ嘌呤（６－ＤＭＡＰ）处理贻贝Ｍｙｔｉｌｕｓｅｄｕｌｉｓ受精卵或胚胎，受精激活后５０或１２０ｍｉｎ处理２０—３０ｍｉｎ，分别抑制第一或第二次有丝分裂，以诱导四倍体胚胎。顶荧光显微观察表明，６－ＤＭＡＰ有效地抑制了第一和第二次卵裂。它使细胞核染色质分散，抑制了原核的移动和染色体的分离，并防碍卵裂沟和极叶的形成，从而诱导出四倍体胚胎。对第一次卵裂的抑制产生８２．８％的四倍体胚胎；第二次卵裂抑制产生５８．６％的四倍体胚胎。由于６－ＤＭＡＰ如此有效，而且价格便宜以及对人体无害，与沿用的化学诱导剂细胞松弛素Ｃ．Ｂ．相比，它应该可以成为双壳类软体动物染色体操作研究的理想化学诱导剂之一。

Eggs or embryos of the mussel M.edulis were subjected to treatment with 4× 10-4mol· L-1 6-DMAP in filtered seawater for 20-30 min applied 50 or 120 min post-activation to inhibit the first or second cleavage respectively, in an attempt to induce tetraploids. The experimental embryo samples were observed and analyzed under epifluo-rescence microscope, using DAPI staining, and the chromatic change was photographed.6-DMAP was observed to cause chromatic de-condensation, block pronuclear migration and chromosome separation, and prevent the formation of the cleavage furrow and the polar lobe. The first or second cleavage was inhibited effectively. Treatment at first cleavage produced an 82. 8% tetraploid rate, and inhibiting second cleavage produced 58. 6%. Considering its effectiveness, inexpensiveness and lack of toxicity, 6-DMAP should be one of the prefered chemical inducer for future chromosome manipulation research in bivalve molluscs.