Production of pure line in fish.

为了通过产生雌核发育二倍体和雄核发育二倍体获得纯系鱼类，研究了泥鳅配子遗传失活和抑制第一次分裂染色体复制的最适条件。用紫外线照射的精子受精30~35min，持续60s，800 kg/cm~2，获得雌核发育二倍体。基因-着丝粒重组率高的基因座上的基因决定了鱼类的完全纯合性。用紫外线照射的卵子与正常精子受精，获得雄核发育二倍体，并在与雌核发育相同的条件下进行压力休克。雌雄配子体鱼类的存活率很低。在许多雌核和雄核发育胚胎中发现了含有一些片段的非整倍体和单倍体。这一事实可能是导致低存活率的一个因素。

In order to obtain pure line of fish by producing gynogenetic and androgenetic diploids, optimum conditions for genetic inactivation of gametes and for chromosome duplication by suppression of the first cleavage were studied in the loach, Misgurnus anguillicaudatus. Chromosome spreads were analyzed to determine ploidy level at embryonic or early fry stages.Gynogenetic diploids were obtained by pressure shocks applied 30-35 min after insemination with UV irradiated spermatozoa and lasting 60 sec, 800kg/cm^2, more than another conditions. Complete homozygosity of the fish was determined by genotypes on the locus with high rate of gene-centromere recombination. Androgenetic diploids were obtained from the eggs irradiated with UV and inseminated with normal spermatozoa, and them pressure-shocked with the same condition as in the case of gynogenesis. Survivals of gyno- and androgenetic fish was very low. Aneuploidy involving some fragments and haploidy were found in many gyno- and androgenetic embryos. This fact may be a factor responsible for low survival.