Pellicciari C, Bachmann K
Basic Appl Histochem. 1979;23(2):127-36.
Two North American species of the genus Bufo (Bufo cognatus and Bufo boreas, 2n = 22) and one African species (Bufo regularis, 2n = 20) were analyzed with respect to their repetitive DNA fractions and the behaviour of their chromatin to the acid hydrolysis at different times. The mean melting point of the total isolated DNA decreased from 89 degrees C to 87 degrees C with a genome size increase from 4.4 to 7.5 pg. The differences in genome size can only partly be explained on the basis of repetitive DNA fractions (renaturing up to Cot 10 in 0.12 M phosphate buffer). Several fractions in this repetitive range behave independently in the three species and the spectrum of repetitive fractions in the African Bufo regularis differs distinctly from those of the American toads. When fixed chromatin of these species in histochemical preparations is hydrolyzed with 5N HCl during the Feulgen reaction, the kinetics of depurination are equal in all species, while hydrolytic DNA breakdown proceeds distinctly more slowly in Bufo reularis as compared to the other species.
对北美蟾蜍属的两个物种（北美蟾蜍和北美林蛙，2n = 22）以及一个非洲物种（普通蟾蜍，2n = 20）的重复DNA片段，以及它们的染色质在不同时间对酸水解的反应进行了分析。随着基因组大小从4.4皮克增加到7.5皮克，分离出的总DNA的平均熔点从89℃降至87℃。基因组大小的差异只能部分地根据重复DNA片段（在0.12 M磷酸盐缓冲液中复性至Cot 10）来解释。在这个重复范围内的几个片段在这三个物种中表现独立，非洲普通蟾蜍的重复片段谱与美洲蟾蜍明显不同。当在福尔根反应过程中用5N盐酸水解这些物种组织化学制剂中的固定染色质时，所有物种的脱嘌呤动力学是相同的，而与其他物种相比，普通蟾蜍中水解DNA的降解明显更慢。
