U\I\. IARY \\'e studied the DNA of four clones of three trypanosoma species by CSCl density gladient centrifugatioi\ and electron-inici'OScopy. \\;e found that BIKE\ JouR\AL V01. I+, 203-215,1971 although T. coinisi' AK clone has no kinctoplast it contains satellite DNA \\, ith the same density as 1<1netoplast D\A of T. et:tin$!' 1< clone. To iiTvestigate the 111 sill, localIzation to satellite D\A ill T. eoniisi A1<. clone, \\'e examined thin sections of 'H-thymidine-labelcd pal'asites by

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... ron microscopic radioautographv and studied the DNA released from isolated 1<1netoplast eilvelopcs by, electroi\ microscopy. \\'e found that the extra-nuclear DNA is prcsent in the 1<inctoplast envelope, although extra-nuclear DNA in tivpanosoma \\, itIT kinetoplasts is thouglTt to be concentratcd in the kinetonucleus (an inclusion ii\ the kinetoplast). The ftinction of satellite DNA in T. e"nilsi AK clone is clisctissed in relation to the multiplication of A1< forms. \11nor circular D\A \\. ere fotind both in thc nuclear fraction and tlic 1<inetoplast fraction from T. '11/3i', I'. grill!bitiise and 7'. realisi' K clone. The smallest minoi' DNA had a contour ICngtl\ of 0.11,11. \\'e did 1101 find minor circtilar D\A in preparations from T. errrJisi' A1< clone