KINETOPLAST DNA MINICIRCLES ARE INHERITED FROM BOTH PARENTS IN GENETIC CROSSES OF TRYPANOSOMA-BRUCEI

In the order Kinetoplastida, genetic exchange has been demonstrated on ly in the genus Trypanosoma. Analysis of kinetoplast DNA (kDNA) in gen etic crosses of T. brucei has shown that whereas maxicircles are inher ited uniparentally, minicircles are inherited from both parents. This result was confirmed for a new cross of T. b. brucei and T. b. rhodesi ense by restriction enzyme digestion and Southern analysis of purified kDNA. By hybridisation with small minicircle-derived probes, we could demonstrate the presence of particular parental minicircles in the kD NA of hybrid progeny clones. All hybrid clones had inherited two minic ircles from one parent despite two of the four clones having maxicircl es from the other parent. The results suggest that rather than small-s cale exchange of minicircles between parental networks, gross breakdow n and reassembly of the minicircle network occurs during genetic excha nge.