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Presents information on a study which evaluated the effects of human interaction on domestic rabbits. Mitochondrial DNA typing of rabbit breeds; Materials and methods; Results and discussion.

The mitochondrial DNA of the European rabbit (Oryctolugus cuniculus) contains a tandem array of 153-bp repeats in the vicinity of the replication origin of the H-strand. Variation among molecules in the number of these repeats results in inter- and intraindividual length polymorphism (heteroplasmy). Generally, in an individual, one predominant molecular type is observed, the others representing a low percentage of the mtDNA content. At the tissue level, we observe a particular distribution of this polymorphism in the gonads compared with liver, kidneys, or brain, implying a relationship between the differentiation status of the cells and the types of new mtDNA molecules which appear and accumulate during lifetime. Similar tandem repeats were also found in the mtDNA noncoding region of European hares (Lepus europaeus), a cottontail (Sylvilugus~oridunus), and a pika (Ochotonu rufescens). The lengths and the sequences of these units evolve rapidly and in a concerted way, but the number of repeats is maintained in a narrow range, and an internal 20-bp segment is highly conserved. Constraints restrict the evolution of the primary sequence of these repeated units, the number of which is probably controlled by a stabilizing selection. [ABSTRACT FROM AUTHOR]