Toxicology Mechanisms and Methods, 14: 91–95, 2004 Copyright c  Taylor & Francis Inc. ISSN: 1537-6524 print / 1537-6516 online DOI: 10.1080/15376520490257572 Mitochondrial DNA in Polish Centenarians Anna Lorenc Postgraduate School of Molecular Medicine, Warsaw, Poland Katarzyna Tonska and Dagmara Kabzinska Department of Genetics, University of Warsaw, Warsaw, Poland Ewa Bartnik Department of Genetics, University of Warsaw, Warsaw, Poland, and Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland Mitochondrial haplogroups can differ in frequency of occur- rence in those who are 100 years old and in the rest of the popu- lation. These differences are not universally observed; moreover, they are population-specific. We analyzed the haplogroups in 97 Polish 100-year-olds and compared them with those of more than 145 people who served as controls. No statistically significant differ- ences were observed. In additions, we checked D-loop sequences in 31 controls and in some of the centenarians. Statistically significant differences were found for sites 73 and 152 in the D-loop. Keywords Centenarians, D-loop, Haplogroups, Mitochondrial DNA Aging is a phenomenon that has been studied for many years but as yet there are no clear answers to the question What causes human aging? Certainly, there is no one simple explanation, but mitochondria may play a role in the process. This has been postulated for a number of years, as reactive oxygen species are believed to play a role in aging, and mitochondria are a primary site of their generation. Also, some data indicate that longevity may to a large extent be maternally inherited (Sont and Vandenbroucke 1993), as are mitochondria. Cause and effect have not been demonstrated, but two types of investigations have yielded some data concerning the role of mitochondria in aging. The first kind of investigation concerns the accumulation of various types of mitochondrial DNA (mtDNA) mutations in Received 11 June 2003; accepted 19 June 2003. This work was supported by grants PBZ-KBN-022/PO5/1999 and 0529/P05/2001/21 from the State Committee for Scientific Research (KBN), coordinated by the International Institute of Molecular and Cell Biology in Warsaw and by grant ICA-CT-2000 70010 from the Center of Excellence in Molecular Biotechnology. Address correspondence to Ewa Bartnik, Department of Genetics, University of Warsaw and Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02106 Warsaw, Poland. E-mail: ebartnik@ibb.waw.pl the DNA of tissues of aging persons. These data are numer- ous and not always consistent; it is not clear whether the low level of mutations could indeed be responsible for the observed effects. Michikawa and coworkers (1999) and Zhang and col- leagues (2003) demonstrated that certain mutations accumulate in the D-loop of the mtDNA over the course of time. Again, they did not demonstrate that these mutations had any biological effects. The second group of data is based on population studies. There are several hundred mitochondria in practically every hu- man cell, each containing several circular DNA molecules of 16.5 kb each, encoding 22 transfer RNAs (tRNAs), 2 riboso- mal RNAs (rRNAs), and 13 proteins from the electron transport chain (Wallace 1995). There are numerous variants of this se- quence and they have been divided into haplogroups, which are to some extent characteristic of given populations (Macauley et al. 1999; Torroni et al. 1996). The haplogroups can be identi- fied on the basis of restriction analysis or by sequencing of some parts of the mitochondrial genome. Analyses performed in some populations have correlated the presence of certain mitochon- drial haplogroups or of certain mutations within haplogroups with successful aging. Such results have been obtained, among others, for North Italian but not South Italian men (and not for women) and for the Japanese (Tanaka et al. 2000), the French (Ivanova et al. 1998), and the Finnish (Niemi et al. 2003) popu- lations. In each case, various mitochondrial variants are more common among the old than the young. These variants are population-specific, as indeed are mitochondrial haplogroups, therefore data from one population cannot be directly transferred to another. Moreover, these differences have not been found in all populations; for example, in Irish populations, Ross and col- leagues (2001) found no correlation of successful aging with haplogroup J as a whole, although it was found for one of its subgroups. Within the scope of a project analyzing many aspects of suc- cessful aging in Poland, we addressed two questions concerning 91