Family Tree DNA: Genetic Testing Service
Many Balkan people have already taken advantage of DNA testing to learn about their connections with other families and ethnic groups, both near and far. Once you've submitted your DNA sample, you'll be eligible to join the "Romania" project if you have ancestors who lived in Romania in either or both of the genetic lines being tested. They don't limit their membership to ethnic Romanians.
Romania is a Balkan country in the lower Danube valley. It's located north of Bulgaria, southwest of Ukraine and Moldova, southeast of Hungary, and east of Serbia. Transylvania is a famous region of the country.
The much smaller Moldova is also a Romanian-speaking country and there is considerable debate about whether Moldovans are really a separate people from Romanians. I personally consider them to be the same people.
The Romanian language sounds beautiful and belongs to the Romance family in the Eastern Romance division. Once written in a form of the Cyrillic alphabet even in the 16th-19th centuries in much of Romania proper, but in Latin in Transylvania, during most of the 20th century the split was Latin in Romania proper and Cyrillic in Soviet-controlled Moldova. In 1989 Moldova switched to the Latin script, so today Romania and Moldova both use the same writing system.
In comparison with other European ethnic groups, it is comparatively hard
(as of 2012) to find detailed data on Romanian DNA.
Nevertheless, I was able to find the following estimates for the frequencies
of Y-DNA haplogroups among Romanian people:
22.2% I or I2
Haplogroup I is also common in Bosnia and Herzegovina, in Serbia, in Croatia, in Sardinia, and in Scandinavian countries. Some of these peoples, especially Sardinians and Serbs, are believed to primarily descend from among the earliest European settlers, prior to successive waves of new immigrations from the Near East.
Haplogroup I2a1b is found in especially high frequencies in northeastern Romania, Moldova, and central Ukraine.
I tried to parse out ethnic Romanians in Family Tree DNA's "Romania" group. As far as I can tell, for non-Jewish non-Hungarian non-German non-Roma ethnic Romanians their Y-DNA haplogroups include E1b1b1, G, I1, I2a, Q, and R1b1a2. This is in line with the expectations from the frequencies above. Their mtDNA haplogroups include H, H7, I, J, K1c1, M, U4, and U5.
Siiri Rootsi, Chiara Magri, Toomas Kivisild, Giorgia Benuzzi, Hela Help, Marina Bermisheva, Ildus A. Kutuev, Lororka Barać, Marijana Pericić, Oleg Balanovsky, Andrey Pshenichnov, Daniel Dion, Monica Grobei, Lev A. Zhivotovsky, Vincenza Battaglia, Alessandro Achilli, Nadia Al-Zahery, Jüri Parik, Roy King, Cengiz Cinnioğlu, Elsa Khusnutdinova, Pavao Rudan, Elena Balanovska, Wolfgang Scheffrahn, Maya Simonescu, Antonio Brehm, Rita Goncalves, Alexandra Rosa, Jean-Paul Moisan, Andre Chaventre, Vladimir Ferak, Sandor Füredi, Peter J. Oefner, Peidong Shen, Lars Beckman, Ilia Mikerezi, Rifet Terzić, Dragan Primorac, Anne Cambon-Thomsen, Astrida Krumina, Antonio Torroni, Peter A. Underhill, A. Silvana Santachiara-Benerecetti, Richard Villems, and Ornella Semino. "Phylogeography of Y-chromosome haplogroup I reveals distinct domains of prehistoric gene flow in Europe." American Journal of Human Genetics 75:1 (July 1, 2004): pages 128-137. First electronically published on May 25, 2004. This study found that 22% of the people of Romania and Moldova belong to the Y-DNA haplogroup I.
Alexandru Varzari, W. Stephan, V. Stepanov, F. Raicu, R. Cojocaru, Y. Roschin, C. Glavce, V. Dergachev, M. Spiridonova, H. D. Schmidt, and E. Weiss. "Population history of the Dniester-Carpathians: evidence from Alu markers." Journal of Human Genetics 52:4 (2007): pages 308-316. First published electronically on February 16, 2007. Based on Alexandru Varzari's dissertation "Population History of the Dniester-Carpathians: Evidence from Alu Insertion and Y-Chromosome Polymorphisms" for the Faculty of Biology Ludwig-Maximilians-Universität on July 27, 2006. Abstract:
"The area between the Dniester and the eastern Carpathian mountain range is at a geographical crossroads between eastern Europe and the Balkans. Little is known about the genetics of the population of this region. We performed an analysis of 12 binary autosomal markers in samples from six Dniester-Carpathian populations: two Moldavian, one Romanian, one Ukrainian and two Gagauz populations. The results were compared with gene frequency data from culturally and linguistically related populations from Southeast Europe and Central Asia. Small genetic differences were found among southeastern European populations (in particular those of the Dniester-Carpathian region). The observed homogeneity suggests either a very recent common ancestry of all southeastern European populations or strong gene flow between them. Despite this low level of differentiation, tree reconstruction and principle component analyses allowed a distinction between Balkan-Carpathian (Macedonians, Romanians, Moldavians, Ukrainians and Gagauzes) and eastern Mediterranean (Turks, Greeks and Albanians) population groups. The genetic affinities among Dniester-Carpathian and southeastern European populations do not reflect their linguistic relationships. The results indicate that the ethnic and genetic differentiations occurred in these regions to a considerable extent independently of each other. In particular, Gagauzes, a Turkic-speaking population, show closer affinities to their geographical neighbors than to other Turkic populations."
Maria A. Perkova, Urszula Rogalla, Tomasz Grzybowski, Elza K. Khusnutdinova, Irina Dambueva, and Ilia Zakharov. "Complete Mitochondrial DNA Analysis of Eastern Eurasian Haplogroups Rarely Found in Populations of Northern Asia and Eastern Europe." PLoS ONE 7(2) (February 21, 2012): e32179. Excerpts:
"[...] The results of our study provided an additional support for the existence of limited maternal gene flow between eastern Asia/southern Siberia and eastern Europe revealed by analysis of modern and ancient mtDNAs previously [...] It is noteworthy that another eastern Asian specific lineage, C5c1, revealed exclusively in some European populations (Poles, Belorussians, Romanians), shows evolutionary ages within frames of 6.6-11.8 kya depending on the mutation rates values . [...] Prehistoric migrations associated with the distribution of the pottery-making tradition initially emerged in the forest-steppe belt of northern Eurasia starting at about 16 kya and spread to the west to reach the south-eastern confines of eastern European Plain by about 8 kya  could be suggested as a potential cause for eastern Asian mtDNA haplogroups appearance in Europe. [...]"
Footnote 12 in the above article by Perkova et al. cites the article below:
Miroslava V. Derenko, Boris Abramovich Malyarchuk, Tomasz Grzybowski, Galina A. Denisova, Urszula Rogalla, Maria A. Perkova, Irina Dambueva, and Ilia Zakharov. "Origin and post-glacial dispersal of mitochondrial DNA haplogroups C and D in northern Asia." PLoS One 5: e15214. Excerpt:
"Several mtDNAs with the same control-region motif were detected earlier at a low frequency in some European, Asian and southern Siberian populations - in Poles (0.4%), Belorussians (0.3%), Romanians (0.6%), Persians (0.2%), Kirghiz (1.1%), Altaians (0.9%), Teleuts (7.5%), Khakassians (0.9%) and Shors (4%) , , -."Footnote 26: B. Egyed, A. Brandstätter, J. A. Irwin, Z. Pádár, T. J. Parsons, and W. Parson, "Mitochondrial control region sequence variations in the Hungarian population: analysis of population samples from Hungary and from Transylvania (Romania)," in Forensic Sci. Int. Genet. 1 (2007): pages 158-162.
Simon C. Heath, Ivo G. Gut, Paul Brennan, James D. McKay, Vladimir Bencko, Eleonora Fabianova, Lenka Foretova, Michel Georges, Vladimir Janout, Michael Kabesch, Hans E. Krokan, Maiken B. Elvestad, Jolanta Lissowska, Dana Mates, Peter Rudnai, Frank Skorpen, Stefan Schreiber, José M. Soria, Ann-Christine Syvänen, Pierre Meneton, Serge Herçberg, Pilar Galan, Neonilia Szeszenia-Dabrowska, David Zaridze, Emmanuel Génin, Lon R. Cardon, and Mark Lathrop. "Investigation of the fine structure of European populations with applications to disease association studies." European Journal of Human Genetics 16 (2008): pages 1413-1429. Romanian data is included. Excerpt:
"A striking feature of the samples used for this study is how well the geographic origin of the samples appears to correlate with the genetic origin, so that separating the samples by country of origin or on the basis of genetic measures gives similar results. The only major deviation from this pattern is with the Romanian samples that appear to be closer to the Spanish samples (further 'west') than their geographic position would indicate. This could be because of the historical close ties between Romania and Italy, but further studies would be required to confirm this."
G. Cardos, V. Stoian, N. Miritoiu, A. Comsa, A. Kroll, S. Voss, and Alexander Rodewald. "Paleo-mtDNA analysis and population genetic aspects of old Thracian populations from South-East of Romania." Romanian Society of Legal Medicine 12:4 (2004): pages 239-246. To what degree, if any, are the ancient Thracian people related to modern-day Romanians? That was a goal of this study. Excerpts:
"We have performed a study of mtDNA polymorphisms (HVR I and HVR II sequences) on the skeletal remains of some old Thracian populations from SE of Romania, dating from the Bronze and Iron Age in order to show their contribution to the foundation of the modern Romanian genetic pool and the degree of their genetic kinships with other old and modern human European populations. [...] Computing the frequency of common point mutations of the present-day European population with the Thracian population has resulted that the Italian (7.9%), the Albanian (6.3%) and the Greek (5.8%) have shown a bias of closer genetic kinship with the Thracian individuals than the Romanian and Bulgarian individuals (only 4.2%). [...] So far we can just suppose, that the old Thracian populations would have been able to contribute to the foundation of the Romanian modern genetic pool. More mtDNA sequences from Thracian individuals are needed in order to perform an complex objective statistical analysis."
Alexander Rodewald, G. Cardos, and C. Tesio. "Analysis of mitochondrial DNA haplotypes of old human populations from the Bronze and Iron Age from Romania." A paper to be presented at The European Human Genetics Conference 2012 in Nuremberg, Germany, June 23-26, 2012. Thracian Turks descend from local people who converted to Islam when the Ottoman Empire controlled the region. Excerpts from the Abstract: "Our genetic study was focused on old human populations from the Bronze and Iron Ages from Romania [...] Concerning the genetic relationships at mitochondrial level, old human populations from Romania have shown closer genetic relationship to Turks of Thracian origin, while modern Romanians were closer to modern Bulgarian, Italian, Greek and Spanish populations."