I believe that this is related to my recent post on Y chromosomes and mtDNA of Russians.
How the Slavs conquered Russia (Informnauka (Informscience) Agency):
Geneticist specialists from the Institute of Biological Problems of the North, Far-East Branch of Russian Academy of Sciences, are reconstructing the picture of Eurasia colonization by the Slavs. According to the researchers’ opinion, the Slavonic men and women jointly developed the territory of the south of contemporary Russia. However, after the 9th century, women used to stay at home, and colonization of the east and north was mainly performed by men.
This conclusion was made by geneticists through analyzing variable consecutions of DNA of mitochondria and of some sections of Y-chromosome with representatives of 10 Russian populations from the Stavropol Territory in the south through the Pskov Region in the north and from the Orel Region in the west through the Nizhni Novgorod Region in the east. The mitochondrial DNA is inherited from generation to generation along a female line, DNA of Y- chromosome – along a male line. Analysis of variability of these consecutions allows to judge about migrations of our forefathers and foremothers.
Along the maternal line, Russian populations are rather close to each other. They can be conditionally split into two zones. Inhabitants of the south-eastern zone (including the Orel, Rostov, Kursk, Kaluga and Saratov Regions and the Stavropol Territory) have the roots among western Slavs, Baltic and some Finno-Ugric nations (Poles, Lithuanians and Estonians). Ancestors of Russians in the north-eastern zone took wives from the Finno-Ugric and other nations of Eastern Europe (Finns, Karelians, Maris, Tatars and Adygeis).
Comparison of Y-chromosomes of Russian populations provides different results. Only the Pskov and coast-dweller populations are close along the paternal line to the Finno-Ugric and Baltic nations of the Northern and Eastern Europe, the overwhelming majority of Russians are relatives to the Poles, Ukrainians and Byelorussians. Judging by consecution variations of the “male” chromosome, the Slavs, arriving in various locations of Eastern Europe, contacted in different ways with residential population: in some places - closely and in some others – otherwise.
Genetic analysis results agree with the anthropological data, according to which Russian populations can be divided into three zones. In the western part of the ethnic territory, Russians descend from the Slavs who had come from Central Europe. Russian population of the central part appeared as a result of mixture of the Slavs with the Finno-Ugric nations, Eastern European mothers dominating in these populations, and the population of the North evidently has in its genealogy Finno-Ugric ancestors of both sexes. According to the geneticists, the reasons for these differences are caused by different participation of men and women in Slavonic migrations. Women apparently participated only in early phases of the Slavs’ migration into Eastern Europe. Starting from the 9th century, colonization of the east and the north of Eastern Europe was mainly performed by men who chose wives from residential population. The obtained picture needs more precise definition, therefore the researchers are planning to further investigate variability of specific “maternal” and “ paternal” DNAs in different Russian populations.