Y-markers in Finland

Analysis of Y-chromosomal haplogroups has provided much information on the origins and migrations of the Finnish people. The oldest and most common lineages found in Finland belong to the N-haplogroup. A subhaplogroup of N, N1c1 and its branches, show distribution throughout the country, with highest frequencies in eastern Finland (Lappalainen et al. 2006). The occurrence of this haplogroup throughout Eurasia suggests origins in Central Asia about 12,000 years ago with expansion to Northern Europe 2000 years later. The N-haplogroup is associated with the Mesolithic Kunda and Comb Ceramic cultures and also with the non-Slavic ethnic groups of Russia, especially those with a Finno-Ugric or Uralic affinity, such as the Saami, Karelians and Mari (Lahermo et al.

1999; Laitinen et al. 2002; Lappalainen et al. 2006; Rootsi et al. 2007; Lappalainen et al.

2008; Cui et al. 2013;). Today, N-haplogroups show patterns of high occurrence in Northern Eurasia, with low frequencies in Central Europe and Scandinavia (Zerjal et al.

1997; Lahermo et al. 1999; Rosser et al. 2000; Raitio et al. 2001; Laitinen et al. 2002).

Worldwide, the N-haplogroup has its highest occurrence in Finland, specifically Eastern

Finland and Finnish Karelia (70.9%). Though distribution patterns of this haplogroup in

Finland strongly indicate an eastern influence, N1c1 is virtually absent in most Slavic

populations. Indeed, autosomal marker analysis and other evidence have suggested that

Finno-Ugric peoples migrated to Finland long before Slavic ancestors are known to have

inhabited Russia in the 6th and 7th centuries (Lahermo 1999; Salmela et al. 2008). Genetic

and archeological records suggest the earliest post-Pleistocene colonizers of Finland

belonged to Finno-Ugric groups, with this small group of migrants arriving from the east, settling first the northwestern frontier of ice-free Eurasia and later expanding towards central and eastern areas of the country (Sajantila et al. 1996; Lahermo et al. 1999;

Lappalainen et al. 2006; Palo et al. 2009). In surrounding areas to the west, N1c1 is relatively rare, with a frequency of 9.5% in Sweden as a whole (Karlsson et al. 2006).

The Y-haplogroups found in Finland include N1c1, I1, R1a1, R1b and E1b1, in

descending order of frequency. The two largest family categories N and I have several

sub-branches together encompassing much of central Europe and Eurasia, but within

Figure 8. Y-chromosomal haplogroups found in Finland, and their migration paths. The Y-haplogroups found in Finland include N1c1, I1, R1a1, R1b and E1b1, in descending order of frequency.

Finland they have been further narrowed down into subclades N1c1 and I1a. Through the two millennia following the emergence of the N-parent haplogroup M-231, its geographic movement occurred in a counterclockwise pattern through Asia, from southern China towards Siberia. The frequency of subclade N1c1-Tat (M-46) occurs in a gradient from Siberia to Europe, with greatest occurrence in Finland and the Central Siberian plateau with varying frequencies between. It is thought that this subclade experienced a period of expansion in Siberia and at length a migration towards northern Europe some 10,000 years ago. The I-haplogroup M-170 is thought to have arisen some 22,000 years ago in the Balkan area of Europe, after the last glacial maximum and well before the spread of the Neolithic culture into Europe from the Fertile Crescent 10,000 years ago. From the Balkans, carriers of Hg I migrated further into Europe, and arrived in the Nordic area via western Europe (Rootsi et al. 2004).

The most common haplogroups in modern Europe (R1a, R1b and I) are in the minority in Finland (Lappalainen et al. 2006). The subhaplogroup I1-M253 and its further branches are most prominent in the Scandinavian countries and western Finland, with greatest frequency of I1-M253 in central Sweden (52%) (Karlsson et al. 2006; Lappalainen et al.

2009). In Finland I1 shows highest concentration in the western provinces (40%) and lowest in Eastern Finland (19%) (Lappalainen et al. 2006). The subhaplogroups observed in Finland are younger than those occurring in mainland Sweden, suggesting that migration occurred from the direction of Scandinavia to the coasts of western Finland.

Thus current understanding of Nordic population history suggests that the I-haplogroup arrived to Finland from Scandinavia sometime after the colonization and dispersal of the N-haplogroup (Rootsi et al. 2004). This later immigration seems to have been limited mostly to the southwestern parts of the country.

Although no DNA associated with the N-haplogroup has been recovered from ancient human remains, archeological evidence combined with genetic chronologies have indicated that this haplogroup is likely affiliated with Mesolithic cultures (Shi et al. 2013;

Cui et al. 2013). Although data on prehistoric I-haplogroup samples is also very limited, samples from individuals belonging to haplogroup I2 have been recovered from Neolithic burial sites in Europe (Haak et al. 2010; Lacan et al. 2011a; Lacan et al. 2011b; Lee et al.

2012). These ancient DNA findings provide further support to the notion that the Neolithic

culture was spread at least in part by groups carrying the I-haplogroup, but only after

association with the original Neolithic migration from the Near East into the Balkans, the

birthplace of this haplogroup. The frequency of HgI in the Near East is low, and it has

been suggested that members of the I clades (eg. I2a1b-M423) adopted agriculture from

migrants from the Anatolian area (Battaglia et al. 2009). NGS analysis of ancient samples

recovered from Europe has indicated recent (3.5 - 7.5 kya) coalescent times for I1-M253,

R1a-M198 and R1b-M269 (Batini et al. 2015). The arrival of the Corded Ware culture

signaled the dawn of the agricultural lifestyle in Finland, and archeological finds from this

era show the presence of domesticated animal bones in Åland (Storå 2000). The

coalescence age of I1-M253 also supports a Neolithic arrival for this haplogroup into

Finland (Lappalainen et al. 2008). The two cultures eventually gave rise to the Kiukainen culture, a hybrid between earlier Comb Ceramic and the immigrant Corded Ware cultures.

It is from this period that the first confirmed evidence of animal husbandry and cereal

cultivation in Finland has been discovered (Bläuer & Kantanen 2013).

In document Finnish population genetics in a forensic context (sivua 44-47)