The genetic composition of the main race groups in Finland
Carl O. Nordling
However, the solid blood group investigation
of Nevanlinna (1973) made it dear that the Finns are
genetically different from the Estonians, and that the Finland-Swedes differ from
the Swedes in
In order to determine the proportions of
genes from various sources in the current gene pool of a certain population, one
or more mathematical methods are needed.
The first method that presents itself for
the purpose is the concept of the so-called genetic distance. This distance is
measured as a kind of average of a number of gene-frequency differences between
the two populations in question. (For simplicity's sake, I have used the square
root of the mean of all the separate gene differences squared.)
If a certain people, A, has genetic distances
to two other peoples, B and C, which distances add up to the distance between
B and C (or a little more), it would indicate the possibility of A being a mixed
breed composed of genes from B and C. In the case of the Icelanders, for instance,
their distances to the Norwegians and to the Irish add up to about twice the distance
between the latter two. Consequently, the genetic distances do not mark the Icelanders
as a mixed breed composed of Norwegians and Irishmen. Obviously, measuring genetic
distances is not enough to solve the problem of determining the components of
a mixed breed; but it may be a useful first step. At a stage when such components
have been determined, distances may also be used to determine the proportions
of the components.
Nevanlinna (1973)
has provided excellent statistics with frequency figures for 19 allele genes,
distributed according to counties and language groups, covering all of
One of my working hypotheses was that the
counties that shared a common dialect would also share some genetic traits which
would distinguish them from other dialect groups. It appeared that this was indeed
the case. For example - as will be shown below -, the Finns in the counties where
the Häme dialect is spoken (i.e. the counties of Häme,
Figure
1 shows the genetic distances between four of the race groups concerned (Finland-Swedes,
Häme-Finns, East-Finns and a sample group of Estonians)
graphically. It appears that the Häme-Finns are not
far from being a perfect match to a mixed breed between Finland-Swedes and East-Finns.
However, there are reasons to suspect that the latter two groups are both of mixed
breeding themselves; they may even have been compounded later than the Häme-Finns.
Since the East-Finns obviously have less
of the Swedish component than the Häme-Finns and the
Finland-Swedes, one would expect them to be very close to their linguistic relatives,
the Estonians. But astonishingly enough, the genetic distance between the Estonians
and the East-Finns is the longest of all.
Measuring genetic distances per se
does not tell us how these race groups have been mixed together. That being the
case, why not try the option introduced by Mark (1970), the "Europidity index "? According to the allele statistics
of Ryman et al. (1981) the Swedes share with other Europeans a high frequency
of - for instance - the allele genes N and P, which at the same time show lower
frequencies among all the five groups under scrutiny here. If the frequency values
of these two genes among the Swedes are given index values of 100 and the frequency
values among the Estonians are given index values of, say, 45, we obtain the following
provisory index values of "Europidity" for
all our groups:
As
a working hypothesis, we may assume that the Estonian gene pool is composed of
just two components, the "Europidity" component
and another, let us call it the "Estonidity"
component. The alleles B and Cde have especially high
values among the Estonians and lower ones among all the other groups. These two
genes may therefore be taken as markers of "Estonidity".
Using the same procedure as above, we arrive at the following provisory index
values of "Estonidity":
Since
- to take one example - the East-Finns only rate 42 and 27 on the Europidity and Estonidity scales,
respectively, there is reason to expect a third, unknown component in their gene
pool. This unknown component must be characterized by rather extreme frequencies
of certain alleles, especially A2, Fya, Gc1 and cde.
The East-Finns rate higher than any other of the relevant groups in respect of
the first three of these and rather low where cde is
concerned.
Let us make the temporary assumption
that the gene pool of the East-Finns contains just 42% pure Swedish genes and
27% "Proto-Estonian" genes (i.e. such as would combine with the former
to form the gene pool of present-day Estonians). The remaining 31% of the gene
pool of the East-Finns would then constitute the unknown component, the "X".
Applying the above assumptions, we may calculate the rates for "X" on
the ''marker alleles, A2, Fya, Gc1 and cde.
As
far as the tables of Mourant et al. (1976) go, there
is only one people in the world that meets this description.
It is the Saamis.All subgroups of Saamis
have A2 values between .14 and .37 - a peculiarity that distinguishes the Saamis from all other peoples. As for Fya
and Gc1, groups of Saamis have frequencies up to .82
and .97, respectively. The Saamis are also noted for
very low frequencies of the allele group cde (.06 -.29).
Clearly, than, "X " represents
a Saami group - probably one found among the North-Eastern
Saamis tat now populate parts of northern
It
must be noted immediately that the calibration of the three index scales presented
above is not derived from any calculation. We have simply assumed that the Estonians
rate 45 on Europidity and the East-Finns 31 on NE-Lappidity
as a temporary device, if it can be proved that three genetic components will
suffice to describe the composition of the gene pools of the groups under scrutiny,
there still remains the problem of measuring the real proportions of these components.
I have tried to solve the problem by means
of constructing three hypothetical gene sets that may be blended together in various
proportions to form acceptable copies of the gene sets of the East-Finns, the
Häme-Finns, the South-West-Finns and the Finland-Swedes.
At the same time, I have required that one of the hypothetical sets be typically
Scandinavian, another typically NE-Lapponian and the third such that it will produce the established
Estonian gene set when blended in the proportion 55 to 45 with the first set (the
"Scandinavian" one).
The attempt succeeded in part. Three hypothetical
basic sets that meet the said requirements will indeed suffice to make good copies
of the established gene sets of the East-Finns, the Häme-Finns and the Finland-Swedes. At the same time, though,
it became quite clear that no mix of any three components fulfilling the requirements
could possibly match the gene set of the South-West-Finns. The most likely explanation
of this state of things is that the gene pool of the South-West-Finns contains
not only the three components described above but also a fourth, unknown component.
Identifying this component is of course a challenge.
In order to make the three components appropriate
for finding the required gene sets of today, it was necessary to assume that the
Scandinavian component should diverge rather markedly from the average frequencies
among all groups of Swedes.
(Certain
subgroups usually do diverge considerably from the average of the group as a whole.)
By carefully studying the regional frequency tables of Beckman (1959), a possible
explanation of this discrepancy was discovered; it turned out that the deviation
from the frequencies among Swedes in general may be accounted for by means of
assuming that the well-suited Scandinavian component is, in its turn, composed
of one part genes from Swedish Saamis (SW-Saamis)
and five parts genes from Swedes of the sub-group that now populates southern
Norrland and northern Dalecarlia.
In other words, the peculiarities of the Scandinavian component can be satisfactorily
explained if we regard it as compounded in the manner described.
The frequencies of 19 allele genes in all
were used to test the hypothesis that the race groups in
Given
these four basic gene sets as ingredients at our disposal, we may now calculate
the best recipe for blending proportions when it comes to making a copy of each
of the gene sets of the East-Finns, the Häme-Finns and
the Finland-Swedes. This calls for a procedure of successive trials and adjustments.
So far, I have found the best recipes to be the following ones: See also Figure
2).
The
numerical values should not be regarded as a true-to-life description of the genetic
composition of the groups in question, because the proportions could easily be
raised or lowered a little by slightly changing the frequency values of the components.
The important thing is that no such tamping would change the general pattern of
genetic composition that has been deduced here. It is also important to point
out that there exists no alternative theory that would describe the genetic composition
of these race groups in some other way.
References
Beckman,
L.
Mark, K. 1970. Zur Herkunft der Finnisch-ugrischen Völker vom Standpunkt der Anthropologie, Taflinn.
Mourant, A.E., Kopec, A.C. & Domaniewska-Sobczak, K. 1976. The distribution of the human blood
groups,
Nevanlinna, H.R. 1973. Soumen väestörakenne. Kansaneläkelaitoksen julk. A. 9. Helsinki.
Ryman,
N. et al. 1981. Probability of paternity exclusion
in different mother-child genotype combinations. Hereditas
94.