REPORT ON A VISIT TO ICELAND AND THE POSSIBLE DEVELOPMENT OF

            HUMAN GENETICS IN ICELAND

13-19 June, 1963

by L,L, Cavalli-Sforza, Director of Genetics Dept.,

University of I&via, Italy,

3


    My interest in Iceland was aroused by the informa-
tion, which I owe to Dr, Liverman, that many Icelanders have
a keen interest in tracing thair ancestry and much genealo-
gical work has been done which may have a genetical interest,
In addition, the well known historical and geographic pecu-
liarities of Iceland make this country a very interesting
place for studies of human genetics,

    I therefore decided to pay a visit to Reykjavik,
which my commitments forced to keep very short, However, I
have been able to make several contacts of importance, The
information to be briefly summarized below was obtained
especially fromseveral discussions with Frof, Niels P. Dun-
gal, who kindly acted as host during my visit, and inter-
views with Dr, Klemenz Tryggvason, chief of the Census Bu-
reau, Dr, Sigurdsson, chief medical officer of Iceland, and
I@, Einar Bjarnason, a specialist in genealogies, I am also
grateful to Mr, S, Spickett who gave me some preliminary
information before my visit,

AVAILABLE DATA

    Current demographic work in Iceland is of a high
standard,, Demographic data are punched on cards, along with
the individual's name0 Cards are used to prepare full popu-
latinn rosters,  ordered by address, Individuals are given
numbers, and the same numbers are used for health insurance
and tax purposes, Demographic records of the conventional ty-
pe are available in printed pubblications from 1910, but in


2,

addition much earlier demographic information is available,
starting in a more or  less regular fashion with the year
17030 It would thus be possible to trace the genealogy of
a large fraction of the population starting from 1700, or
more satisfactorily from 1800,

     Earlier genealogies are also available but are less
trustworthy and cover only a small fraction of the total TO-

pulation,

     Consanguinity data have been made available to me

by Dr, Trygvason, They are being analyzed and it wculd be
worth testing their reliability by a small direct sampling

survey,

     Demographic punched cards have so far been used
with conventional sorting and tabulating machines. A 1401
IBM computer will be available for use by governmental l;u-
reaus in 196Jo

     Medical services are completely socialized and are
of good quality, There is a large number of records availa-

ble in centralized bureaus, The state of health is good and
there are no special sanitary problems, except perhaps that
of gastric carcinoma, which is at present under analysis by
an Icelandic-American team, A large nutritional study is
being carried out with reference to possible nutritional

causes of gastric carcinoma0 There exist blood group data
on some 8000 donors plus some more detailed blood grou-
pings for paternity cases0


30

SOME POSSIBLE DEVELOPKENTS OF RESEARCH IN HUMMN GENETICS

     Probably nowhere else in the world could Vecord
linkage" of the kind started by H,B, Newcombe in Canada
be carried out with smaller cost and better chance of col-
lecting information of genetic, social, medical signifi-

cance,  than in Iceland,

    In fact, it would be a relatively minor effort,
at least in comparison with any other country, to centra-
lize all the information of a genealogic, demographic, eco-
nomic and medical nature already in existence, or easily
available,  so as to have all the information from the various
sources combined together for each individual and made easi-
ly available on magnetic memory,

    A general archive on magnetic disks or tapes could
thus be produced which would contain for each individual, all
data of demographic, medical, social etc, nature, It would
then be easy to trace relatives of any degree for any indi-
vidual, and so obtain all possible correlations between re-
latives for any recorded traits,

    This work could be done in phases, as follows, though
not necessarily in the sequence suggested:

1) addition of information to the present population rosters
necessary to give relationship degrees between living in-

  individuals,, Use of information already contained in the
cards 7 plus some information e.g. from recent marriage
records, would supply only partial indications on close
reiationships between living individuals, To cover the


40

whole population for close relationship (e,g, parent-
offspring, sib-sib) andespecially to obtain more distant
degrees of relationship,  use should be made of informa-

tion from earlier censuses, and other types of records,
including parish books, and, when convenient, published
genealogies of known reliability,,

2) Demographic data,  enriched with information on relation-
ships as in I),  can be linked with socioeconomic and mc-

  dical records from the tax and health insurance offices,

Linkage would b3 L a direct operation in the computer becau-
se of the identification of individuals by numbers.

3) Other sources of data already available, even if referring
only to a fraction of the population, could usefuliy be
added; e,g, information on blood groups (from donors and
paternity tests);  on school curricula; on nutrition etc,

4) Special surveys might be set up with specific aims in

  mind which would benefit enormously from the existence of
all the background information,  especially if this were
made easily available as described above,

    The advantages of carrying out such a program in
Iceland arise from the availability of information not clse-
where available,  from the relatively small size of the coun-
try (180,000 inhabitants), and from the absence of conspi-
cuous immigration, making record linkage comparatively easy
and complete,

     Problems such as population structure, selective and
assortativc mating, genetics of fertility and longevity both
a-t the biological Cand psychological level, would certainly


50

be amenable to satisfactory analysis, It is worth renenbc-
ring how confuse and almost non existent is our knOVlicdgc

on these issues,

     It should also be ncted that the major difficulty
confronting genetic analysis of a great variety of traits,
from physical to behavioural,  is the disentanglement of "so-
cialtt from ttbiologicalt' inheritance, and it is only by ha-
ving all the socioeconomic information that could thus be
made available that the challenge offered by this problem

can be met,

     Becaucz of the rdlctively small population size, the
country does not lend  it self well to research on mutation,
but mutations which have arisen in the past could often be
traced in all the living carriers and this might prove a
good way of measuring fitnesses, If research on selection,
say7 of blood groups wore to be made, it would nof be
inconceivable to typo the whole population, Such data would
certainly be enough for measurin g selection coefficients
down to fairly low values0 No sampling problems and fiw
ascertainment problems would arise on studies conducted on
a population fairly homogeneous socially and economically,
and ~11 cared from the zodical point of view,

     It could be especially fruitful to analyze the
genetics of some special conditions; psoriasis is relative-
ly common in Iceland; alcoholism and gastric carcinoma
should certainly be given much attention also from the ge-
netic point of view, The present interest of research on
gastric carcinoma is centered mostly on nutritional aspects,
but records are collected in such a way that genetic aria-


lysis will be possible. In particular one might mention
tht! hypothesis that the low rate frequency of blood groups
A observed in Iceland might be the cansequence of a high
rate of gastric carcinoma. The higher liability of A indi-
viduals to get gastric carcinoma is known, and it could
be further and more satisfactorily tested in Iceland, along

with its  interaction with environmental conditions,

     In addition to strictly genetical problems, one
should also consider the possibility of collecting in
the archive the history of drugs taken by individuals,
so that retrospective and prospective work on drug to-
xicity could be done,

     Finally,  it should be noted that there exist

some 35,000 Icelanders or Americans of recent Icelandic
origin in the U,S,, which cculd supply a most interesting
control of environmental differences,and/or migration dif-

fzrontials,

     It is difficult, without a special investigation,
to make an esticnte of the cost of such scheme, To suggest
the order of magnitude, a sum of $ 100,OOC a year for fi--

ve years might be considered, It is possible that the Ica-
landic Government would be prepared to share the cost of
such an enterprise,