ISSN 10227954, Russian Journal of Genetics, 2011, Vol. 47, No. 3, pp. 358–363. © Pleiades Publishing, Inc., 2011.
Although lefthandedness makes a small part of
human handedness (between 5–15% people in all cul
tures) , it has always drawn much attention. There
are various biological hypotheses explaining the origin
of handedness as autosomal recessive  or polygenic
determination , an imperfect recessive homozygous
 or heterozygous penetrance . Annett  made
an attempt to formulate a genetic model which
explains both cerebral dominance and handedness.
Thirtyfive years ago handedness was characterized as
an “intriguing phenotype” .
In the right shift theory, Annett  and McManus
 have similar logic that handedness depends on a
single autosomal or singlehandedness gene with two
alleles. The principal difference between the two theo
ries is that Annett treats handedness as a quantitative
trait, and McManus treats it as a binary characteristic.
Laland, Kumm, Van Horm and Feldman 
explained that all humans have a genetic bias to right
handedness, but environmental factor can modify it.
Some cultural transmission of hand preference occurs
between generations, which can account for parent
child similarity of handedness. Individual differences
in handedness on this account are caused by the envi
ronmental factor, not genetic variation .
The article is published in the original.
It still remains unclear why monozygous twins may
differ in handedness.
A popular view is that hand preference itself does
not confer any direct selective advantage. It is a by
product of lateralization of brain function, which was
important for the evolution of language [7, 10]. How
ever, most evolutionary adaptations which are benefi
cial for the species come to predominate in all individ
uals, leading over time to genetic homogeneity.
The binary hand preference data are frequently
interpreted by the multifactorial threshold model,
which describes discrete traits as reflecting an underly
ing normal distribution of liability (or predisposition).
Liability, which represents the sum of all the multifac
torial effects, is assumed to reflect the combined
effects of a large number of genes and environmental
factors, each having small effect, and is characterized
by phenotypic discontinuities that occur when the lia
bility reaches a given threshold .
A number of competing ‘single gene’ models has
been proposed within the literature [7, 8, 12, 13].
While we have not assessed the adequacy of these
models, the polygenic model utilized here appears to
be adequate to our data. Francks et al. [14–16] have
subsequently identified an imprinted gene,
on human chromosome 2, within the 2p12q11
region. Francks explains that this gene affects the sym
metry of the brain, and is not essential for lefthanded
ness, but it can be strong contributing factor.
(Leucinerich repeat transmembrane neuron 1) is
Morphogenetic Variability and Handedness in Montenegro and Serbia
and S. Cvjeticanin
Bureau for Education Services, Section for Biology and Human Genetics, Podgorica 81000, Montenegro
Institute of Human Genetics, School of Medicine, University of Belgrade, Belgrade 11000, Serbia
Received April 26, 2010
—This study tries to establish correlations between the types of handedness and several morpho
physiological characteristics, controlled by one or a small number of genes with alternative dominant reces
sive manifestation. The populationgenetic homozygosity degree study includes the analysis of the presence,
distribution and individual traits combination in lefthanded and righthanded persons. It was conducted at
three localities in two states, Serbia (SRB) and Montenegro (MNE). Our hypothesis is that a possible genetic
load due to increased recessive homozygosity, being a potential populationgenetic parameter of lefthand
edness manifestation, may cause some change in other morphophysiological characters. The average pro
portion of 23 studied homozygouslyrecessive characters (HRC’s) was similar among observed lefthanded
individuals in the studied localities. It varied from
in Serbia to
in MNE. The differences
were somewhat bigger among righthanded persons, varying from
in MNE to
Serbia. However, in all localities the average homozygosity was significantly higher among lefthanded school
children. The number of HRC’s among 400 individuals varied from 2 to 16 among righthanded and from
4 to 19 among lefthanded persons. There were no differences in scholar scores between lefthanded and
righthanded children, although small differences were found between two state samples.