Contribution of Genetics and Environment to Craniofacial Anthropometric Phenotypes in Belgian Nuclear Families by ProQuest

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In this study we estimate relative genetic and environmental influences on head-related anthropometric phenotypes. The subject group consisted of 119 nuclear families living in Brussels, Belgium, and included 238 males and 236 females, ages 17 to 72 years. Two factor analyses with varimax rotation (the first one related to facial measurements and the second one to overall head morphology) were used to analyze 14 craniofacial size traits. The resulting four synthetic traits [HFCF, VFCF, HDFl, and HDF2horizontal (breadth) and vertical (height) facial factors and two head horizontal (breadth) factors, respectively] were used as summary variables. Maximum heritabilities (H2) were estimated for all studied traits, and variance components analysis was applied to determine the contribution of genetics and environment on the four craniofacial factors. In addition, we examined the covariations between the face (HFCF and VFCF) and head-related factors (HDFl and HDF2), separately. Quantitative genetic analysis showed that HFCF, VFCF, HDFl, and HDF2 variation was appreciably attributable to additive genetic effects, with heritability (h2) estimates of 67.62%, 54.97%, 70.76%, and 65.05%, respectively. The three variance components reflecting a shared familial environment were nonsignificant for these four phenotypes. Bivariate analysis revealed significant additive and residual correlations for both pair of traits. The results confirm the existence of a significant genetic component determining the four craniofacial synthetic traits, and common genetic and environmental effects shared by the two face-related phenotypes and by the head-related ones. [PUBLICATION ABSTRACT]

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        Contribution of Genetics and Environment to Craniofacial
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        Anthropometric Phenotypes in Belgian Nuclear Families
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5       aline jelenkovic, 1 alaitz poveda, 1 charles susanne, 2 and esther rebato 1
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                Abstract      In this study we estimate relative genetic and environmental in-
8
                fluences on head-related anthropometric phenotypes. The subject group con-
9               sisted of 119 nuclear families living in Brussels, Belgium, and included 238
10              males and 236 females, ages 17 to 72 years. Two factor analyses with vari-
11              max rotation (the first one related to facial measurements and the second
12              one to overall head morphology) were used to analyze 14 craniofacial size                                 [First Page]
13              traits. The resulting four synthetic traits [HFCF, VFCF, HDF1, and HDF2—
14              horizontal (breadth) and vertical (height) facial factors and two head hori-                              [637], (1)
15              zontal (breadth) factors, respectively] were used as summary variables. Max-
16              imum heritabilities (H 2) were estimated for all studied traits, and variance
17              components analysis was applied to determine the contribution of genetics                                 Lines: 0 to 28
18              and environment on the four craniofacial factors. In addition, we examined
                the covariations between the face (HFCF and VFCF) and head-related fac-                                    ———
19                                                                                                                        -2.40256pt PgVar
                tors (HDF1 and HDF2), separately. Quantitative genetic analysis showed that
20              HFCF, VFCF, HDF1, and HDF2 variation was appreciably attributable to                                      ———
21              additive genetic effects, with heritability (h 2) estimates of 67.62%, 54.97%,                            Normal Page
22              70.76%, and 65.05%, respectively. The three variance components reflecting                                 PgEnds: TEX
23              a shared familial environment were nonsignificant for these four phenotypes.
24              Bivariate analysis revealed significant additive and residual correlations for
25              both pair of traits. The results confirm the existence of a significant genetic                             [637], (1)
26              component determining the four craniofacial synthetic traits, and common
27              genetic and environmental effects shared by the two face-related phenotypes
28              and by the head-related ones.
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30      The causes of familial resemblance in and the contribution of genetic and environ-
31      mental factors to craniofacial growth and morphology have been studied in bio-
32      logical anthropology, genetics, anatomy, and dentistry since at least the mid-1940s
33      (Carels et al. 2001; Kohn 1991). Throughout human evolution important anatom-
34      ical modifications have affected skull morphology, particularly, the increase in
35      cranial capacity and the decrease in the facial region. Concerning ontogeny, at
36      birth cranial capacity appears 8 times larger than the facial skeleton, whereas at
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38              1
                  Department of Genetics, Physical Anthropology, and Animal Physiology, Faculty of Science and Technol-
39      ogy, University of the Basque Country, Bilbao 48080, Spain.
                2
                  Laboratory Anthropogenetics, Free University of Brussels, Pleinlaan 2, 1050 Brussels, Belgium.
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41              Human Biology, December 2008, v. 80, no. 6, pp. 637–654.
42              Copyright © 2009 Wayne State University Press, Detroit, Michigan 48201-1309

43           key words: anthropometry, craniofacial size traits, heritability,
44      variance components, belgium.




BOOKCOMP, Inc. — Wayne State University Press / Page 637 / 1st proof / Human Biology 80-6 / December 2008
        638 / jelenkovic et al.

1       the end of the growth period this difference is reduced drastically to 2.5 times.
2       These characteristics make the skull a special part of the skeleton and therefore a
3       subject of considerable interest.
4               The dimensions of the craniofacial complex (including the cranium, face,
5       and cranial base), as for all body-size-related traits, are the result of a complex in-
6       teraction between genetic and environmental factors (e.g., Arya et al. 2002; Baydas
7       et al. 2007; Ermakov et al. 2005; Karmakar et al. 2007). In the literature different
8       heritability estimates have been reported for craniofacial characteristics and dento-
9       facial traits, with values ranging from 20% to 90% (Savoye et al. 1998). To test
10      the hypothesis that head and facial morphology is largely genetically determined,
11      several investigators have studied familial resemblance for craniofacial traits in
12      twins (Savoye et al. 1998; Sharma 1987; Sharma and Susanne 1991; Susanne et al.
13      1983), nuclear families (Johannsdottir et al. 2005; Karmakar et al. 2007; Livshits
14      et al. 1995; Poosha et al. 1984; Sengupta and Karmakar 2007), and more complex                      [638], (2)
15      pedigrees (Ermakov et al. 2005). The familial approach provides evidence of ge-
16      netic and environmental influences not only on variation of individual traits but
17      also in covariation between traits. Such information will help direct molecular,                    Lines: 28 to 38
18      clinical, and epidemiological searches for specific underlying causes (Cui et al.                     ———
19      2002). Other investigators have applied univariate statistical analysis to selected                 0.0pt PgVar
20      anthropometric craniofacial measures (Arya et al. 2002; Byard et al. 1985; Devor                    ———
21      et al. 1
								
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