Kazumichi Katayama

Three-dimensional ontogenetic shape changes in the human cranium during the fetal period

Knowledge of the pattern of human craniofacial development in the fetal period is important for understanding the mechanisms underlying the emergence of variations in human craniofacial morphology. However, the precise character of the prenatal ontogenetic development of the human cranium has yet to be fully established. This study investigates ontogenetic changes in cranial shape in the fetal period, as exhibited in Japanese fetal specimens housed at Kyoto University. A total of 31 human fetal specimens aged from approximately 8 to 42 weeks of gestation underwent helical computed tomographic scanning, and 68 landmarks were digitized on the internal and external surfaces of the extracted crania. Ontogenetic shape change was then analyzed cross‐sectionally and three‐dimensionally using a geometric morphometric technique. The results of the present study are generally consistent with previously reported findings. It was found that during the prenatal ontogenetic process, the growth rate of the length of the cranium is greater than that of the width and height, and the growth rate of the length of the posterior cranial base is smaller than that of the anterior cranial base. Furthermore, it was observed that the change in shape of the human viscerocranium is smaller than that of the neurocranium during the fetal period, and that concurrently the basicranium extends by approximately 8° due to the relative elevation of the basilar and lateral parts of occipital bone. These specific growth‐related changes are the opposite of those reported for the postnatal period. Our findings therefore indicate that the allometric pattern of the human cranium is not a simple continuous transformation, but changes drastically from before to after birth.

Mongoloid populations from the viewpoints of Gm patterns

SummaryGm systems provide unique markers for the study of human genetics, especially for the characterization of a population, the study of gene flow, and genetic drift by the presence of a unique haplotype or by marked differences in the frequencies of identical haplotypes. It has been shown that Gm haplotypes commonly present among Mongoloids are Gmag, Gmaxg, Gmab3st, and Gmafb1b3.The distribution of Gm allotypes has been investigated for the 16 Mongoloid populations from various regions in Asia, North, and South America. A striking aspect of the Gm data from the Mongoloid populations is the presence of a clear geographic cline, especially for the Gmag and Gmafb1b3 haplotypes from Southeast Asia through East Asia into South America. Moreover the Mongoloid populations were divided into two characteristic groups on the basis of the Gm patterns. A geographic cline was also found for the Gmab3st haplotype which is a marker gene of Mongoloids. Discussion was made for the reason why and how such clear geographic cline of the Gm haplotypes has been occurred in the Mongoloid populations.

Genetic study of missing C triradius on the palm: Estimation of the heritability of liability

SummaryPalm prints of 374 parents and 362 children collected from 187 families of Japanese were studied with special reference to a missing c triradius. It was noted that the missing c triradius occurred with significantly increased frequency in the children of affected parents compared with that in all children studied, indicating the presence of genetic factors in its expression. It was suggested that the segregation data were more consistent with the effect of polygenic rather than monogenic inheritance in the causation of this trait. Analysis of the data by Falconers method demonstrated that the heritability of the missing c triradius was calculated to be 105.0±16.3%, indicating the possibility of multifactorial origin with very strong genetic determination (nearly 100%) in the genesis of this trait.

Transferrin variants in Korea and Japan

SummarySeveral transferrin variants detected in surveys of serum samples from Koreans and Japanese have been compared critically with standards and with each other using thin layer agarose gel electrophoresis and polyacrylamide gel electrophoresis.All slow-moving variants were found to have identical mobility with a reference sample of CDChi. Four different fast-moving variants were detected, BKorea 1, BKorea 2, BJap. 1 and BJap. 2. Their relative mobilities at pH 8.9 and 6.5 have been listed and compared with variants described by other investigators.

Genetic study of hypothernar patterns on the palm: Estimation of the heritability of liability

SummaryPalm prints of 349 Japanese families, including 340 pairs of parents and 650 children, were studied with special reference to the inheritance of hypothenar true patterns. It was suggested that the segregation data were more consistent with the hypothesis that hypothenar patternings were transmitted from parents to their children by a multifactorial rather than a simple genetic system. It was demonstrated that individuals with true patterns on both hands had more genetic potential for the patterns than those with unilateral manifestation. The detailed observation of pedigrees revealed that genetic bases corresponding to radial loops and to ulnar loops might be different from each other and that the genes corresponding to radial loops might be related also to the manifestation of carpal loops and whorls. Based on Falconers method, the heritability values were calculated at 63.9±9.0% for the manifestation of radial loops, 75.8±19.8% for that of ulnar loops, and 62.8±10.7% for the bilateral manifestation of radial loops, indicating a considerably strong genetic determination in hypothenar patternings.