Bilateral asymmetry in cusp occurrence of the hypoconulid and seventh cusps on the permanent mandibular first molar and the number of cusps on the mandibular premolars was examined in specimens from monozygotic twins, dizygotic twins, and nontwins. Bilateral asymmetry was similar in frequency and displayed no sex or side differences in the three samples.
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References
1.
Van Valen, L.: A Study of Fluctuating Asymmetry, Evolution16:125-142, 1962.
2.
Lundström, A. : Some Asymmetries of the Dental Arches, Jaws and Skull, and Their Etiological Significance, Amer J Orthodont47:81-106, 1961.
3.
Garn, S.M.; LEwis, A.B.; and Kerewsky, R.S.: Bilateral Asymmetry and Concordance in Cusp Number and Crown Morphology of the Mandibular First Molar, J Dent Res45:1820, 1966.
4.
Lundström, A. : Tooth Morphology as a Basis for Distinguishing Monozygotic and Dizygotic Twins, Amer J Hum Genet15: 34-43, 1963.
5.
Race, R.R., and Sanger, R.: Blood Groups in Man, 5th ed, Oxford and Edinburgh: Blackwell Scientific Publications, 1968, pp 1-599.
6.
KRAus, B.S. , and Furr, M.L.: Lower First Premolars: Part I. Definition and Classification of Discrete Morphologic Traits, J Dent Res32:554-564, 1953.
7.
Garrett, H.E.: Statistics in Psychology and Education, 5th ed, New York: David McKay Co., Inc., 1958, pp 235-236.
8.
Siegel, S.: Nonparametric Statistics, New York: McGraw-Hill Book Co., 1956, pp 96-101; 256-270.
9.
Lyon, M.F.: Sex Chromatin and Gene Action in Mammalian X-Chromosomes, Amer J Hum Genet14:135-148, 1962.
10.
Stern, C.: Principles of Human Genetics, 2nd ed, San Francisco: W. H. Freeman and Co. , 1960, pp 1-753.
