HERITABILITY AND HETEROMORPHIC DISTRIBUTIONS OF ALUI CHROMOSOME-BANDING VARIANTS IN TWINS

The heritability and heteromorphic appearance of chromosomal banding p atterns induced through in situ digestion with the restriction enzyme AluI were studied by analyzing the chromosomes of 25 monozygotic and 2 5 dizygotic twin pairs selected at random from a juvenile twin registr y. A total of 19 AluI banding variants were found to be heteromorphic, with the pericentromeric region of chromosome 3 and the satellites of chromosome 22 being most and least heteromorphic, respectively. As ex pected, the correlations of the semi-quantitative scores for each of t he chromosomal variants were significantly higher between MZ twin pair s (ranging from 0.48 to 0.95) than DZ twin pairs (ranging from - 0.02 to 0.69), suggesting that genetic factors play an important role in th eir appearance. This finding was confirmed in a model fitting analysis in which the heritabilities of the AluI-induced chromosome variants w ere found to range from 70 to 96% for 12/13 heteromorphisms studied. T hese consistent findings are significant in that these variants may be useful for family studies in clinical genetics. (C) 1995 Wiley-Liss, Inc.