TY - JOUR
T1 - AluI-resistant chromatin of chromosome 18
T2 - classification, frequencies and implications
AU - Babu, Arvind
AU - Verma, Ram S.
AU - Patil, Shivanand R.
PY - 1987/6
Y1 - 1987/6
N2 - The pericentric chromatin of chromosome 18 was found to be far more heterogeneous for restriction endonuclease AluI (5′ ··· AG ↓ CT···3′) than previously thought. The extent of such heterogeneity was characterized using 50 normal Caucasians and 5 cases of trisomy 18 or Edwards' Syndrome. The AluI-resistant chromatin can arbitrarily be classified into at least five sizes by comparison with the length of the short arm (p) of chromosome 18. They are: negative (1), small (2), medium (3), large (4) and very large (5) with incidences of 11.30%, 19.13%, 29.57%, 29.57% and 10.43%, respectively. In addition the location of the chromatin can be classified into four types depending upon the position relative to the primary constriction. For example: Type I (absent); Type II (present on p arm only); Type III (present on q arm only); Type IV (present on centromere and extending into both p and q arms). The incidences of types I, II, III, and IV were 11.30%, 62.61%, 0.87%, and 25.22%, respectively. Based on limited data, AluI-resistant chromatin was found to be predominantly "large" and "very large" in Edwards' Syndrome samples. In addition, no case with negative Alu-resistant chromatin was noted. Therefore, it is tempting to speculate that the amount of chromatin present on the centromere might play a role in non-disjunction in Edwards' Syndrome cases. Although the variation observed in the present study is continuous, the proposed classification has some important implications for future investigations.
AB - The pericentric chromatin of chromosome 18 was found to be far more heterogeneous for restriction endonuclease AluI (5′ ··· AG ↓ CT···3′) than previously thought. The extent of such heterogeneity was characterized using 50 normal Caucasians and 5 cases of trisomy 18 or Edwards' Syndrome. The AluI-resistant chromatin can arbitrarily be classified into at least five sizes by comparison with the length of the short arm (p) of chromosome 18. They are: negative (1), small (2), medium (3), large (4) and very large (5) with incidences of 11.30%, 19.13%, 29.57%, 29.57% and 10.43%, respectively. In addition the location of the chromatin can be classified into four types depending upon the position relative to the primary constriction. For example: Type I (absent); Type II (present on p arm only); Type III (present on q arm only); Type IV (present on centromere and extending into both p and q arms). The incidences of types I, II, III, and IV were 11.30%, 62.61%, 0.87%, and 25.22%, respectively. Based on limited data, AluI-resistant chromatin was found to be predominantly "large" and "very large" in Edwards' Syndrome samples. In addition, no case with negative Alu-resistant chromatin was noted. Therefore, it is tempting to speculate that the amount of chromatin present on the centromere might play a role in non-disjunction in Edwards' Syndrome cases. Although the variation observed in the present study is continuous, the proposed classification has some important implications for future investigations.
UR - http://www.scopus.com/inward/record.url?scp=0023248292&partnerID=8YFLogxK
U2 - 10.1007/BF00330345
DO - 10.1007/BF00330345
M3 - Article
C2 - 3038486
AN - SCOPUS:0023248292
SN - 0009-5915
VL - 95
SP - 163
EP - 166
JO - Chromosoma
JF - Chromosoma
IS - 3
ER -