DIRECT SEGREGATION ANALYSIS OF RECIPROCAL TRANSLOCATIONS - A STUDY OF 283 SPERM KARYOTYPES FROM 4 CARRIERS

  • 1 April 1989
    • journal article
    • research article
    • Vol. 44  (4) , 464-473
Abstract
Using the technique of in vitro human-hamster fertilization, sperm of four men heterozygous for 4 reciprocal translocations.sbd.t(4;17);t(5;13),t(6;7), and t(9;18).sbd.was studied. Frequencies of numerical abnormalities unrelated to the translocations range frmo 8.3% to 13.3%, and the incidence of imbalances ranges from 23.0% to 66.0%. Results are pooled with data from the nine other reciprocal translocations reported elsewhere, and the combined data demonstrate that male meiotic segregation is not random: whatever the type of translocation may be, the distribution of imbalances in sperm is constant, with approximately 72.0% adjacent 1, 18.5% adjacent 2, and 9.5% 3:1 segregations. The same prevalance of adjacent 1 segregations as that reported at term for translocations of paternal origin is observed. There is a strong postzygotic elimination process; for a given translocation it affects selectively the maximum-imbalance zygotes so that imbalanced segregations observed at term are always predetermined.