Direct segregation analysis of reciprocal translocations: a study of 283 sperm karyotypes from four carriers.
Using the technique of in vitro human-hamster fertilization, sperm of four men heterozygous for 4 reciprocal translocations--t(4;17),t(5;13),t(6;7), and t(9;18)--was studied. Frequencies of numerical abnormalities unrelated to the translocations range from 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 prevalence 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.
Pellestor
F
F
Cytogenetic and Reproductive Biology Laboratory, Grenoble University Medical School, La Tronche, France.
Sèle
B
B
Jalbert
H
H
Jalbert
P
P
D002877:Chromosomes, Human; D006579:Heterozygote; D006801:Humans; D007248:Infertility, Male / Q000235:genetics; D007621:Karyotyping; D008297:Male; D008540:Meiosis; D013094:Spermatozoa / Q000502:physiology*; D014178:Translocation, Genetic