Spontaneous frequencies of aneuploid and diploid sperm in 10 normal Chinese men: assessed by multicolor fluorescence in situ hybridization

Many studies have been published establishing the background frequencies of disomic and diploid sperm in normal men by fluorescence in situ hybridizat ion (FISH) analysis, with highly significant variance among the reports. Be sides interdonor heterogeneity and differences in the experimental protocol s used, the question of inherent differences in chromosome malsegregation a nd meiotic arrest among different geographic and ethnic groups of donors ha s been raised. In this study, multicolor FISH analysis was carried out on s emen samples from 10 nonsmoking, nondrinking Chinese men from the People's Republic of China. The results were compared to FISH data on 10 nonsmoking, nondrinking Canadians under the same experimental conditions, in the same laboratory. A total of 200,497 sperm was scored in the Chinese donors and c ompared to 202,320 sperm from Canadian donors. Approximately 10,000 sperm p er chromosome probe per donor were analyzed. The mean hybridization efficie ncy was 99.99%. The frequencies of X-bearing and Y-bearing sperm were not s ignificantly different from the expected 50% for each individual and for th e combined data from all donors (49.73% vs. 49.46%, P = 0.3946). The mean d isomy frequencies (range) were 0.07% (0.02%-0.12%) for chromosome 13, 0.18% (0.09%-0.19%) for chromosome 21, 0.05% (0.01%-0.09%) for 24,XX, 0.02% (0.0 1%-0.06%) for 24,XX, and 0.29% (0.13%-0.49%) for 24,XY. The mean diploidy f requency (range) was 0.38% (0.22%-0.73%) for 13-21 hybridizations and 0.32% (0.07 %-0.70%) for XY hybridizations. Highly significant interdonor hetero geneity was found for diploidy (P = 0.0000) and for XY disomy (P = 0.0011), but no age effect was observed in any category of disomic or diploid sperm . The data reported here show no marked differences in disomy and diploidy frequencies between the mainland Chinese and Canadian groups, if donor hete rogeneity is taken into account. Copyright (C) 2000 S. Karger AG, Basel.